WO2006094323A2

WO2006094323A2 - Implant for protecting against fractured bones

Info

Publication number: WO2006094323A2
Application number: PCT/AT2006/000095
Authority: WO
Inventors: Gerold Holzer; Gobert Skrbenbsky
Original assignee: Gerold Holzer; Gobert Skrbenbsky
Priority date: 2005-03-08
Filing date: 2006-03-06
Publication date: 2006-09-14
Also published as: WO2006094323A3; AT501692B1; AT501692A1

Abstract

The invention relates to an implant (1) for protecting against fractured bones, especially the head of the femur, characterised by a biocompatible protective element (5) that can be arranged in the normal position between the bone (2) to be protected and the skin (4) covering said bone, and comprises at least one layer of plastic shock-absorbent material. Especially fractures related to osteoporosis can be reduced by one such internal implantable hip protection.

Description

IMPLANT TO SCHUJZ ₁ COUNTERBREAKING

The invention relates to an iraplaxitat for protection against. Broken joints, especially the thigh neck.

The risk of falling due to poor mobility and sense of balance combined with bad vision and insufficient light conditions increases with age. The risk of bone fracture is significantly increased by osteoporosis. Osteoporotic fractures are among those diseases that are one of the major causes of morbidity and associated high mortality in old age.

Osteoporosis is a disease of the skeletal system with loss or reduction of bone substance and structure, which increases with age. Throughout life, the cooking mass is in the. Equilibrium maintained by the process of regeneration of bone tissue with synchronous bone size and bone resorption. Although this reduction of bone substance caused by aging. In both sexes, women are more likely to be affected by the lack of sex hormones as a result of menopause. There are also a number of other diseases that can cause secondary osteoporosis. Options for prophylaxis include exercise and exercise as well as the absorption of calcium and vitamin D. If osteoporosis is diagnosed, additional drug therapies of various kinds are available.

Fracture at sites of predilection has been prevalent in patients with osteoporosis, but decreased bone mass is not the only cause. It is well known that older people are more likely to fall due to the slowing of agility and balance, possibly combined with poor vision in insufficient light conditions. Often the falls are so consequential that they lead to long-term hospital stays with multiple fractures and long-term fracture healing. Most of these fractures require the implantation of endoprostheses to regain adequate mobility. Negative effects in older patients, the reduction of fat and muscle tissue, because it is the natural means of damping Bumps is reduced.

For Austria, no exact figures are available for the incidence of osteoporotic fractures. In Denmark, with a population of about 5.4 million people, there are about 14,000 cases of fractures of the proximal femur per year. The surgeries and other treatments of these patients yield about 300,000 beds occupancy days, which is equivalent to about 3 to 4% of the total hospital bed days in hospitals per year in Denmark. It is expected in the future with a sharp increase in fractures of the proximal femur, not least because of increasing life expectancy.

The main cause of fractures of the proximal femur are direct falls on the hip or the greater trochanter, this is the external bone protrusion at the upper end of the femur. These fractures lead to hospitalization and bed-wear of the elderly. Patients suffering from fractures of the proximal femur usually have a reduced quality of life, as only about 20% regain full mobility. In addition, morbidity within the first year after fractures of the proximal femur is approximately 20%. Five-year survival rates are around 60%.

A large number of internal and external risk factors for falls were identified and corresponding prevention programs were developed. These have proven to be effective in reducing falls and thus reducing fractures and are therefore also cost-efficient.

Hip energy absorption probably plays a greater role in the occurrence of fractures of the proximal femur than the maximum force of the bone itself, which deteriorates with increasing age. The soft tissues surrounding the hip affect energy absorption in the event of a fall. This fact is reflected in the lower fracture risk for thicker patients. A protection system must therefore serve primarily to transfer the energy from the proximal femur to the surrounding soft tissues, but at the same time also to absorb energy. One way to reduce the risk of fractures of the proximal femur are hip protectors, which are worn in a corresponding device usually in the form of a pair of pants on the hip. Under in vitro conditions, depending on the systems used so far, it is possible to neutralize about 20 to 95% of the forces acting on the bone during a fall and to reduce the energy incident below the threshold value necessary for the formation of a fracture. The results of clinical studies show that hip protectors are effective in fracture prevention, especially by institutionalized patients. In this case, a reduction in the fractures of the proximal femur by residents of nursing homes by 50% can be observed. However, the compliance to wear hip protectors is rather low.

Currently available systems for protecting against fractures in the area of the proximal femur are, as mentioned above, to be applied externally over the hip. For example, US 2004/0049827 A1 describes a hip protector integrated in a pants-like garment. However, many patients do not put on the external hip protectors during the night hours for comfort, which increases the risk of a fall-related fracture, especially during the night, for example when going to the toilet. The reasons most commonly cited in studies for not wearing hip protectors are limitation of range of motion due to tight fit, extra effort and time spent on donning, urinary incontinence, and other physical difficulties or diseases. In addition, an incorrect position of the hip protector results in insufficient cushioning and energy absorption in the event of a fall and thus inadequate protection against fracture.

The hip protector according to US 6 334 443 Bl attempts to remedy this problem by adhering the protective element to the skin. However, adhesives on the skin usually lead to skin irritations, which in turn can lead to a lack of readiness to wear the protectors. In addition, the sticking of the hip protector also requires a certain amount of - A - chic, which is often not given in the elderly.

In addition to the aforementioned hip protectors, there are also implants that protect osteoporotic bone segments against fractures. For example, EP 1 044 276 B1 describes such an implant, which is used in particular in the femoral neck, the spine or the wrist and thus represents an amplification of the bone mass weakened by the osteoporosis. The incorporation of such implants usually requires a relatively complex operation, which is a high risk for the patient, especially older age. In addition, usually a time- and cost-intensive rehabilitation is required, which reduces the acceptance of such prophylactic implantations.

The object of the present invention is therefore to provide an implant for protection against bone fractures, in particular of the femoral neck, which is particularly quick and easy to use, and which is as simple and inexpensive as possible and represents an effective protection of the bone against fracture. Disadvantages of known protective devices should be avoided or reduced.

The object of the invention is achieved by a named implant, which consists of a biocompatible protective element which can be arranged in the position of use between the bone to be protected and the overlying skin, with at least one layer of shock-absorbing plastic material. The invention relates to a simple implantable aid for the protection of bony lesions, in particular fractures in the region of the proximal femur. The implant effectively protects patients with multiple risk factors for fractures, especially the proximal femur. Surgery for implantation can be performed under local anesthesia and does not require time- and cost-intensive rehabilitation. The biocompatible protective element is simply inserted between the bone to be protected and the overlying skin, surgically fixed and provides optimal protection against breakage of the underlying bone by the at least one layer of shock-absorbing plastic material. By the O Impact-absorbing plastic material, the forces that occur in a fall are absorbed and converted, for example, into heat. In addition to the biocompatibility of the protective element and a hypoallergenic property is appropriate, so that no foreign body reactions can occur.

In this case, the protective element itself may consist of biocompatible material or be surrounded by a covering of biocompatible material.

According to a further feature of the invention, it is provided that the protective element of the implant contains at least two layers arranged one above the other in the direction of a force acting on the bone to be protected. Preferably, the layers consist of different materials, whereby an optimal distribution and absorption of the forces occurring during a fall can take place.

At least two layers may have a three-dimensional structure at their contact surfaces. Such a design of the transition from one layer to the other of the protective element can also optimally address the deflection of the forces, and thus an effective protection of the underlying bone can be achieved.

In this case, the said three-dimensional structures may be formed in cross-section, for example, wave or jagged.

In order to achieve a distribution of the mostly punctiform forces acting on the entire protective element of the implant, at least one layer of energy distributing plastic material may be made. Such a layer, which may be formed for example of plastic fabric, serves to distribute the energy and not for absorption. Advantageously, the energy distributing plastic layer is arranged on the outside of the implant.

In order to achieve a higher acceptance of the implant, it is advantageous if the protective element on the in the use position on the body to be protected has a maximum thickness of less than or equal to 15 mm. By choosing a suitable material, such as an elastomer, optimal energy absorption and thus effective protection of the bone can be achieved even at low material thicknesses.

Advantageously, the protective element is convexly shaped in the direction of the acting force. This form takes on the anatomical conditions, in particular in the protection of the femoral neck, consideration.

In the direction of the bone to be protected, the protective element may be concave.

In order to allow easy fixation of the implant at the desired location, the protective element may have puncture areas of reduced thickness for suture fixation. At these piercing regions, which are preferably arranged on the edges of the protective element, the surgeon can easily pierce the needle connected to the surgical thread and fix the implant to the corresponding tissue or the like.

Alternatively or additionally, the protective element can also have holes for seam fixation.

In order not to cause too great restriction of the mobility by the implanted protective element, this may consist of at least two mutually movable parts. This means that the implant essentially has a joint that participates to a certain extent in the movement of the limb or the like to be protected.

This joint can be formed in that the parts of the protective element are movably connected to one another via a common sliding surface. For example, a certain mobility of the parts of the protective element can be achieved by an obliquely arranged sliding surface. To keep the parts in the desired position to each other, they may for example be surrounded by a sheath. Depending on the application, the protective element may, for example, have substantially round or elliptical but also elongated basic shape.

In order to be able to control the position of the implant, marking elements are provided according to a further feature of the invention, which can be formed for example by metal wires. Thus, for example, after a fall of the patient via an X-ray, the integrity and the position of the implant can be checked and, if necessary, the indication for a change of the implant can be made.

The present invention also relates to a method for implanting the described implant. In this case, the implant is used in the case of protection of the proximal femur on the lateral side of the thigh. Through a small surgical procedure, which can usually be done under local anesthesia, the protective element is introduced via a small incision between the femur and the skin and either fixed directly to the femur under the muscles or over the muscles or subcutaneous fat. The fixation can be done either directly on the periosteum, in the area of the bursa trochanterica, the fascia lata or other structures suitable for fixation.

The present invention will be explained in more detail with reference to the accompanying drawings, which show embodiments of the implant.

1 shows schematically the section through a patient in the region of the hip with a correspondingly arranged implant; FIG. 2 is a plan view of an embodiment of an implant; FIG. Fig. 3 is a sectional view taken along section line III-III of Fig. 2; 4 shows a sectional view through another embodiment of an implant; 5 shows a sectional view through a further embodiment of an implant; 6 shows the plan view of a further embodiment of an implant; 7 shows a sectional view through the implant according to FIG. 6 along the section line VII - VII; Fig. 8 is a sectional view through a part a further embodiment of an implant; and FIG. 9 shows the plan view of a further embodiment of an implant.

1 shows the arrangement of an implant 1 according to the invention for the protection of the femur 2 or of the greater trochanter 3, in particular in patients suffering from osteoporosis. For this purpose, the implant 1 is inserted between the bone 2 to be protected and the skin 4 of the patient. In the event of a fall, the force F acting on the bones 2 and 3, respectively, is distributed and absorbed by the implant 1, thereby reducing the force effectively acting on the bone 2 to a value which is below the threshold for producing a bone Fracture lies. Thus, effective protection of the corresponding bone 2 takes place. Although the present description focuses on the protection of the femur, the present implant 1 can also be used to protect other bones. The implant 1 is intended for the primary prevention of fractures, especially in the area of the proximal femur, when, for example, due to the existence of multiple risk factors and a low bone density, the risk of fractures is particularly increased. On the other hand, the implant 1 can also serve for the secondary prevention of fractures by prophylactically inserting the implant 1 after fractures have already occurred at sites of predilection of other bones or the contralateral femur. An essential advantage of the protective system described is the immediate onset of action and that a cooperation of the patient after implantation is no longer necessary. Also, a slipping of the protector, as it may occur in external hip protectors, not done.

FIG. 2 shows a plan view of an embodiment of the implant 1 whose protective element 5 has an essentially oval basic shape. At four points along the outer periphery of the protective element 5 are areas 6 with holes 7, which serve for seam fixation. Instead of holes 7, the regions 6 can also have reduced material thicknesses, through which the surgical suture can be set.

The sectional view according to FIG. 3 shows a preferred embodiment. shape of the implant 1, which is convex in the direction of the applied force F and concave in the direction of the bone 2 to be protected. The thickness D of the protective element 5 of the implant 1 should preferably be a maximum of 15 mm.

4 shows a further embodiment of the subject implant 1, in which the protective element 5 is surrounded by a covering 8 made of biocompatible material. Often, the shock-absorbing plastic material of the protective element 5 is not biocompatible due to additives contained therein, such as plasticizers or the like, so that the biocompatibility must be produced by a corresponding sheath 8.

The implant 1 according to FIG. 5 consists of a protective element 5 which has two superimposed layers 9, 10 made of impact-absorbing plastic material. By suitable choice of material optimum distributions of the forces can be achieved. In addition, the two layers 9, 10 at their contact surfaces 11 have a three-dimensional structure, which may be formed, for example, in cross-section wave or jagged. This also allows a corresponding introduction of the forces can be achieved in the underlying shock-absorbing layer. In addition, a layer 12 of energy-distributing plastic material can be arranged above the impact-absorbing layers 9, 10.

6 shows a plan view of a further embodiment of an implant 1 consisting of two parts 13, 14 which are movable relative to each other. As can be better seen in the sectional view according to FIG. 7, this movable connection of the parts 13, 14 of the implant 1 can be formed by connecting the parts 13, 14 to one another via a common inclined sliding surface 15. In order to prevent the parts 13, 14 from slipping apart, an envelope 8 can be arranged around the parts 13, 14. By this movable embodiment of the implant 1, a possible restriction of movement of the patient is reduced.

8 shows a sectional view through a part of a further embodiment of an implant 1, in which two layers 16 made of shock absorbing material with two layers 17 with energy distributing material are arranged alternately one above the other.

9 shows a top view of a further embodiment of an implant 1, in which the protective element 5 has marking elements 18, preferably in the form of metal wires, by means of which the position of the implant 1 in the body can be ascertained with the aid of an X-ray. Also, by appropriate arrangement of such marking elements 18, the deformation of an implant 1 can be assessed after a fall of the patient and then a reimplantation of a new implant 1 can be decided.

The present invention provides an effective way to protect against particular osteoporotic fractures, especially of the femoral neck.

Claims

Claims:

1. implant (1) for protection against bone fractures, in particular of the femoral neck, characterized by a in the position of use between the bone to be protected (2) and the overlying skin (4) can be arranged biocompatible protective element

(5) with at least one layer of impact-absorbing plastic material.

2. Implant (1) according to claim 1, characterized in that the protective element (5) itself consists of biocompatible material.

3. implant (1) according to claim 1, characterized in that the protective element (5) with a sheath (8) is surrounded by biocompatible material.

4. implant (1) according to one of claims 1 to 3, characterized in that the protective element (5) at least two in the direction of a force acting on the bone (2) force (F) superimposed layers (9, 10) ,

5. implant (1) according to claim 4, characterized in that at least two layers (9, 10) at their contact surfaces (11) have a three-dimensional structure.

6. implant (1) according to claim 5, characterized in that the structure is formed in the cross-section wave or jagged.

7. implant (1) according to one of claims 4 to 7, characterized in that at least one layer (12) consists of energiewerteilendem plastic material.

8. implant (1) according to one of claims 1 to 7, characterized in that the protective element (5) arranged on the in the position of use on the bone to be protected (2) has a maximum thickness (D) less than or equal to 15 mm ,

9. implant (1) according to one of claims 1 to 8, characterized in that the protective element (5) in the direction of the applied force (F) is convex.

10. implant (1) according to one of claims 1 to 9, characterized in that the protective element (5) in the direction of the bone to be protected (2) is concave.

11. implant (1) according to one of claims 1 to 10, characterized in that the protective element (5) has puncture areas with reduced thickness (d) for suture fixation.

12. Implant (1) according to one of claims 1 to 11, characterized in that the protective element (5) has holes (7) for seam fixation.

13. implant (1) according to one of claims 1 to 12, characterized in that the protective element (5) consists of at least two mutually movable parts (13, 14).

14. Implant (1) according to one of claims 1 to 13, characterized in that the parts (13, 14) of the protective element (5) via a common sliding surface (15) are movably connected to each other.

15. Implant (1) according to one of claims 1 to 14, characterized in that the protective element (5) has a substantially round or elliptical basic shape.

16. implant (1) according to one of claims 1 to 15, characterized in that marking elements (18) are provided.

17. Implant (1) according to claim 16, characterized in that the marking elements (18) are formed by metal wires.