WO2008120215A2

WO2008120215A2 - Intra-articular implant for treating irregularities in cartilage surfaces

Info

Publication number: WO2008120215A2
Application number: PCT/IL2008/000456
Authority: WO
Inventors: Hamid Sharim; Shmuel Beck
Original assignee: Novocart Medical Solutions Ltd
Priority date: 2007-04-02
Filing date: 2008-04-02
Publication date: 2008-10-09
Also published as: WO2008120215A3

Abstract

An implant for use in the treatment of damaged cartilage within a joint, the implant is adapted to be inserted into a cavity of the joint and reduce stress on the cartilage engendered, for example, by patient activity. The implant may form an internal cushion, which protects the cartilage such that wearing forces. The cushioning effect facilitates regeneration of the cartilage.

Description

INTRA-ARTICULAR IMPLANT FOR TREATING IRREGULARITIES IN CARTILAGE SURFACES

FIELD OF THE INVENTION

The invention relates to methods and apparatus for promoting regeneration of cartilage.

BACKGROUND OF THE INVENTION

Cartilage, due to its physiological characteristics has minimal ability to repair itself. The forces that are exerted on the cartilage inhibit healing even further. Thus, even small damages in the cartilage, if remain untreated, can hinder a subject's ability to move without pain, and cause deterioration to the joint surface.

Four levels of cartilage damage, particularly in Chondromalacia Patellae (which is a degenerative condition of the cartilage surface of the back of the knee cap, or patella), are generally defined. The first level includes a superficial damage to the cartilage and generally does not require any treatment. The second level includes a deeper damage to the cartilage, which is often accompanied with pain. The third and fourth levels include massive degradation of the cartilage and in severe cases even a partial or complete exposure of the bone. Patients suffering from these levels of damage experience significant pain and mobility reduction.

Among the common causes for cartilage damage are the following:

Injuries (such as fracture(s), damage to the cartilage itself, the tendon(s), ligament(s) and/or meniscus), reoccurring injuries, for example in athletes;

Post trauma conditions that lead to further cartilage damage after the injury; and

- Joint disease, such as osteoarthritis (OA), which is also known as degenerative arthritis or degenerative joint disease. OA is a condition, often occurring in elderly people, in which low-grade inflammation results in degradation (wearing) of the cartilage that covers and acts as a cushion inside joints, such as knees, hips, elbows and other joints). The degradation of the cartilage leads to pain in the joints. Inflammation of the surrounding joint capsule (complete envelopes surrounding the joint) often due to breakdown products from the cartilage which are released into the joint space. New bone outgrowths, called "spurs" or osteophytes, can form on the margins of the joints, possibly in an attempt to improve the congruence of the articular cartilage surfaces. These bone changes, together with the inflammation, can be both painful and debilitating. OA patients experience pain particularly upon weight bearing, including walking and standing. Due to decreased movement because of the pain, regional muscles may atrophy, and ligaments may become more lax.

Existing treatments to cartilage damage include:

Systemic application of medicines, such as NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) and physiotherapy. This treatment is often applied in mild cases of a second level of cartilage damage.

Local injections of steroid agents such as glucocorticoid and/or hyaluronic agent, for example, synvisc or hyaluronan. This treatment, which may be used in any level of cartilage damage, allows only temporary pain relief and some suppression of the friction within the joint.

Arthroscopy, which is a surgical procedure in which a small fiberoptic telescope (arthroscope) is inserted into a joint, while the surgeon can view the procedure on a monitor. During arthroscopy the surgeon can, for example, remove or repair of a torn meniscus or cartilage, reconstruct ligament(s), remove loose debris, and trim damaged cartilage. Other treatment that may be performed during arthroscopy includes shaping the damaged part of the cartilage and allowing a new connective tissue (such as a scar tissue) to grow and replace the missing part of the cartilage. Arthroscopic treatments are generally performed in severe cases of a second level of cartilage damage and also in third or fourth levels of cartilage damage.

Arthroscopy is less traumatic to the joint tissues, such as the cartilage, muscles and ligaments, than the traditional method of open surgery of the joint. The benefits of arthroscopy involve smaller incisions, faster healing, a more rapid recovery, and less scarring. However, the results obtained by the existing arthroscopic methods are partial and often only temporary, particularly in more progressed stages of cartilage damage (levels 3-4), in which the success rates are very low (typically as low as 3-4%). More information about arthroscopy may be found at http://www.arthritis.org/conditions/surgerycenter/surgerycenterflash/arthroscopy.html, which is herein incorporated by reference, in its entirety.

Severe cases of joint conditions (such as level 4 of cartilage damage), may be treated with irreversible and invasive procedures such as joint replacement surgery. This procedure, which includes an opening of the joint, has a limited success chance and in a case of failure must be performed over and over again until satisfying results are obtained. In addition, joint replacement surgery requires a lengthy recovery time of the patient and may induce multiple complications such as infections. More information about level 4 cartilage damage may be found at http://orthoinfo.aaos.org/fact/thr_report.cfm?Thread_ID=442&topcategory=Knee, which is herein incorporated by reference, in its entirety.

Alternative and less common treatments to cartilage damage include, for example, treatment with Autologous Chondrocyte Implantation (ACI). ACI includes harvesting chondrocyte (cartilage generating cells) from a patient's joint, typically a knee, and culturing and multiplying them. The fresh chondrocytes are then reimplanted in the patient's joint and cause hyaline cartilage to regenerate. This procedure may be performed using arthroscopic methods. More information about arthroscopy may be found at http://www.scoi.com/carticel.htm, which is herein incorporated by reference, in its entirety. The success rates of ACI are not yet known.

There is thus a need in the art for new and improved apparatus and methods for efficiently treating joint conditions with minimal invasiveness and healing time.

The term "cartilage" refers to a type of dense connective tissue composed of collagenous fibers and/or elastic fibers, and cells called chondrocytes, all of which are embedded in a firm gel-like ground substance called the matrix. Cartilage is avascular (contains no blood vessels) and nutrients are diffused through the matrix. The term "cartilage" refers to any kind of cartilage, for example, articular (hyaline) cartilage (which is most prominently found in diarthroidal joints covering long bones, such as the femur and the tibia which connect at the knee) fibrocartilage (which is most permanently present in the intervertebral disks of the spine, as a covering of the mandibular condyle in the temporomandibular joint, and in the meniscus of the knee), and elastic cartilage (which naturally exists in the epiglottis and the eustachian tube). More information about the structure and function of cartilage may be found at http://www.chelationtherapyonline.com/articles/pl79.htm, which is incorporated herein by reference in its entirety.

The term "diarthroidal joint(s)" (or synovial joints or diarthroses) refers to the most common and most moveable type of joints in the body. As with all other joints in the body, synovial joints achieve movement at the point of contact of the articulating bones. Structural and functional differences distinguish the synovial joints from the two other types of joints in the body, with the main structural difference being the existence of a cavity (a joint cavity, such as a knee cavity) between the articulating bones and the occupation of a fluid in that cavity which aids movement. More information about diarthroidal joints may be found at http://en.wikipedia.org/wiki/SynovialJoint, which is incorporated herein by reference in its entirety.

The term "joint(s)" refers to the location at which two or more bones are functionally connected. Joints are constructed to allow movement and provide mechanical support, and may be classified structurally and functionally. More information about joints may be found at http://en.wikipedia.org/wiki/Joint, which is incorporated herein by reference in its entirety.

There are no satisfactory alternatives to surgery for tendon repair today; however, research is providing encouraging findings. Although there is no presently approved drug that targets this notoriously slow and often incomplete healing process, a cellular substance recently discovered at the Lawrence Berkeley National Laboratory may lead to a new drug that would improve the speed and durability of healing for injuries to tendons and ligaments. The substance, called Cell Density Signal-1, or CDS-I, by its discoverer, cell biologist Richard Schwarz, acts as part of a chemical switch that turns on procollagen production. Procollagen is a protein manufactured in large amounts by embryonic tendon cells. It is transformed outside the cell into collagen, the basic component of such connective tissues as tendons, ligaments or bones. Amgen Inc. is planning to use genetic engineering to bring CDS-I into mass production.

Prolotherapy represents a less invasive alternative to surgery. It is a form of treatment that stimulates the repair of injured or damaged structures. It involves the injection of dextrose or natural glycerin at the exact site of an injury to stimulate the immune system to repair the area. Thus, prolotherapy causes an inflammatory reaction at the exact site of injuries to such structures as ligaments, tendons, menisci, muscles, growth plates, joint capsules, and cartilage to stimulate these structures to heal. Specifically, prolotherapy causes fibroblasts to multiply rapidly. Fibroblasts are the cells that actually make up ligaments and tendons. The rapid production of new fibroblasts means that strong, fresh collagen tissue is formed, which is what is needed to repair injuries to ligaments or tendons.

It is therefore another long felt and unmet need to provide a device and method for more efficacious tendon repair

SUMMARY OF THE INVENTION

An aspect of some embodiments of the invention relates to providing methods and apparatus for promoting regeneration of cartilage.

According to an aspect of some embodiment of the invention, cartilage regeneration is promoted by reducing stress on the cartilage, optionally, while enabling a patient to engage in substantially normal activity.

According to an aspect of some embodiment of the invention, cartilage degradation is inhibited by reducing stress on the cartilage, optionally, while enabling a patient to engage in substantially normal activity.

An aspect of some embodiments of the invention relates to providing an implant for use in the treatment of damaged cartilage within a joint. The implant is adapted to be inserted into a cavity of the joint and reduce stress on the cartilage engendered, for example, by patient activity. The implant may form an internal cushion, which protects the cartilage such that wearing forces (such as pressure, friction, squeezing, stretching, bending, sliding, twisting, pulling and other forces) on the cartilage are reduced. The cushioning (padding) effect facilitates regeneration of the cartilage.

According to an aspect of some embodiments the invention, there is provided a method of promoting cartilage regeneration, the method includes inserting an implant which includes a padding material in a joint of interest. The method may further include shaping and/or inflating the implant, for example by inserting fluid to the implant. Shaping and/or inflating the implant may be applied, for example, in order to induce a desired cushioning effect. The method may further include deflating the implant, for example, by extracting the fluid from the implant.

According to an aspect of some embodiments the invention, the cartilage is articular cartilage, such as knee cartilage.

According to an aspect of some embodiments of the invention, the implant is adapted to impose a shaping force upon the cartilage. According to an aspect of some embodiments of the invention, the implant has a surface that contacts the damaged cartilage and is adapted to facilitate cartilage regeneration. In some embodiments of the invention, at least a portion of the implant's contact surface promotes the formation of a substantially smooth cartilage surface. In other embodiments of the invention, at least a portion of the implant's contact surface promotes the formation of a substantially rough cartilage surface.

According to an aspect of some embodiments of the invention, the implant, for example, the implant's surface, may include a medicament adapted to promote cartilage healing and/or to inhibit cartilage degradation. Such medicaments may include for example, NSAIDs (Nonsteroidal Anti-Inflammatory Drugs), steroid agents such as glucocorticoid and/or hyaluronic agent, for example, synvisc or hyaluronan. The medicament may be adapted for immediate release or sustained release, for example, embedded within a matrix, such as a polymeric matrix.

In an embodiment of the invention, the implant may be a temporary implant. The temporary implant may be removed from the joint after a certain period of time, for example upon achieving a certain result, such as sufficient tissue reconstruction. In another embodiment of the invention, the implant may at least partially undergo degradation or dissolve in the body. In an embodiment of the invention, the implant may include a balloon adapted to be inserted into a joint and to be inflated with fluid after insertion. The inflated balloon is adapted to assume a shape that occupies at least a portion of the joint cavity and thus protects the cartilage and impede the damaged cartilage reconstruction. After a certain period of time or upon achieving a desired medical result, the fluid may be extracted and optionally, the balloon may be removed from the joint.

In an embodiment of the invention, the implant may include a gel-like material, such as silicone gel, optionally encapsulated within another material, such as a silicone shell. The (optionally encapsulated) gel-like material is adapted to be inserted into a joint, for example by a needle, and to occupy at least a portion of the joint cavity. The (optionally encapsulated) gel-like material may form a padding layer, optionally having a flat shape (or rough). This padding layer protects the cartilage from wearing forces that may impede the damaged cartilage reconstruction.

Optionally, the implant may be anchored to the joint in order to minimize undesired migration within the joint. Anchoring may be performed, for example, by sewing a portion of the implant to a soft tissue in proximity to or within the joint.

According to another aspect of the invention the aforementioned the surgical implant is adapted to repair an intraarticular fracture.

According to some aspects of the invention the aforementioned articular fracture is selected from a group consisting of knee fracture, ankle fracture, elbow fracture, shoulder fracture, foot fracture, wrist fracture or hand fracture.

According to another aspect of the invention devices and methods are disclosed for repairing damaged tendons

According to another aspect of the invention devices and methods are adapted for repairing damaged nerves

The terms "cartilage regeneration" or "cartilage reconstruction" refer to any process that includes the formation of a new cartilage tissue and/or any other tissue, for example, connective tissue and/or a scar tissue, substantially in or proximate to a location normally occupied by cartilage. BRIEF DESCRIPTION OF FIGURES

Examples illustrative of embodiments of the invention are described below with reference to figures attached hereto. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below.

Figs. IA and IB schematically show a knee in extension (A) and in flexion (B), in accordance with an embodiment of the invention;

Fig. 2 schematically shows a partial view of a longitudinal cross section of a knee in extension, in accordance with an embodiment of the invention;

Fig. 3A schematically shows a partial view of a longitudinal cross section of a knee in extension, receiving an implant, in accordance with an embodiment of the invention;

Fig. 3B schematically shows a partial view of a longitudinal cross section of a knee in extension, receiving an implant, in accordance with an embodiment of the invention;

Fig. 3C schematically shows a partial view of a longitudinal cross section of a knee in extension, receiving an implant, in accordance with an embodiment of the invention; and

Fig. 4 schematically shows optional implants, in accordance with an embodiment of the invention.

Fig. 5 schematically shows an embodiment of the invention.

Fig 5a schematically shows another embodiment of the invention

Fig. 6 schematically shows an embodiment of the invention

Fig. 7 schematically shows a detail of an embodiment of the invention

Fig. 7a schematically shows a detail of an embodiment of the invention

Fig 8 schematically shows an embodiment of the invention

Fig 9 schematically shows an embodiment of the invention DETAILED DESCRIPTION OF EMBODIMENTS

Figs. IA and IB schematically show a knee 100 in extension (Fig. IA) and a knee 102 in flexion (Fig. IB), in accordance with an embodiment of the invention. The knee 100 is essentially made up of four bones: the femur 104, the tibia 106, the fibula 108 and the patella 110. The femur 104, which is the large bone in the thigh, attaches by ligaments and a capsule to the tibia 106. Just below and next to the tibia is the fibula 108, which runs parallel to the tibia 106. The patella 110, also called the kneecap, rides on the knee joint as the knee bends (Fig. IB). The articular cartilage 112 and the meniscus 114 are cartilaginous elements within the knee joint serve to protect the ends of the bones from rubbing on each other and to effectively deepen the tibia 106 sockets into which the femur 104 attaches. The ACL (anterior cruciate ligament) 116 is connected to the tibia 106 on one end and to the femur 104 on the other end and prevents the tibia 106 from being pushed too far anterior relative to the femur 104. The LCL (lateral collateral ligament) 118 is connected to the fibula 108 on one end and to the femur 104 on the other end and protects the lateral side from an inside bending force. The patellar tendon (ligament) 120 is connected to the pattela 110 on one end and to the tibia 106. The patellar tendon (ligament) 120 helps give the patella 110 its mechanical leverage.

Fig. 2 schematically shows a partial view of a longitudinal cross section of a knee 200 in extension, in accordance with an embodiment of the invention. Three bones are shown in the knee 200: the femur 202, the tibia 204 and the fibula 206. Also shown are the articular cartilage 212 of the femur 202, the articular cartilage 208 of the tibia 204 and the knee capsule 210. The articular cartilage 212 has a damaged section 214 and the articular cartilage 208 has a damaged section 216. The damaged section 214 of the articular cartilage 212 and the damaged section 216 of the articular cartilage 208 are shown to be located in the medial compartment part of the knee 200, but may occur in any other section of the articular cartilage 208 and/or 216, independently. The damaged section 214 of the articular cartilage 212 and the damaged section 216 of the articular cartilage 208 may be a result of any number of factors such as those described herein, for example, injuries (such as fracture(s), damage to the cartilage itself, the tendon(s), ligament(s) and/or meniscus), reoccurring injuries, post trauma conditions and joint diseases, such as osteoarthritis (OA). A knee cavity 218 is schematically shown between the femur 202 and the tibia 204. Figs. 3A-3C schematically show different stages of a knee 300 in extension (partial view of a longitudinal cross section), receiving an implant 316, in accordance with an embodiment of the invention. Three bones are shown in the knee 300: the femur 302, the tibia 304 and the fibula 306. Also shown are the articular cartilage 312 of the femur 302, the articular cartilage 308 of the tibia 304 and the knee capsule 310. The articular cartilage 312 has a damaged section 314 and the articular cartilage 308 has a damaged section 316. As described herein, the damaged section 314 of the articular cartilage 312 and the damaged section 316 of the articular cartilage 308 are shown to be located in the medial compartment part of the knee 300, but may occur in any other section of the articular cartilage 308 and/or 316, independently. The damaged section 314 of the articular cartilage 212 and the damaged section 216 of the articular cartilage 208 may be a result of any number of factors such as those described herein. A knee cavity 318 is schematically shown between the femur 302 and the tibia 304. An implant 319 is being inserted into the knee cavity 318 in proximity to damaged section 314 and damaged section 316. In Fig. 3A the implant 319 is shown in deflated state, in other words, containing substantially no fluid or containing only a partial amount of fluid. The implant 319 may be a balloon, which may be comprised of silicone or any other appropriate material or combination of materials such as polyurethane and it's derivatives, silicone rubber and it's derivatives or a modified biological material such as a proteoglycan reduced soft tissue xenograph. The implant 319 includes an inflation tube 324 adapted for filling the implant 319 with fluid (not shown). The fluid may include a low viscosity fluid, such as water, saline, hyaluronic acid, air carbon Dioxide or any other appropriate fluid. The implant 319 and the inflation tube 324, as shown in Fig. 3A, are inserted into the knee cavity 318 using an insertion tube 322. The insertion tube 322 may be for example, a needle a catheter, an injector, such as manual or automatic injector or any other appropriate means capable of inserting an implant, such as implant 319. As shown in Fig. 3B, the implant 319 is being positioned in the knee cavity 318 and the insertion tube 322 is being gradually or rapidly removed. The implant 319 is being inflated with fluid. The inflation with fluid can be performed during the removal of the insertion tube 322. The inflation with fluid can also be performed (or continued) after at least a part of the insertion tube 322 has been removed. The procedure of inserting an implant as disclosed herein, such as implant 319, may be a part of an arthroscopic procedure that can be performed under local or general anesthesia. The insertion tube 322 may thus be a part of arthroscopic equipment. After the implant 319 has been inflated to the desired extent, the inflation tube may include a sealed port adapted for inserting and/or extracting fluid to or from the implant 319. For example, in a case that after the insertion of the implant (such as implant 319), if it is found necessary to fill more fluid into the implant, it is possible to fill the fluid through a port or tap (which may be a part of the inflation tube 324 but may also be another part functionally associated with the implant, such as implant 319). The port can also be used for extraction of fluid from the implant 319, for example prior to the extraction of the implant 319 from the knee. Fluid can also be inserted and/or extracted from the implant 319 in order to reshape the implant 319 and thus apply the desired shaping force on the damaged cartilage, such as damaged section 314 and damaged section 316. The port may be comprised of a flexible material, such as rubber or silicone, which can be re-sealed after the insertion of a needle for inserting and/or extracting fluid. The inflation tube 324, which may or may not include a port, can also be used for anchoring the implant 319 to the joint in order to minimize undesired migration within the joint and to allow accessible insertion and/or extraction of fluid. Anchoring may be performed, for example, by sewing a portion of the implant to a soft tissue in proximity to or within the joint and/or the joint capsule 310. Of course, any implant as disclosed herein, such as implant 319, may include more than one inflation tubes 324 and/or one or more anchoring elements for anchoring the implant, such as implant 319, to more than on location such as the knee capsule 310.

The implant as refered to herein may also comprise a gel-like material and/or semi-fluid material (in addition to or instead of a balloon), such as silicone gel, optionally encapsulated within another material, such as a silicone shell. The (optionally encapsulated) gel-like implant can be inserted into a joint such as the knee 300, as described in Figs. 3A-3C, for example by an insertion tube (such as the insertion tube 322 as described in Figs. 3A-3C) and to occupy at least a portion of the joint cavity (such as the knee cavity 318 as described in Figs. 3A-3C). The (optionally encapsulated) gel-like implant may form an optionally flat, padding layer, which protects the cartilage from wearing forces that may impede the damaged cartilage reconstruction. The gel-like implant, for example silicone gel implant, which may optionally be encapsulated within another material, such as a silicone shell may have one or more anchoring elements adapted to anchor the implant in the joint, such as a knee and prevent its migration. The anchoring elements may be similar in structure to the inflating tube 324 of implant 319 described herein. In addition, the implant, such as implant 319 or any other appropriate implant, for example, the implants as disclosed herein, may be a permanent or temporary implant which is used as a padding material adapted to pad the cartilage such that wearing forces are reduced on the cartilage. Reduction of at least a portion of the wearing forces normally being exerted on the cartilage in the joint, such as on damaged sections 314 and 316, allows the cartilage to heal, repair and/or regenerate. The implant, which includes a padding material, is adapted to protect the cartilage during the process of healing, repairing and/or regenerating.

In addition, the implant, such as implant 319 or any other appropriate implant may, for example, the implants as disclosed herein, may be adapted to impose a shaping force upon the cartilage. The implant may further be adapted to impose a substantially smooth surface on the cartilage reconstructing. Since the implant, which includes a padding material, is designed to "wrap" the cartilage, when the cartilage heals, repairs and/or regenerates, the newly formed tissue (such a connective tissue) may assume the shape, such as a smooth shape, of the implant.

After a period of time, such as 1-12 weeks or more particularly 6-8 weeks, the implant can be removed from the joint. The temporary implant may also be removed from the joined after a certain result (such as sufficient tissue reconstruction and/or pain relief) was obtained or whenever the physician finds it appropriate.

The figures disclosed herein describe a knee only as an example of a joint into which the implant may be inserted. However, it is noted that the implants according to the invention may be used in any other joint for example, hip, elbow, finger joints and others.

The figures disclosed herein describe damaged cartilage sections in the medial section of the joint, which is a common situation, for example in OA (osteoarthritis). However, it is noted that the damaged cartilage sections may be in any other part of the joint, for example, in the lateral part of the joint. The implant may be positioned in the appropriate place according to the damaged section.

Reference is now made to Fig. 4, which schematically shows optional implants, in accordance with an embodiment of the invention. Figs. 4A, 4B and 4C show different shapes of deflated implants (balloon type implants or gel- like implants) 400, 402 and 404 respectively, in accordance with an embodiment of the invention.

Figs. 4A\ 4B' and 4C show implants 400, 402 and 404 in the inflated form, the deflated implants are marked 400', 402' and 404' respectively, in accordance with an embodiment of the invention.. The deflated implants 400', 402' and 404' are packed within insertion tubes 401, 403 and 405 respectively.

Figs. 4A and 4A' show implants 400 and 400' having no anchoring elements and/or inflation tubes.

Figs. 4B and 4B' show implants 402 and 402', having one anchoring element and/or inflation tube 404 and 404' respectively.

Figs. 4C and AC show implants 406 and 406', each having two anchoring elements and/or inflation tubes 408, 410 and 408', 410', respectively.

Reference is now made to figs 5 and 5a which schematically shows optional embodiments of an implant with anchoring tabs for securing the implant to soft tissue in or near the joint space. The hatched are represents the inner portion adapted to accommodate an infill, and the unhatched outer area represents the outer envelope portion. It is herein acknowledged that the relative sizes of the outer portion and the inner portion vary according to the specific requirements of any specific embodiment. It is further acknowledged that the inner portion may be infilled or not according to specific requirements of a particular embodiment of the invention. It is further herein acknowledged that the inner portion may be solid, semi solid or hollow according to the specific requirements of a particular embodiment of the invention. Of course, other shapes or forms of implants are also possible and are not limited by any of the drawings.

The invention has been described using various detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. The described embodiments may comprise different features, not all of which are required in all embodiments of the invention. Some embodiments of the invention utilize only some of the features or possible combinations of the features. Variations of embodiments of the invention that are described and embodiments of the invention comprising different combinations of features noted in the described embodiments will occur to persons with skill in the art. It is intended that the scope of the invention be limited only by the claims and that the claims be interpreted to include all such variations and combinations.

The inner concept of the invention is an inflatable implant for temporary implantation into a patient knee which provides both shock absorbance and reshaping of the diseased or injured joint. A removable implant adapted for short term residence in the knee, which can be filled with slow release therapeutic agents is further disclosed herein. Without wishing to be bound by theory, embodiments of the invention are further disclosed wherein the regeneration of type II cartilage in a damaged synovial joint is stimulated. The aforementioned regeneration may be promoted by the release of narcotics, medicaments, hormones and local anti inflammatory drugs. The anti inflammatory drugs may be NSAID's or corticosteroids. The aforementioned regeneration may also be promoted by the massaging and smoothing effect of the aformentinoed surgical implant as the bones of the joint move, possibly stimulating relocation and reseeding of healthy chondrocytes on areas of the synovial capsule which have been excessively worn. Regeneration may also be envisaged as being stimulated by controlled abrasion provided by controlled release of abrasive materials selected from a group consisting of diamond dust, aluminium oxide powders, salts, minerals, all said same diluted or suspended in mineral oil or solvents. The materials are released into the synovial joint from the implant at predetermined rates, quantities and intervals. In some embodiments of the invention the implant will have a somewhat raised texture, in the form for example of treads, bumps, indentations, nipples and the like, in order to provide reshaping effects on the synovial surfaces .

Reference is now made to fig 5 which is a schematic representation of an embodiment of a temporary surgical implant for a damaged synovial joint, especially the knee joint, useful for insertion into the synovial space of said joint. The implant provides separation between bones of the joint, softened mechanical contact and reshaping of the joint and regeneration of cartilage. The implant comprises an infilled member wherein the member comprises

a. an outer envelope portion (520) and

b. an inner portion adapted to accommodate an infill (530).

The envelope is characterized in that the envelope portion comprises a thermoplastic elastomer of a hardness between about 30 and about 60 Shore A and the inner portion is characterized in that the inner portion comprises a thermoplastic elastomer of a hardness between about 3 Shore A and about 15 Shore A, the infill comprising pressure maintaining fluid.

Reference is now made to fig 5 and 5a illustrating schematically a further embodiment of the invention wherein the surgical implant as described above is provided with anchoring means (510) for fixation within the synovial joint. The envelope thickness may vary in different embodiments of the invention.

Reference is now made to a further embodiment of the invention wherein the aforementioned surgical implant is adapted to assume a predetermined minimum thickness under compression. The thickness under compression is greater than about 1 mm and less than the thickness of the implant not under compression.

Reference is now made to a further embodiment of the invention wherein the aforementioned inner portion comprises silica gel.

Reference is now made to a further embodiment of the invention wherein the implant is adapted to be inserted via an artheroscope.

Reference is now made to a further embodiment of the invention wherein the envelope is adapted to be separately implanted into said synovial joint. The implant is further provided with an opening for post implantation introduction and withdrawal of inner portion or infill.

Reference is now made to fig. 6 illustrating schematically a further embodiment of the invention wherein the aforementioned implant further comprises at least one additional layer portion(620) disposed between the envelope portion (610) and the inner portion (630), further wherein the envelope further comprises a series of apertures for sustained release of medicines into the synovial joint.

Reference is now made to fig 7 &7a schematically illustrating a further embodiment of the invention wherein the envelope apertures are uni-directional valves (730), (750) adapted to facilitate controlled efflux of medicine (740) and preventing influx of synovial fluid. The layer (710) may be the medical substance bearing additional layer or alternatively, the inner core which may, in some embodiments release medicine via the outer envelope.

Reference is now made to a further embodiment of the invention wherein the medicines are at least one selected from a group consisting of narcotics, medicaments, hormones and local anti inflammatory drugs. The anti inflammatory drugs may be NSAID's or corticosteroids.

Reference is now made to a further embodiment of the invention wherein the envelope is porous or permeable and further wherein the inner portion or infill is adapted for storage and release of abrasive materials useful for reshaping synovial joint surfaces, the abrasive materials selected from a group consisting of diamond dust, aluminium oxide powders, salts, minerals, same diluted or suspended in mineral oil or solvents, such that the materials are released into the synovial joint at predetermined rates, quantities and intervals.

Biocompatibility

Biocompatibility is the ability of a material to perform with an appropriate host response in a specific application. (Williams, 1999) reference is now made to embodiments of the invention which may, at least in part, comprise biocompatible materials falling within any of the three following definitions:

Three definitions of biocompatibility

The ability of a material to perform with an appropriate host response in a specific application. - Williams' definition. The definition was defined in the European Society for Biomaterials Consensus Conference I

The quality of not having toxic or injurious effects on biological systems. - Dorland's Medical Dictionary, note that biocompatibility is defined as the absence of host response and does not include any desired or positive interactions between the host tissue and the biomaterials. Comparison of the tissue response produced through the close association of the implanted candidate material to its implant site within the host animal to that tissue response recognized and established as suitable with control materials- ASTM

All these definitions deal with materials and not with devices. This is a drawback since many medical devices are made of more than one material. Much of the pre-clinical testing of the materials is not conducted on the devices but rather the material itself. But at some stage the testing will have to include the device since the shape, geometry and surface treatment etc of the device will also affect its biocompatibility.

Suggested sub-definitions of biocompatibility

The scope of the first definition is so wide that D Williams tried to find suitable subgroups of applications in order to be able to make more narrow definitions. In the MDT article from 2003 the chosen subgroups and their definitions were:

Biocompatibility of long-term implanted devices

The biocompatibility of a long-term implantable medical device refers to the ability of the device to perform its intended function, with the desired degree of incorporation in the host, without eliciting any undesirable local or systemic effects in that host

Biocompatibility of short-term implantable devices

The biocompatibility of a medical device that is intentionally placed within the cardiovascular system for transient diagnostic or therapeutic purposes refers to the ability of the device to carry out its intended function within flowing blood, with minimal interaction between device and blood that adversely affects device performance, and without inducing uncontrolled activation of cellular or plasma protein cascades.

Biocompatibility of tissue-engineering products The biocompatibility of a scaffold or matrix for a tissue-engineering products refers to the ability to perform as a substrate that will support the appropriate cellular activity, including the facilitation of molecular and mechanical signaling systems, in order to optimize tissue regeneration, without eliciting any undesirable effects in those cells, or inducing any undesirable local or systemic responses in the eventual host.

In these definitions the notion of biocompatibility is related to devices rather than to materials as compared to top three definitions.

The critique against the Williams definition usually boils down to the fact that it is not possible to make a single test that determines whether a material is biocompatible or not. [citations needed] Indeed, since the hemostasis of the immune response and repair functions in the body are so complicated it would seem odd that one can make one test to determine the biocompatibility of any given material. Sometimes one hears of biocompatibility testing that is a large battery of in vitro test that is used in accordance with ISO 10993 to determine if a certain material (or rather biomedical product) is biocompatible. These tests do not determine the biocompatibility of a material, but they constitute an important step towards the animal testing and finally clinical trials that will determine the biocompatibility of the material in a given application, and thus medical devices such as implants or drug delivery devices.

Biocompatible material

In surgery, a biocompatible material (sometimes shortened to biomaterial) is a synthetic or natural material used to replace part of a living system or to function in intimate contact with living tissue. Biocompatible materials are intended to interface with biological systems to evaluate, treat, augment or replace any tissue, organ or function of the body. Biomaterials are usually non-viable, but may also be viable.

A biocompatible material is different from a biological material such as bone that is produced by a biological system. Artificial hips, vascular stents, artificial pacemakers, and catheters are all made from different biomaterials and comprise different medical devices.

Biomimetic materials are not made by living organisms but have compositions and properties similar to those made by living organisms. The calcium hydroxylapatite coating found on many artificial hips is used as a bone replacement that allows for easier attachment of the implant to the living bone.

Surface functionalization may provide a way to transform a bio-inert material into a biomimetic or even bioactive material by coupling of protein layers to the surface, or coating the surface with self-assembling peptide scaffolds to lend bioactivity and/or cell attachment 3-D matrix.

Different approaches to functionalization of biomaterials exist. Plasma processing has been successfully applied to chemically inert materials like polymers or silicon to graft various functional groups to the surface of the implant. Polyanhydrides are polymers successfully used as a drug delivery materials.

Biomimetic Coating

AVI's Biomimetic Coating was designed by polymer scientists at the University of Utah and clinical immunologists at Uppsala University. The surface coating is inspired by the body's natural healing mechanisms and the immune system's ability to recognize "self from "non-self. The design incorporates elements that prevent the inflammatory processes that lead to restenosis, while still providing a favorable surface for healing and regeneration of the endothelium. AVI's coronary stent coating has two parts. One part is a proprietary End Group Activated Polymer (EGAP). The EGAP surface technology transforms traditional device materials into biocompatible and thromboresistant surfaces and further enables the attachment of biologically active or therapeutic compounds. The second part of the coating is a protein called factor H, which interrupts the inflammatory processes that lead to restenosis.

Restenosis

Factors that lead to restenosis are introduced at the time of stent implantation when the endothelial lining and smooth muscle cells (SMC) in the artery wall are damaged. This insult and the presence of the metal stent trigger thrombus formation and complement activation, both of which cause activation of inflammatory cells. Activated inflammatory cells fuel the restenosis process by migrating into the artery wall and secreting mitogens. These in turn stimulate SMC growth and matrix production, which are the primary contributors to narrowing of the arterial lumen. Unlike restenosis after stent implantation, restenosis post angioplasty is due largely to elastic recoil with only a small contribution from neointima proliferation. Differences in the characteristics of restenosis after angioplasty and stent implantation at the molecular, cellular and macroscopic levels suggest that a foreign body response is a major contributor to the neointima formation after stenting and implicate complement activation as a cause of prolonged inflammatory stimulation.

EGAP Polymer

EGAP is a triblock copolymer that self assembles on surfaces and forms a thick brush-like layer of polyethylene oxide that acts as a protective shield to prevent protein adsorption, platelet activation, and thrombus formation. Based on proprietary end group activation chemistry, EGAP acts as a linker for binding factor H to the stent surface and allows for a high level of control over the amount of protein loaded onto the stent.

Factor H ,

Factor H is an important protein that regulates complement activation. This regulation occurs by multiple mechanisms which include disruption of C3 convertase formation and acceleration of its decay. Factor H also acts as a cofactor to factor I in the degradation of C3b, and competes with factor B for binding to C3b. Factor H can be produced recombinantly or isolated from human plasma by conventional fractionation techniques. With AVF s proprietary coating technology, factor H is covalently linked to stents through the activated end groups of the EGAP coating.

Advantages of AVI's Biomimetic Coating

The following schematic shows how AVI's coating is different from current drug eluting stents (DES). DES target the outcome of inflammation by preventing cell growth and migration. Cell growth and migration are important processes that are required for healing of the endothelium. A major advantage of AVI's Biomimetic coating is that it targets inflammation at an early stage, which does not impair healing.

Mechanism of Restenosis Summary of Advantages of AVFs Coating:

Prevents restenosis while supporting healing

Polymer component is biocompatible and thromboresistant

Very thin coating does not alter stent profile

Coating is securely bound to stent and does not crack, peel or form webs that may interfere with side branch flow with stent expansion

Aqueous based coating process is environmentally friendly

May eliminate need for longer term dual anti-platelet therapy

Since the EGAP - Factor H coating has demonstrated efficacy in preventing inflammation after implantation of stents, it is an object of the invention to provide implants coated with EGAP and EGAP like polymers linked to Factor H or Factor H like products.

It is envisaged and acknowledged that implants coated with EGAP linked to Factor H will have an anti - inflammatory effect on the joint, joint space and cartilage surfaces. It is well within the scope of the invention to provide embodiments of the implant coated with EGAP linked to Factor H to alleviate damaged joints. It is further well within the scope of the invention to provide implants releasing EGAP linked to Factor H compounds in a controlled and sustained manner into the joint space.

Use of gold salts for treating arthritis.

Gold salts describe ionic chemical compounds of gold. The term, which is a misnomer, has evolved into a euphemism for the gold compounds used in medicine. The application of gold compounds to medicine is called "chrysotherapy" and "aurotherapy."[l] The first reports of research in this area appeared in 1935,[2] primarily to reduce inflammation and to slow disease progression in patients with rheumatoid arthritis. Most chemical compounds of gold, including some of the drugs discussed below, are not in fact salts. Indications

Gold compounds, which accumulate slowly in the body and, over time, reduce inflammation, especially related to rheumatoid arthritis, inflammatory bowel disease, psoriatic arthritis, membranous nephritis, lupus erythematosus and, infrequently, juvenile rheumatoid arthritis (JRA).

The mechanism by which gold drugs operate to treat arthritis is a matter of scientific debate. Of the various mechanisms that have been suggested for the transportation of the drugs to their sites of action in the synovium, it is thought that in the blood stream the gold attaches to albumin. The thiol groups on the gold drug being exchanged for the cysteine cysteine-34 of this protein. After arrival at the synovium, the Au(I) again undergoes a second thiol exchange reaction at cell membrane transport proteins and enters the cell via the shuttle thiol mechanism. Once absorbed into the cell, gold is proposed to be linked to anti-mitochrondrial activity and induced cell apoptosis. The myriad of side effects associated with this class of prodrugs is ascribed to the nonspecific absorption and pharmacological action, thus many cells not linked with the Rheumatoid Arthritis immune response are affected. Some assert that gold drugs merely inhibit the function of the various components of the immune response associated with Rheumatoid Arthritis, rather than acting in a disease curing fashion. It is thought that gold affects the entire immune response (phagocytes, leukocytes, T-CeIIs...) and reduce its potency and limit its oxidizing nature, ending the cycle of joint inflammation and erosion.

At present, gold salts are infrequently used to treat children with Juvenile idiopathic arthritis (previously termed Juvenile Rheumatoid Arthritis), as methotrexate is the convention. Gold salts are sometimes used for children with progressive polyarthritis who are unresponsive to nonsteroidal anti-inflammatory drugs, methotrexate, and other medications. This treatment is expensive requiring frequent visits to the doctor and numerous lab tests. Administration

Gold drugs can be administered orally or by intramuscular injection, in which case it is administered weekly for approximately three to five months before less-frequent doses begin. Auranofin, in capsule form for oral administration, is marketed under the brand name Ridaura. Sodium aurothiomalate (Gold sodium thiomalate as brands Myocrisin UK, Aurolateor or Myochrysine U.S.) and aurothioglucose (Solganal in U.S.) are administered by injection. Regular urine tests to check for protein (indicating kidney damage) and blood tests are needed.

Efficacy

A 2005 review (Suarez-Almazor ME et al.) reports that treatment with intramuscular gold (parenteral gold) reduces disease activity and joint inflammation. Gold salts taken by mouth are less effective than by injection. Three to six months are often required before gold treatment noticeably improves symptoms.

A 2002 paper (Richards et al.) chronicles the neurological side effects of gold salts reported in the medical literature. "[T]here are reports pointing to a possible involvement of naturally- occurring gold in the nervous and glandular systems, and evidence from historical sources of a possible efficacy of gold in therapy for neurological disorders," according to the study authors. "This research has the potential for re-establishing gold as a significant therapeutic agent in a much wider range of disorders than those for which it is currently used. And it could help in sorting out valid from invalid claims of benefits from supplementation."

Side effects

Side effects may develop after a significant accumulation of gold in the body. Gold compounds require up to two months to reach a steady state, and have a fairly long half life. In 10 days, only 70% is excreted, exacerbating toxicity problems. The potential benefits for patients with inflammatory bowel disease, skin rash or a history of bone marrow depression should be weighed against the potential risks of gold toxicity on previously compromised organ systems or with decreased reserve. Potential problems with detection and correct attribution of toxic effects must also be considered.

Orally administered gold has fewer side effects than intramuscular injections. Common side effects of oral gold include decreased appetite, nausea, hair thinning and diarrhea, as well as problems affecting skin, blood, kidneys, or lungs. Common side effects of injected gold include an itchy skin rash or mouth sores, with rare instances of kidney problems or suppression of blood cell production.

It has been suggested in Japan that gold salts used for the treatment of Rheumatoid Arthritis particularly gold thioglucose, may also be used for the treatment of bronchial asthma.

There are several types of gold salts used in medicine and some or all of these are used in some embodiments of the invention.:

Auranofin (UK & U.S.)

Aurothioglucose (Gold thioglucose) (U.S.)

Disodium aurothiomalate

Sodium aurothiosulfate (Gold sodium thiosulfate)

Sodium aurothiomalate (Gold sodium thiomalate) (UK)

GENERIC NAME: aurothioglucose

BRAND NAME: Solganal

DRUG CLASS AND MECHANISM: Aurothioglucose is a gold salt used in treating inflammatory arthritis. In patients with inflammatory arthritis, such as adult and juvenile rheumatoid arthritis, gold salts can decrease the inflammation of the joint lining. This effect can prevent destruction of bone and cartilage.

It is herein acknowledged that embodiments of the invention include a surgical implant such that the implant further comprises at least one additional layer portion disposed between the envelope portion and the inner portion, further wherein the envelope further comprises a series of apertures for sustained release of medicines into said joint space. It is yet further acknowledged that the aforementioned medicines may comprise at least one selected from a group consisting of narcotics, medicaments, hormones, local anti inflammatory drugs, gold salts and salts other than gold salts.

It is yet further acknowledged that the aforementioned gold salts may comprise at least one selected from a group consisting of Auranofin ,Aurothioglucose ,GoId thioglucose ,Disodium aurothiomalate ,Sodium aurothiosulfate ,GoId sodium thiosulfate, Sodium aurothiomalate, Gold sodium thiomalate Aurothioglucose and Solganal

More information on the use of gold salts for relieving arthritic conditions are found in the following publications which are incorporated by reference in their entirety :Emery P, Suarez- Almazor M (2002). "Rheumatoid arthritis". Clinical Evidence (10): 1454-1476. PMID 12230730.

Kwoh CK, et al. (2002). "Guidelines for the management of rheumatoid arthritis". Arthritis and Rheumatism, 46(2): 328-346. PMID 1 1840435.

Petiot P, Charles N, Vial C, McGregor B, Aimard G, Trillet M, Bady B. Rev Neurol (Paris), "Neurological complications caused by gold salts. Nosologic report apropos of a case" (article in French). 1993;149(10):562-5. PMID 7912843.

Richards DG, McMillin DL, Mein EA, Nelson CD. Gold and its relationship to neurological/glandular conditions. Int J Neurosci 2002; 1 12:31-53. Meridianlnstitute.com PMID 12152404.

Suarez-Almazor ME, Bennett KJ, Bombardier C, Clark P, Shea BJ, Tugwell P, Wells G, - 'Injectable gold for rheumatoid arthritis¹, Cochrane Review (2005) Cochrane.org PMID 10796386

Near-infrared (NIR) spectroscopy Near infrared spectroscopy (NIRS) is a spectroscopic method utilising the near infra-red region of the electromagnetic spectrum (from about 800 nm to 2500 nm). Pharmaceutical, medical diagnostics (including blood sugar and oximetry are among it's applications. It is commonly used for medical diagnostics, in particular for oximetry (the measurement of oxygen levels in the blood) and for blood sugar determination.

Use of NIR in diagnosis of cartilage lesions.

The following is included by way of reference to the rationale wherein some embodiments of the implant will include means for carrying, housing and /or accommodating a NIRS probe within the joint space for monitoring processes occurring within the joint space environment.

A new method for arthroscopic evaluation of low grade degenerated cartilage lesions.

Results of a pilot study (Spahn et al)l Center of Traumatology and Orthopaedic Surgery, Sophienstr. 16, 99817 Eisenach, Germany

BMC Musculoskeletal Disorders 2007, 8:47doi:10.1186/1471-2474-8-47

Published: 29 May 2007

Background

Arthroscopy is a highly sensitive method of evaluating high-grade cartilage lesions but the detection of low-grade lesions is often is unreliable. Objective measurements are required. A novel NIRS (near-infrared-spectroscopy) device for detection of low-grade cartilage defects was evaluated in a preliminary clinical study.

Methods

In 12 patients who had undergone arthroscopy, the cartilage lesions within the medial knee compartment were classified according to the ICRS protocol.

With a NIR spectrometer system and an optical probe, similar in design to a hook used for routine arthroscopy, the optical properties of cartilage were measured during arthroscopy. Results

The mean ratio of 2 NIR absorption bands of intact cartilage 3.8 (range 2.3 to 8.7).was significantly lower than that of cartilage with grade 1 lesions (12.8, range 4.8 to 19.6) and grade 2 lesions (13.4, range 10.4 to 15.4).

No differences were observed between grade 1 and grade 2 lesions.

Conclusion

NIRS can be used to distinguish between ICRS grade 1 lesions and healthy cartilage during arthroscopic surgeries. The results of this clinical study demonstrate the potential of NIRS to objectify classical arthroscopic grading systems.

Research article

Near-infrared (NIR) spectroscopy. A new method for arthroscopic evaluation of low grade degenerated cartilage lesions. Results of a pilot study

Gunter Spahn et al,Center of Traumatology and Orthopaedic Surgery, Sophienstr. 16, 99817 Eisenach, Germany

BMC Musculoskeletal Disorders 2007, 8 :47doi:l 0.1186/ 1471-2474-8-47

Published: 29 May 2007

Background

Methods In 12 patients who had undergone arthroscopy, the cartilage lesions within the medial knee compartment were classified according to the ICRS protocol.

With a NIR spectrometer system and an optical probe, similar in design to a hook used for routine arthroscopy, the optical properties of cartilage were measured during arthroscopy.

Results

No differences were observed between grade 1 and grade 2 lesions.

Conclusion

Background

Cartilage degeneration is associated with complex changes in cartilage matrix composition that result in decreased collagen and proteoglycan content and increased water content. These changes in matrix composition correlate with decreased mechanical stiffness. As a result, four stages of cartilage lesions develop. The consensus conference of the ICRS I (international Cartilage Repair Society) suggested a score for cartilage lesions in 2002 [I]: The grades were as follows: ICRS grade 0 (normal), ICRS grade 1 (nearly normal, superficial lesions with soft indentation and/or superficial fissures and cracks), ICRS grade 2 (abnormal, lesions extending down to <50% of cartilage depth), ICRS grade 3 (severely abnormal, cartilage defects extending down > 50% of cartilage depth) and ICRS grade 4 (severely abnormal, complete defect).

Clinical examination (crepitus, effusion and pain) is nonspecific. Radiological signs of osteoarthritis (joint space narrowing, subchondral sclerosis, osteophytes) are primarily associated with high-grade cartilage damage, and are therefore inadequate for diagnosing early disease stages.

The diagnosis of cartilage lesions can be made by MRI or arthroscopic evaluation. MRI is the most important non-invasive diagnostic method for assessing cartilage lesions. Many studies have demonstrated the high validity of MRI for evaluating chondral lesions in the knee as well as in other joints, but MRI has low accuracy for initial lesions. Only specific techniques like dGEMRIC (delayed Gadolinium Enhanced MRI of Cartilage) are sufficient for evaluating initial chondral lesions.

The arthroscopic diagnosis of chondral lesions depends on the surgeon's subjective rating alone. Diagnosis is made by visualizing the lesion on the video monitor and by probing with the arthroscopy hook.

Friemert et al. [5] found a good correlation between MRI and arthroscopic findings in the case of deep cartilage lesions. One criterion for the validity of arthroscopic diagnosis is the "inter- observer-validity". The diagnosis of deep cartilage defects has high validity but the diagnosis of low grade lesions is often inaccurate [6-11]. Detection of these early stages primarily involves palpation with the arthroscopic hook. This palpation depends on the power applied by the manual pressure of the surgeon and, as Li and Herzog demonstrated, on the geometry of the distal end of the hook [12].

Recent studies have used mechanical devices to attempt to measure cartilage softening objectively by evaluating the reduced stiffness of the cartilage [13-17]. Duda et al. created an instrument for stiffness measurements in a "low-contact-modus". The reduction of cartilage stiffness was measured as a function of surface deformation produced by a pulsed flow [18]. However, the practical use of these instruments is limited by their dimensions. Furthermore, the necessity of positioning these instruments exactly vertical to the cartilage surface may limit their practical use in routine arthroscopy.

Early disease stages are characterized by a rise in the water content of the extracellular matrix and, as a result, cartilaginous swelling [19-23]. The water inflow strongly correlates with the loss of mechanical stiffness [24]. In the last decade NIRS (near-infrared-spectroscopy) became an important method for analyzing materials with complex mixes of chemical substances [25], in particular for measuring the water content of the material In a recent ex vivo study Spahn et al. [26] demonstrated a decrease of NIR-absorption in low-grade degenerated cartilage. The decreased NIR absorption did correlate with an increase of water content in early degenerated cartilage.

This study introduces a novel NIRS-device that is capable of identifying low-grade cartilage lesions under arthroscopic control.

Methods

Patients

All patients gave informed consent and agreed to participate in the study. This study was approved by the regional Ethics Committee (Jena, RZ 714-0110).

Twelve patients were selected who had been suffering from knee pain for more than 3 months and had undergone arthroscopic evaluation. There were 7 male and 5 female patients. The patients were 31.1 ± 6.7 years old (range 25 to 45). No patient had suffered from an injury. No patient had undergone other prior surgery. All patients had a non-traumatic medial meniscus tear and had undergone partial meniscectomy during arthroscopy.

Preoperative Imaging

The preoperative diagnosis was made by clinical examination, radiography and MRI. All patients had suffered from knee pain and demonstrated clinical signs of medial meniscus tears. No patient had radiological signs of osteoarthritis on standard x-ray [27].

The cartilage defects were graded by MRI according to Vallotton et al. [28]. No patient had abnormal MRI findings in the lateral compartment or within the femoropatellar joint. The evaluations of the radiographs and MRI scans were performed by author EK.

Arthroscopic evaluation All operations were performed under general anesthesia by using a tourniquet. The tourniquet was placed halfway between the knee and hip. A standard 0.9 % sodium chloride solution was used for irrigation. A lavage (p = 80 mmHg, flow = 100 ml/min) was performed for exactly 3 minutes before NIR measurements to remove any joint effusion.

The arthroscopic evaluation began with visualization of all joint compartments and included palpation with an arthroscopic hook. The cartilage defects were graded according to the ICRS protocol [1] by visualization and probing with an arthroscopic hook : ICRS grade 0 (normal), ICRS grade 1 (nearly normal, superficial lesions with soft indentation and/or superficial fissures and cracks), ICRS grade 2 (abnormal, lesions extending down to <50% of cartilage depth.

The ICRS grade classifications were determined independently by author MK, whereas the NIR measurements were performed independently by GS. Both are experienced arthroscopic surgeons who have performed more than 10.000 knee arthroscopies.

NIR spectroscopic evaluation

After routine arthroscopic evaluation the medial femoral condyle and the medial tibial surface within the medial bearing zone.and within the non- weight-bearing margin were examined with a NIR probe

NIRS for evaluation of cartilage lesions. Light from a stabilized light source was coupled into six optical fibers. The collection fiber (silica glass, 200 μm diameter) was connected to the spectrometer. The fibers were combined in a reflection-probe with the light delivering fibers surrounding the collection fiber. The design of the probe was similar to a routine arthroscopic hook. The intraoperative measurements were performed by using the probe in the same way as a hook. The top of the hook shows the end of the optical fibers.

The main components of the NIR spectrometer system were a diode micro-spectrometer (microparts, Dortmund, Germany) with a spectral range of 1100 nm to 1700 nm and spectral resolution of approx 16 nm, a stabilized light source (LQ2NIR, JETI Technische Instrumente GmbH, Jena, Germany) and a fibre optical reflection probe (Loptec, Berlin, Germany) with six fibers (silica glass, 200 μm diameters) for illumination surrounding one collection fibre (silica glass, 200 μm diameter)[26]. The probe's design is similar to that of a hook used for routine arthroscopy. The whole NIR spectrometer system (optical and electrical parts) is in accordance with the German law for medical products (Medical Device Directive (MDD) 93/42/EEC) [29].

Prior to each NIR measurement a reference spectrum was recorded in the irrigation solution within the superior recessus. Then the tip of the probe was placed on the cartilage surface in the region of interest and 10 NIR reflection spectra (cartilage spectrum) per second were recorded continuously. A total of 50 spectra were taken per region and averaged. Absorption spectra were then calculated [absorption spectrum = -loglO (cartilage spectrum/reference spectrum). The ratio (R) of the peak absorptions of two bands (the 1st OH and CH combination overtones (1340 nm - 1475 nm) and the 2nd CH overtone (1 150 nm - 1220 nm) was calculated for statistical evaluation. This ratio (absorption at 1425 nm/absorption at 1175 nm) represents the relative proportion of water to organic substances and can therefore be regarded as an indicator of the water content within the cartilage [29]. Evaluation of NIR measurements was completed independently by author HP.

Statistical analysis

The results of every diagnostic tool were blinded before final evaluation.

Statistical analyses were performed on a personal computer using SPSS (13.0), SPSS Inc., Chicago Illinois. After testing for normal distribution and variance homogeneity, a One- Way Analysis of Variances (ANOVA) and post - hoc pairwise comparison of means were preformed. The Pearson correlation coefficients were used to examine the relationships between the parameters. A p value < 0.05 was considered significant.

Results

Radiography and MRI evaluation

No patient showed any signs of osteoarthritis in standing radiographs. The width of the joint space did not correlate with intra-articular findings or with the BMI.

Results of preoperative imaging In routine MRI ICRS grade 0 cartilage was correctly classified 15 times, but grade 0 lesions were overestimated 13 times. Grade 1 lesions were correctly judged 13 times and underestimated 1 time. Of the grade 2 lesions, two defects were correctly classified but 3 were underestimated (table 2).

There was no correlation of BMI with the width of the joint space in standing radiographs (R = - 0.232, p = 0.469). The width of the joint space also did not correlate with the grade of cartilage lesions (R = 0.225, p = 0.482).

Arthroscopic findings

A serious effusion (more than 10 ml) was detected in 4 patients and 3 patients had a mild synovialitis. The distribution of cartilage lesions within the medial joint compartment is shown in figure 2. Cartilage lesions within the mean weight-bearing zone were significantly higher graded than in the margin (p = 0.027). No patient had cartilage lesions within the patello-femoral or lateral joint compartment. All patients had suffered a medial meniscus tear that required partial meniscectomy

Distribution of cartilage lesions.

Reference spectra in NIRS

The mean reference spectra recorded from saline irrigation solution within the superior recessus totaled 124.7 ± 27.8 Counts. No differences were identified between this control and joint effusions (p = 0.298) or synovialitis (p = 0.166).

Evaluation of low grade cartilage lesions by NIR spectroscopy

The ratio (R) of NIR absorption (AU@1425 nm/AU@l 175 nm) within intact cartilage was 3.8 ± 1.2 (range 2.3 to 8.7). In cartilage lesions it was significantly higher than in intact cartilage, (p = 0.000, table 3) with values for grade 1 lesions of 12.8 ± 4.8 (range 4.8 to 19.6) and for grade 2 lesions of 13.4 ± 2.1 (range 10.4 to 15.4).

Results of NIRS for evaluating cartilage lesions No differences in R were observed between grade 1 and grade 2 lesions (p = 0.828).

R depended on the grade of cartilage lesions but not on the area of measurement (p = 0.244),.

Results of NIRS probing within the cartilage surfaces of the medial joint compartment. The ratio of NIR absorption (R) within grade 1 lesions was significantly higher than in intact cartilage.

There were no differences in R between male and female patients (p = 0.057) and no correlations to the patient's age (p = 0.282).

Validity of MRI and NIRS in evaluation of initial cartilage lesions

The cartilage lesions in a total of 48 regions were evaluated by MRI, arthroscopy and NIRS. The arthroscopic diagnosis made by a "highly experienced" arthroscopic surgeon was defined as the diagnostic standard for the cartilage lesions.

In routine MRI the ICRS grade 0 cartilages were classified correctly 15 times, but grade 0 lesions were overestimated 13 times. Grade 1 lesions were correctly judged 13 times and underestimated 1 time. Of the grade 2 lesions, 2 defects were correctly classified but were underestimated 3 times.

The "normal-value [mean ± 2 SD]" of R for intact cartilage was 1.4 to 6.2. The 27 normal cartilages (grade 0) had values of R within the normal value excepting one outlier with a higher R. The values of R were always higher for cartilage lesions than for intact cartilage. NIRS has a significantly (p = 0.000) higher accuracy (0.979) than MRI (0.708).

Validity of MRI and NIRS in evaluation of low-grade cartilage lesions

Though NIRS and MRI show a similar sensitivity (1 and 0.95), NIRS has a significantly (p = 0.000) higher specificity (0.96) and accuracy (0,98) than MRI (0.54 and 0.70 respectively).

Discussion This study reports the possibility of using NIRS for objective identification of low-grade cartilage lesions during routine arthroscopy. We hypothesized that complex changes in cartilage matrix composition are reflected by changes in chondral optical properties in the NIR region.

The diagnosis of cartilage lesions can be made by MRI as well as arthroscopic evaluation. MRI using "routine sequences" has good validity for diagnosis of deep cartilage lesions. In contrast it is relatively inaccurate for evaluation of low grade lesions or validation of intact cartilage [28- 36].

Our results confirm this. Our MRI scans had excellent sensitivity for low grade cartilage lesions (0.950) but poor specificity (0.536).

In the future, special MRI techniques for cartilage lesions like d-Gemric (delayed Gadolinium Enhanced MRI of Cartilage) may improve the quality of these evaluations.

The arthroscopic evaluation of cartilage lesions is the current "gold standard". In standard arthroscopy cartilage lesions are graded using semiquantitative scores (eg Outerbridge classifications, ICRS score or others) [1,37,38]. The validity of this evaluation depends on the surgeon's experience. High-grade lesions are relatively obvious but the diagnosis of low-grade lesions is often difficult. Thus, other investigators have used mechanical stiffness measurements for evaluating softening in low-grade cartilage degeneration. However, the necessity of placing the stiffness probe exactly vertical to the chondral surface is disadvantageous [39] and can introduce difficulty during arthroscopic operations.

NIRS offers the possibility of evaluating changes in material composition [25]. Since water has a particularly high NIR absorption, NIRS is able to analyze water content in composite materials.

In the present study probes curved and dimensioned like a normal arthroscopic hook were used to record NIR reflection spectra of cartilage. It was therefore possible to reach all regions of interest without difficulty. The handling of the probe is easy, with measurement times of approx. 5 s per region. Probes can be sterilized like any other arthroscopic instruments. In contrast to histological, pathological, biochemical and mechanical measurements NIRS is a completely nondestructive method. By using NIRS the surgeon can distinguish between healthy and low-grade cartilage lesions, but not between high-grade lesions. This may be due to the fact that a water inflow is characteristic of the initial phase of degeneration but not of more advanced stages of chondral disease. Furthermore, at higher grades of degeneration the surface of cartilage becomes irregular, disturbing the collection of reflection spectra. Thus NIRS is restricted to detection of lower grade cartilage damage. Future investigations may identify NIR equipment and bands that can be used to characterize cartilage lesions with higher grades, although such lesions are easily detected by visualization even by relatively inexperienced surgeons.

Although the cartilage lesions were graded by a highly-experienced arthroscopic surgeon (MK), these grades are still subjective and therefore stand as the principal point of critique in our study. In contrast, the NIRS evaluations were made independently from the standard cartilage grading. The high concordance between arthroscopic grading and NIRS may favor this technique for future use in arthroscopy.

Conclusion

Our results suggest that NIRS could become an adequate method for arthroscopic differentiation of healthy and low-grade degenerated cartilage in future. Of course this is a preliminary study in only 12 patients. Because the study was aimed to check the principle of NIR measurements in cartilage evaluation, the clinical relevance of the cartilage lesions wasn't evaluated. In future larger series with independent investigators are required. NIRS measures the complex changes in the composition of low-grade degenerated cartilage. Thus it is possible that this method can be used routinely in arthroscopy in the future.

Abbreviations

ANOVA Analysis of Variances

d-Gemric delayed Gadolinium Enhanced MRI of Cartilage

ICRS International cartilage repair society

MRI Magnetic resonance imaging NIR Near infrared

NIRS Near infrared spectroscopy

Use of NIS for Diagnosis of Acute Compartment Syndrome.

Description: OTA 2002 - Session 1 Session I - Combined Session (International Society for Fracture Repair) FrL, 10/11/02 Combined Session, Paper #8, 9:12 AM *Near Infra-red Spectroscopy in the Diagnosis of Acute Compartment Syndrome Matthew J. Hope, MRCSE ; Carol Hajducka, RN; Hamish Simpson, MD; Margaret M. McQueen, MD, FRCS; Royal Infirmary of Edinburgh, Edinburgh, United Kingdom (a-Hutchinson Technology) Purpose: Near- infrared spectroscopy (NIRS), which measures soft tissue oxygenation (StO 2 ) noninvasively, is potentially a new noninvasive technique for the early detection of acute compartment syndrome (ACS). Animal models of ACS have shown that StO 2 correlates with perfusion pressure in the compartment. The first part of this study examined intracompartmental pressure and StO 2 among patients at risk of ACS. The second part investigated the influence of subcutaneous and intramuscular hematoma on NIRS in an ACS animal model. Methods: 1) Adult patients with tibial or radial diaphyseal fracture or gross soft tissue swelling were recruited on admission to the orthopaedic trauma unit. Noninvasive and invasive monitoring were carried out from admission until a minimum of 24 hours postoperatively. The differential pressure (DDP) was calculated as the compartment pressure subtracted from the diastolic blood pressure. The threshold for fasciotomy was a 'DDP' <30mmHg. StO 2 values were simultaneously recorded from the contralateral (uninjured) limb at the same site. The difference between the StO 2 value on the injured and uninjured sides was calculated (StO 2 difference). 2) Fifteen adult pigs were divided into three equal groups: plasma infusion alone, plasma infusion with SC hematoma (15 ml of blood) and whole blood infusion (intramuscular hematoma). An ACS was induced under general anesthesia by the above infusion into the anterior compartment of one rear leg of each animal. On both legs noninvasive StO 2 and compartment pressure monitoring were carried out. The development of an ACS was confirmed by absence of muscle twitch on electrical stimulation. Fasciotomy was performed 30 minutes later. DDP and 'StO 2 difference' (calculated as above) were compared. Results: 1) Three patients with thigh swelling, 73 with tibial fracture, and 2 with forearm fracture were recruited. Mean 'StO 2 difference' (%) Mean 'DDP' (mmHg) no fasciotomy ( N = 59) 10.0 P = 0.003 52.6 P < 0.001 fasciotomy ( N = 18, all leg) -2.7 24.5 2) An acute compartment syndrome was confirmed in all animals. Correlation between DDP (mmHg) and 'StO 2 difference' (%) Plasma infusion ( N = 5) r = 0.754 P = 0.01 Plasma infusion + SC hematoma ( N = 5) r = 0.004 P = 0.95 Intramuscular hematoma ( N = 4) r = 0.516 P = 0.01 Discussion/Conclusion: The StO 2 difference (measured noninvasively) was significantly lower among patients with an ACS, suggesting that NIRS can detect decreasing tissue oxygenation in trauma patients who are developing an ACS. The animal study confirms a strong correlation between DDP (mmHg) and StO 2 difference (%) in a plasma infusion and an intramuscular hematoma model. This correlation was lost in the presence of a SC hematoma. We are optimistic that NIRS will prove to be a reliable new noninvasive technique for the early detection of an acute compartment syndrome. The localization and avoidance of areas of SC hematoma will improve the diagnostic accuracy of NIRS in acute compartment syndrome.

It is acknowledged herein that means and methods are provided for NIRS monitoring of the internal state of a joint space and of a synovial joint space. The inner portion of the implant is provided with an internal NIRS sensor unit. This sensor receives power and or transmits data concerning the internal state of a joint space and of a synovial joint space via a tube extending from the implant outward to a subdermal location which can be opened when necessary for connecting to a power supply and or the data recording device or monitor.

It is moreover acknowledged herein that a further means and method is provided for NIRS monitoring of the internal state of a joint space and of a synovial joint space. The inner portion of the implant is provided with an internal NIRS sensor unit, which has its own internal or adjacent power supply and is further adapted to reside in the implanted implant, and monitor the surrounding tissue and cartilage from within the joint space. The NIRS sensor unit can record data for subsequent study upon withdrawal from the implant and joint space via the communicating tube. Other embodiments of the invention are envisaged wherein the NIRS sensor unit is provided with means for wirelessly transmitting data from within the joint space to an external monitor.

It is acknowledged herein that biocompatible and biodegradable materials which can be used to comprise at least part of the implant may be selected from the following non limiting list: Polylactic acid (PLA), Polyglycolic acid (PGA), Polycaprolactone (PCL) , Polydioxanone (PDO or PDS) PLGA or poly(lactic-co-glycolic acid) Polyhydroxybutyrate (PHB) Poly-3- hydroxybutyrate (P3HB)

(PLGA is a combination of the cyclic dimers (l,4-dioxane-2,5-diones) of glycolic acid and lactic acid).

It is further acknowledged that some embodiments of the invention may comprise at least in part of Nitinol or other shape -memory material.

It is further acknowledged that some embodiments of the invention may comprise at least in part of Electo Active Materials.

Reference is now made to a further embodiment of the invention wherein the envelope is porous and further wherein the additional layer is adapted for storage and release of abrasive materials useful for reshaping synovial joint surfaces, the abrasive materials selected from a group consisting of diamond dust, aluminium oxide powders, salts, minerals, all said same diluted or suspended in mineral oil or solvents, such that said materials are released into the synovial joint at predetermined rates, quantities and intervals.

Reference is now made to a further embodiment of the invention wherein any of the portions of the infilled member comprise radio-opaque material useful for positioning the implant or monitoring the health status of the joint.

Reference is now made to a further embodiment of the invention wherein the infill is selected from a group consisting of solid material, nano powders or micro powders

Reference is now made to a further embodiment of the invention wherein the infill is a fluid.

Reference is now made to a further embodiment of the invention wherein the aforementioned fluid is selected from a group consisting of a liquid, gas, gel, emulsion, diluted solution, heterogenous solution, aggregates or liposomes. It should be noted that the aforementioned gas is preferably carbon dioxide. Reference is now made to a further embodiment of the invention shown in fig 8 wherein the implant comprises vertical (810) or horizontal compartments (horizontal compartments not shown).

Reference is now made to a further embodiment of the invention wherein the implant is adapted for insertion into the synovial space of joints of a human body, the joints selected from a group consisting of knee joint, ankle joint, shoulder joint ,hip joint, palm joint and spinal joints.

Reference is now made to a further embodiment of the invention wherein the implant is adapted for accommodating a video capsule of the GI type for monitoring the internal synovial joint environment.

Reference is now made to a further embodiment of the invention wherein the implant is adapted for accommodating an externally powered video camera. Reference is now made to fϊg.9 schematically illustrating the aforementioned implant additionally provided with a tube(910) extending from the implant outward to a subdermal location for communicating with the external power supply of the camera. Some embodiments of the invention are provided with a diagnostic window, hatch , flap or door (930) as schematically illustrated in fig 9 for observation, sampling or tool manipulation.

Reference is now made to fig. 9 illustrating a further embodiment of the invention wherein the tube(910) is adapted for accommodating a fibre optic external light source for illumination of the synovial joint. It will be appreciated that the opening of the tube sits just below the skin surface, sub- dermal Iy, and therefore it can be used to effect passage of materials in and out of the implant.

Reference is now made to a further embodiment of the invention wherein the tube is adapted for injecting or removing fluids, especially medicaments, powders, dyes or infill.

Reference is now made to a further embodiment of the invention wherein the tube is provided with a multiplicity of lumens, each lumen adapted for mediating specific functions selected from a group consisting of power supply, illumination, inner portion pressure control and adjustment, administration of medicaments, drainage of said implant, external video monitoring, administration of therapies, and withdrawal of biopsy samples. Reference is now made to a further embodiment of the invention wherein the inner portion of the implant is provided with means for providing therapeutic vibrations. In fact, the implant is thus a vibrating effector.

Reference is now made to a further embodiment of the invention wherein the inner portion is provided with heating means. In such a case, the implant is thus a heating effector.

Reference is now made to a further embodiment of the invention wherein the above mentioned heating means is a peltier device.

Reference is now made to a further embodiment of the invention wherein the inner portion of the implant is provided with cooling means. In such a configuration, the implant is thus a cooling effector.

Reference is now made to a further embodiment of the invention wherein the cooling means is a peltier device or a saline circulation system.

Reference is now made to a further embodiment of the invention wherein the aforementioned inner inner portion is adapted to be inflated and deflated. The inner inner portion can be inflated with gas or fluid via a lumen in the tube. It is herein acknowledged that pumping in (inflating) or withdrawal (deflating) of fluid or gas into the implant can be done before, during or after the artheroscopic procedure. It is herein acknowledged that the removal of fluids, gases, medicaments , abrasive materials, biologically active materials, and biologically inert materials may be carried out at predetermined times according to physician or health worker protocols during the period of residence of the implant within the synovial joint, according to the needs of the patient and the progress of the synovial regeneration process.

Reference is now made to a further embodiment of the invention wherein the envelope portion is provided with filtration means.

Reference is now made to a further embodiment of the invention wherein envelope portion is provided with a diagnostic window. It is herein acknowledged that such a window facilitates monitoring of the health status of the synovial joint in real time. Reference is now made to a further embodiment of the invention wherein said implant is of dimensions such that a plurality of said implants can be stacked either vertically or horizontally in synovial space. Such stacking allows the physician to remove or add additional implants as required during the course of treatment.

The implant is removable from the knee after the healing period. Specific pressure on knee cartilage is lessened due to uniform distribution over the cartilage surface. The implant embodies a specially coated padding softening mechanical contact between the implant and the knee cartilage. Additionally, the aforesaid implant can be adapted for shaping the cartilage during the healing period. A flexible casing of the implant can be formed for shaping recovered cartilage.

Prolotherapy

Prolotherapy involves the injection of an irritant solution into the area where connective tissue has been weakened or damaged through injury or strain. Many solutions are used, including Dextrose, Lidocaine (a commonly used local anesthetic), Phenol (an alcohol), Glycerine, or Cod Liver Oil extract. The injection is given into joint capsules or where tendon connects to bone. Many points may require injection. The Injected solution causes the body to heal itself through the process of inflammation and repair. In the case of weakened or torn connective tissue, induced inflammation and release of growth factor at the site of injury may result in a 30-40% strengthening of the attachment points. Some embodiments of the invention are herein disclosed wherein the implants comprise at least one additional layer portion disposed between said envelope portion and said inner portion, wherein the envelope further comprise a series of apertures for sustained release of medicines into the joint space.

Intraarticular Fracture

Intraarticular fractures are those in which the break crosses into the surface of a joint extending to the articular surface of the bone.

Such fractures always result in some degree of cartilage damage. In addition to the usual considerations in fracture management, the relative position of the bone fragments and their relationship to ligament attachments are critical. Ideally, the joint surfaces should be restored to their original position and held there strongly enough that movement may be started in the early postoperative period. This is not always technically possible, and some cases cannot be helped by the most skillful surgery. Some permanent loss of motion is to be expected and the joint may develop degenerative arthritis as a result of the injury. In addition, possible long term problems include presence of a palpable or visible bony prominence, deformity, numbness, weakness, reflex sympathetic dystrophy and others. Less likely problems include re-fracture, compression neuropathy and tendon rupture. Surgical treatment of the fracture may be indicated when the potential risks of surgery are felt to be justified by the potential benefits of improving the alignment of the bones as they heal. Hardware may be required to hold the fracture fragments in position. Even with surgery, the fracture is still prone to the problems noted above in addition to risks of surgery, such as infection, hardware related problems, numbness, tender scars, residual deformity, as well as less common problems such as anesthetic or drug related reactions, among others. Fracture position may shift even after reduction, internal fixation and immobilization. Future removal of hardware may be required. This type of injury may result in degenerative arthritis. Embodiments of the invention useful for treating intra articular fractures are provided in general .According to L S Lohmander et al.( Annals of the Rheumatic Diseases 1996;55:424-431) intra- articular hyaluronan injections may be efficacious in an knee which has developed osteoarthritis following intraarticular fracture. Certain embodiments of the implant allow controlled delivery of intra-articular hyaluronan to a knee which has developed osteoarthritis following intraarticular fracture via the implant, thereby avoiding the use of injections and increasing efficacity. Still other embodiments for treating intra articular fractures of the knee are implants delivering gold salts. Still other embodiments of the invention are implants for treating intra articular fractures of the knee and other joints, adapted to deliver NSAIDs (Non-Steroidal Anti-Inflammatory Drugs), steroid agents such as glucocorticoid and/or hyaluronic agents, for example, synvisc or hyaluronan. some embodiments of the aforesaid implants also has a reshaping function due to the implants surface which is provided with a raised textured external surface, or a surface comprising treads, bumps, indentations, nipples, roughenings or a combination thereof. Fig9 schematically illustrates an embodiment of the implant used for treating intra articular fractures adapted for accommodating an externally powered video camera (940), the implant additionally provided with a communicating tube (910) extending from said implant outward to a subdermal location for communicating with the external power supply of said camera. More specifically it is herein acknowledged that in some embodiments of the invention devices and methods useful for treating Interarticular - fractures in the knee, ankle, elbow, shoulder, foot, wrist or hand. Some of these embodiments are adapted to release narcotics, medicaments, Cell Density Signal-1, CDS-I ,dextrose, glycerin hormones, local anti inflammatory drugs, gold salts and salts other than gold salts.

It is herein acknowledged that in some embodiments of the invention devices and methods are adapted for repairing damaged tendons

It is herein acknowledged that in some embodiments of the invention devices and methods are adapted for repairing damaged nerves

It is herein acknowledged that in some embodiments of the invention an implant is provided useful for repairing a tendon where there is loss of cartilageor a depression.

ALLOPLASTIC NERVE GRAFTS Permanent conduit materials

Silicone is a permanent conduit material that has been used for nerve grafting. However, long- term tubulization of a nerve produces localized compression with resultant decreased axonal conduction, although total number of nerve fibers and axon size remain constant. Alterations in the blood-nerve barrier occur, followed by demyelination of the nerve fibers (19, 20). Silicone tubes used for neural conduits must be removed to achieve apositive outcome (21). Similar unfavorable outcomes have been seen when using Gore-Tex vein grafts (WL Gore and Associates, Inc, Flagstaff, Ariz) as a nerve graft conduit (22, 23). The clinical studies indicated that Gore-Tex (polytetrafluorethylene) tubing is not effective and therefore not recommended in the repair of continuity defects of IAN and LN.

Synthetic resorbable conduits

Polyglycolic acid (Dexon, American Cyanamid Co, Wayne, NJ) is a bioabsorbable substance that is currently used as a suturematerial (24) and in mesh form to wrap internal organs injured as a result of trauma (25). It is absorbed in the body by means of hydrolysis within 90 days of implantation (26, 27).

A bioabsorbable polyglycolic acid conduit has been developed for nerve grafting (Neurotube, Neurogen LLC, Bel Air, Md) and was approved by the Food and Drug Administration for human use in 1999 (Figure 3). Characteristics of this tube include 1) porosity, which provides an oxygen-rich environment for the regenerating nerve; 2) flexibility, to accommodate movement of joints and associated tendon gliding; 3) corrugation, to resist the occlusive force of surrounding soft tissue; and 4) bioabsorbability, eliminating the need for removal at a subsequent operation. This corrugated tube has an internal diameter of 2.0 mm and a length of 4 cm. Weber et al reported a prospective study on 136 nerve repairs in the hand, divided into 2 groups: group 1 consisted of standard repair with either end-to-end anastomosis or nerve graft, and group 2 consisted of nerve repair using a polyglycolic acid conduit (28). There were no statistical differences between the 2 groups overall. However, 2-point discrimination was better in the polyglycolic acid conduit group (6.8 D } 3.8 mm) than in the direct anastomosis or nerve graft group (12.9 D } 2.4 mm). The polyglycolic acid conduit provided superior results and eliminated donor-site morbidity. Reference is herein made to some embodiments of the invention utilising the implant as means of accelerating and monitoring nerve repair at nuerotube junctions or at other intevals or segments of the nuerotube . Reference is herein made to some embodiments of the invention

Neurotube is a corrugated conduit composed of polyglycolic acid with an internal diameter of 2.0 mm and a length of 4 cm. Reference is herein made to embodiments of the invention such that the implants comprise the aforementioned materials to produce a temporary implant useful for alloplastic nerve grafting and cable nerve repair.

Since the polyglycolic acid is resorbed, the problems associated with permanent tubing (i.e., Silastic, Gore-Tex), including compression and demyelination, are eliminated. The superior results achieved with this nerve grafting conduit are related to the elimination of the problems associated with a harvested nerve graft, host-donor differences in diameter, mismatches in number and pattern of fascicles and cross-sectional shape and area, and morbidity of the donor area. If there is a discrepancy in the sizes of host nerve end and tube diameter, the tube can be slit at the end to allow expansion or contraction to correlate to host nerve diameter. The artificial nerve conduit is then filled with a solution containing 1000 U of heparin per 100 mL of isotonic saline to help prevent blood clot formation, which could impede axonal regeneration.

Reference is made to the use of some embodiments of the invention wherein the implants are used to repair nerves after vein grafts and autogenous nerve .

Tendon repair Definition

Tendon repair refers to the surgical repair of damaged or torn tendons, which are cord-like structures made of strong fibrous connective tissue that connect muscles to bones. The shoulder, elbow, knee, and ankle joints are the most commonly affected by tendon injuries.

Purpose

The goal of tendon repair is to restore the normal function of joints or their surrounding tissues following a tendon laceration.Some embodiments of the present invention provide implants and methods of using thereof for tendon repair. Still other embodiments provide implants delivering in situ Cell Density Signal- 1, or CDS-I or similar products to damaged tendons.Such products act as part of a chemical switch for turning on procollagen production.

Other embodiments of the invention provide implants delivering dextrose or natural glycerin at the exact site of the injury to stimulate the immune system to repair the area. Some embodiments of the implant release the aforementioned substances in order to causes an inflammatory reaction at the exact site of injuries to such structures as ligaments, tendons, menisci, muscles, growth plates, joint capsules, and cartilage to stimulate these structures to heal. This causes fibroblasts to multiply rapidly. Fibroblasts are the cells that actually make up ligaments and tendons. The rapid production of new fibroblasts means that strong, fresh collagen tissue is formed, which is what is needed to repair injuries to ligaments or tendons.

Claims

1. A temporary surgical implant for a joint with damaged cartilage, useful for insertion into the joint space, said implant providing separation between cartilage surfaces of said joint, softened mechanical contact, reshaping of said damaged cartilage and regeneration of cartilage, said implant comprising an infilled member wherein said member comprises a. an outer envelope portion and b. an inner portion adapted to accommodate an infill said envelope characterized in that said envelope portion comprises a thermoplastic elastomer of a hardness between about 30 and about 60 Shore A, said inner portion characterized in that said inner portion comprises a thermoplastic elastomer of a hardness between about 3 Shore A and about 15 Shore A, said infill comprising pressure maintaining fluid .

2. A surgical implant according to claim 1 wherein said implant is provided with anchoring means for fixation within the joint space.

3. A surgical implant according to claim 1 wherein said implant is adapted to assume a predetermined minimum thickness under compression, said thickness under compression greater than about 1 mm and less than thickness of said implant not under compression.

4. A surgical implant according to claim 1 wherein said inner portion comprises biocompatible silicone gel

5. A surgical implant according to claim 1 wherein at least a portion of said implant comprises biocompatible materials selected from a group comprising Polylactic acid (PLA), Polyglycolic acid (PGA), Polycaprolactone (PCL) , Polydioxanone (PDO or PDS) PLGA or poly(lactic-co-glycolic acid), Polyhydroxybutyrate (PHB) and Poly-3- hydroxybutyrate (P3HB)

6. A surgical implant according to claim 1 wherein said envelope is adapted to be coated with a biomimetic coating.

7. A surgical implant according to claim 1 wherein said biomimetic coating comprises any of a group selected from EGAP Polymer and Factor H.

8. A surgical implant according to claim 1 wherein said implant is adapted to be inserted via an artheroscope.

9. A surgical implant according to claim 4 wherein said envelope is adapted to be separately implanted into said joint space, said implant further provided with an opening for post implantation introduction and withdrawal of inner portion.

10. A surgical implant according to claim 1 and 4 wherein said envelope is provided with a tap or port for pumping in and out fluids from said implant.

11. A surgical implant according to claim 1 wherein said implant further comprises at least one additional layer portion disposed between said envelope portion and said inner portion, further wherein said envelope further comprises a series of apertures for sustained release of medicines into said joint space.

12. A surgical implant according to claim 11 wherein said apertures are uni-directional valves adapted to facilitate controlled efflux of medicine and prevent influx of synovial fluid.

13. A surgical implant according claim 12 wherein said medicines are at least one selected from a group consisting of narcotics, medicaments, Cell Density Signal- 1, CDS-I ,dextrose, glycerin hormones, local anti inflammatory drugs, gold salts and salts other than gold salts.

14. A surgical implant according to claim 13 wherein said gold salts are at least one selected from a group consisting of comprise at least one selected from a group consisting of Auranofin ,Aurothioglucose, Gold thioglucose, Disodium aurothiomalate , Sodium aurothiosulfate ,GoId sodium thiosulfate, Sodium aurothiomalate, Gold sodium thiomalate Aurothioglucose and Solganal.

15. A surgical implant according to claim 1 wherein said envelope is embedded with abrasive materials useful for reshaping cartilage surfaces, said abrasive materials selected from a group consisting of diamond dust, aluminium oxide powders, salts, minerals.

16. A surgical implant according to claim 1 wherein said envelope surface is provided with a raised textured external surface, said surface comprising treads, bumps, indentations, nipples, roughenings or a combination thereof, in order to provide reshaping effects on the synovial surfaces.

17. A surgical implant as in claims 1 or 4 wherein any of said portions of infilled member comprise radio-opaque material useful for positioning said implant or monitoring status of said joint space and associated cartilaginous surfaces.

18. A surgical implant according to claim 1 wherein said infill is selected from a group consisting of solid material, nano powders or micro powders

19. A surgical implant as in claims 1 or 7 wherein said infill is a fluid.

20. A surgical implant according to claim 18, said fluid selected from a group consisting of a liquid, gas, gel, emulsion, diluted solution, heterogenous solution, aggregates or liposomes.

21. A surgical implant as in claims 1 or 4 wherein said implant comprises vertical or horizontal compartments

22. A surgical implant as in claims 1 or 4 wherein said implant is adapted for insertion into the joint space of joints of a human body said joints selected from a group consisting of knee joint, ankle joint, shoulder joint ,hip joint, palm joint , spinal facet joints, elbow joint, wrist joint and Temporal Mandibular Joint.

23. A surgical implant according to claim 1 wherein said implant is adapted for accommodating a video capsule of the GI type for monitoring the internal synovial joint environment.

24. A surgical implant according to claim 23 wherein said implant is adapted for accommodating an externally powered video camera, said implant additionally provided with a communicating tube extending from said implant outward to a subdermal location for communicating with the external power supply of said camera.

25. A surgical implant according to claim 24 wherein said tube is adapted for accommodating a fibre optic external light source for illumination of said joint space.

26. A surgical implant according to claim 24 wherein said tube is adapted for accommodating an NIRS sensor for monitoring and diagnosing processes within said joint space.

27. A surgical implant according to claim 24 wherein said tube is adapted for injecting or removing fluids, especially medicaments, powders, dyes or infill.

28. A surgical implant according to claim 24 wherein said tube is provided with a multiplicity of lumens, each lumen adapted for mediating specific functions selected from a group consisting of power supply, illumination, inner pressure control and adjustment, administration of medicaments, replenishing of medicaments, drainage of said implant, external video monitoring, administration of therapies, and withdrawal of biopsy samples.

29. A surgical implant according to claim 1 wherein said inner portion is provided with an internal NIRS sensor unit for monitoring and diagnosing processes within said joint space.

30. A surgical implant according to claim 24 wherein said NIRS sensor unit is adapted to be withdrawn from the joint space via a communicating tube and further adapted to record data concerning said joint space for subsequent study after said withdrawal.

31. A surgical implant according to claim 30 wherein a Wireless NIRS sensor unit is provided with means for wirelessly transmitting data concerning the internal joint space to an external monitor.

32. A surgical implant according to claim 1 wherein said inner portion is provided with means for providing therapeutic vibrations.

33. A surgical implant according to claim 1 wherein said inner portion is provided with heating means.

34. A surgical implant according to claim 31 wherein said heating means is a peltier device.

35. A surgical implant according to claim 1 wherein said inner inner portion is provided with cooling means.

36. A surgical implant according to claim 33 wherein said cooling means is a peltier device or a saline circulation system.

37. A surgical implant according to claim 1 wherein said inner inner portion is adapted to be inflated and deflated.

38. A surgical implant according to claim 1 wherein said envelope portion is provided with filtration means.

39. A surgical implant according to claim 1 wherein said envelope portion is provided with an opening selected from a group consisting of diagnostic window, hatch ,flap or door.

40. The surgical implant according to claim 1 wherein said implant is of dimensions such that a plurality of said implants can be stacked either vertically or horizontally in said synovial space.

41. A surgical implant according to claim 1 wherein said implant is adapted to treat inter articular fractures.

42. A surgical implant according to claim 1 wherein said intra articular fracture is selected from a group consisting of knee fracture, ankle fracture,, elbow fracture, shoulder fracture , foot fracture, wrist fracture or hand fracture.

43. A surgical implant according to claim 1 wherein said implant is adapted to treat damaged tendons

44. A surgical implant according to claim 1 wherein said implant is adapted to treat damaged nerves.

45. A surgical implant according to claim 1 wherein said implant is adapted to treat at least one from a group consisting of damaged ligaments, tendons, menisci, muscles, growth plates, joint capsules, and cartilage

46. A method for repairing and monitoring damaged cartilage in a joint space, wherein said method comprises steps of a. obtaining said temporary implant b. inserting said temporary implant into said joint space.

47. The method according to claim 46 wherein said method further includes steps of a. providing said implant with anchoring means for fixation within the joint space and fixing said implant within said joint space b. anchoring said implant .

48. The method according to claim 47 wherein said method includes steps of adapting said implant to assume a predetermined minimum thickness under compression, said thickness under compression greater than about 1 mm and less than thickness of said implant not under compression.

49. The method according to claim 46 wherein said method includes steps of providing said implant with said inner portion comprising biocompatible silicone gel

50. The method according to claim 46 wherein said method includes steps of providing said implant with at least a portion of said implant comprising biocompatible materials selected from a group comprising Polylactic acid (PLA), Polyglycolic acid (PGA), Polycaprolactone (PCL) , Polydioxanone (PDO or PDS) PLGA or poly(lactic-co-glycolic acid), Polyhydroxybutyrate (PHB) and Poly-3-hydroxybutyrate (P3HB)

51. The method according to claim 46 wherein said method includes steps of providing said implant with an envelope coated with a biomimetic coating.

52. The method according to claim 46 wherein said biomimetic coating comprises any of a group selected from EGAP Polymer and Factor H.

53. The method according to claim 46 wherein said method includes steps of inserting said implant via an artheroscope.

54. The method according to claim 46 wherein said method includes steps of a. obtaining an implant with a separate inner portion and envelope portion b. introducing said envelope portion into said joint space via said artheroscope c. inserting said inner portion into said envelope portion through said port, opening or tap of said envelope portion via said artheroscope.

55. The method according to claim 46 and claim 54 wherein said method includes steps of a. providing said envelope with a tap, port or sealable opening for pumping in and out fluids from said implant b. pumping in or out said fluids according to patient's need .

56. The method according to claim 46 wherein said method includes steps of a. providing at least one additional layer portion b. disposing said additional layer portion between said envelope portion and said inner portion, c. further providing said envelope with a series of apertures for sustained release of medicines into said joint space d. releasing said medicine into said joint space.

57. The method according to claim 56 wherein said method comprises steps of providing apertures in the form of uni-directional valves facilitating controlled efflux of medicine and preventing influx of synovial fluid.

58. The method according to claim 56 wherein said method comprises steps of selecting at least one said medicine from a group consisting of narcotics, medicaments, Cell Density Signal- 1, CDS-I ,dextrose, glycerin, hormones, local anti inflammatory drugs, gold salts and salts other than gold salts.

59. The method according to claim 58 wherein said method comprises steps of selecting at least one gold salt from a group consisting of comprise at least one selected from a group consisting of Auranofin, Aurothioglucose ,GoId thioglucose ,Disodium aurothiomalate ,Sodium aurothiosulfate ,GoId sodium thiosulfate, Sodium aurothiomalate, Gold sodium thiomalate Aurothioglucose and Solganal.

60. The method according to claim 46 wherein said method comprises steps of embedding said envelope with abrasive materials useful for reshaping cartilage surfaces, said abrasive materials selected from a group consisting of diamond dust, aluminium oxide powders, salts, minerals.

61. The method according to claim 46 wherein said method further comprises steps of providing said envelope surface with a raised textured external surface, said surface comprising treads, bumps, indentations, nipples, roughenings or a combination thereof, in order to provide reshaping effects on the synovial surfaces.

62. The method according to claims 46 or 48 wherein said method further comprises steps of infilling any of said portions of infilled member with radio-opaque material useful for positioning said implant or monitoring status of said joint space and associated cartilaginous surfaces.

63. The method according to claim 46 wherein said method further comprises infilling said member with infill from a group consisting of solid material, nano powders or micro powders

64. The method according to claim 46 or 48 wherein said infill is a fluid.

65. The method according to claim 65, wherein said method comprises steps of selecting said fluid from a group consisting of a liquid, gas, gel, emulsion, diluted solution, heterogenous solution, aggregates or liposomes.

66. The method according to claims 46 or 48 wherein said method comprises steps of a. obtaining said implant comprised of vertical or horizontal compartments b. implanting said implant into said joint space.

67. The method according to claims 46 or 48 wherein said method comprises steps of adapting said implant for insertion into the joint space of joints of a human body said joints selected from a group consisting of knee joint, ankle joint, shoulder joint ,hip joint, palm joint and spinal facet joints, elbow joint, wrist joint and Temporal Mandibular Joint.

68. The method according to claim 46 wherein said method comprises steps of a. adapting said implant for accommodating a video capsule of the GI type b. inserting said implant into said joint space c. monitoring the internal synovial joint environment.

69. The method according to claim 68 wherein said method comprises further steps of a. adapting said implant for accommodating an externally powered video camera and b. additionally providing said implant with a communicating tube extending from said implant outward to a subdermal location for communicating with the external power supply of said camera

70. The method according to claim 69 wherein said method comprises steps of a. providing said tube adapted for accommodating a fibre optic external light source for illumination of said joint space and b. activating said light source thereby illuminating said joint space.

71. The method according to claim 69 wherein said method comprises steps of a. adapting said tube for accommodating an NIRS sensor unit for monitoring and diagnosing processes within said joint space b. inserting at least part of said NIRS sensor unit into said implant via said tube c. activating said NIRS sensor unit d. monitoring interior of said joint space.

72. The method according to claim 69 wherein said method further comprises steps of adapting said tube for injecting or removing fluids, especially medicaments, powders, dyes or infill.

73. The method according to claim 69 wherein said method further comprises steps of a. providing said tube with a multiplicity of lumens and b. adapting each lumen for mediating specific functions selected from a group consisting of power supply, illumination, inner pressure control and adjustment, administration of medicaments, replenishing of medicaments, drainage of said implant, external video monitoring, administration of therapies, and withdrawal of biopsy samples.

74. The method according to claim 41 wherein said method comprises further steps of a. providing said inner portion with an internal NIRS sensor unit b. monitoring said NIRS data from within said joint space and c. diagnosing processes within said joint space.

75. The method according to claim 69 wherein said method comprises further steps of a. activating said NIRS sensor unit from within said joint space b. recording data collected by said NIRS unit concerning said joint space c. withdrawing said NIRS sensor unit from the joint space via said communicating tube d. inspecting recorded data concerning said joint space

76. The method according to claim 70 wherein said method further comprises steps of a. activating said Wireless NIRS sensor unit b. receiving wirelessly transmitted data concerning the internal joint space to an external monitor c. monitoring and inspecting said recorded data

77. The method according to claim 46 wherein said method comprises additional steps of a. providing said inner portion with means for providing therapeutic vibrations and b. activating said means.

78. The method according to claim 46 wherein said method comprises additional steps of a. providing said inner portion with heating means b. activating said heating means.

79. The method according to claim 78 wherein said method comprises additional steps of providing said inner portion with a peltier device for heating.

80. The method according to claim 46 wherein said method comprises further steps of a. providing said inner portion with cooling means b. activating said cooling means.

81. The method according to claim 80 wherein said method comprises further steps of providing said inner portion with a peltier device for cooling or a saline circulation system for cooling.

82. The method according to claim 46 wherein said method comprises further steps of a. adapting said inner portion to be inflated and deflated b. inflating or deflating said inner portion according to patient's need..

83. The method according to claim 82 wherein said method comprises steps of providing said envelope portion with filtration means.

84. The method according to claim 46 wherein said method comprises steps of providing said envelope portion with a diagnostic window.

85. The method according to claim 46 wherein said method comprises steps of a. providing said implant is of dimensions such that a plurality of said implants can be stacked either vertically or horizontally in said joint space b. stacking said implants vertically or horizontally in said joint space.

86. The method according to claim 46 wherein said implant is adapted to treat an inter articular fracture.

87. The method according to claim 46 wherein said intra articular fracture is selected from a group consisting of knee fracture, ankle fracture,, elbow fracture, shoulder fracture, foot fracture, wrist fracture or hand fracture.

88. The method according to claim 46 wherein said implant is adapted to treat damaged tendons

89. The method according to claim 46 wherein said implant is adapted to treat damaged nerves.

90. A surgical implant according to claim 46 wherein said implant is adapted to treat at least one of a group selected from damaged ligaments, tendons, menisci, muscles, growth plates, joint capsules, and cartilage