CN101730509B

CN101730509B - Fixation device

Info

Publication number: CN101730509B
Application number: CN200880021119XA
Authority: CN
Inventors: H·蒙特斯德奥卡巴尔德拉斯; M·布朗; A·汤普森; G·豪林
Original assignee: Smith and Nephew PLC
Current assignee: Smith and Nephew PLC
Priority date: 2007-04-19
Filing date: 2008-04-15
Publication date: 2013-01-02
Anticipated expiration: 2028-04-15
Also published as: AU2008240414B2; CA2686117C; CN101730509A; CA2686117A1; AU2008240414A1; JP2010524541A; WO2008129241A1; EP2148624A1; JP5562831B2

Abstract

The present invention relates to a fixation device and in particular to a device which aids anchoring of orthopaedic fasteners and implants to bone. The invention also relates to a fixation apparatus and a method of fixation.

Description

Fixture

Technical field

The present invention relates to a kind of fixture, and relate more specifically to a kind of helping orthopedic securing member and prothesis implant body are anchored to device on the bone.The invention still further relates to a kind of fixing device and fixing means.

Background technology

Term " is fixed " and is typically referred in operation technique location such as prothesis implant body and orthopedic securing member such as screw, pin, plate, binding agents and anchor on the callus (for instance, for example bone).Yet it not is always to have provided enough anchorings that this class implant and/or securing member are positioned, and is unsuitable and harmful in some cases.For example, when the fracture of operation technique treatment and reparation patients with osteoporosis, this problem is obvious especially.Osteoporosis is a kind of osteopathia, and therefore bone mineral density reduces, so that bone becomes more crisp.Therefore, the easier fracture of osteoporotic bone, and more be difficult to treat with trauma surgery and reconstruction operations at clinicing aspect.

The surgical repair fracture is usually directed to plate is placed on the fracture, so that plate bridge joint fractures, and use pin or screw that plate is anchored on the bone.Bone is located, again aimed at and support to plate with the combination of screw around fractures, to help healing.

Yet especially in osteoporotic bone, screw is fixed common poor effect, because screw is not securely fixed on the bone.Generally speaking, can be fixed on the bone in order to make conventional screw, it must be screwed in the perforate that size is slightly little in the bone.Yet this just makes bone be subject to very large power, in some cases this power bone that can damage or fracture.In addition, plate being held in place required power is born by screw certainly.This power is directly delivered on the zone of the bone that is in direct contact with it.Be delivered at additional load in the situation of plate, for example when patient moving, this additional load also is distributed between the screw.Ostealleosis around these power and load are tending towards making, and therefore screw is fluffed.In order to alleviate this problem, can use the more screw of number, make to load on to distribute on the more contact point of number and spread.Also can use additional plate, binding agent and filler.Yet such solution is not always desirable, especially need to remove in follow-up phase in the situation of plate and screw, perhaps in the situation of suffering from osteoporosis the patient as indicated above.

Another problem relevant with this type of surgical repair is, need to make bone be ready to accommodate screw or the pin of given shape.To this, the perforate degree of depth and the screw length that drill through in bone must be in the accurate tolerance.If the perforate of preparing is shorter than screw, then screw will can not laid suitably, and plate can not be fixed on the bone fully.In addition, for the abundant anchoring to pin is provided, pin must insert enough degree of depth in the bone.Yet, inserting in the situation too dark in the bone at pin, bone may break and lose all around screw thread and fix.In this case, just need to insert larger screw, perhaps may insert screw in new position.It is comparatively general in the bone during this type of operative procedure breaks the patient who is especially suffering from osteoporosis.

Summary of the invention

During one object of the present invention is to address the above problem some or all, and a kind of device is provided, it is allowed to improve to be fixed in the relatively poor bone of quality and reduces simultaneously the load of directly being born by bone.

Therefore, according to a first aspect of the invention, provide a kind of stopper, it expands in the time of can be in inserting bone cavity, and is suitable for accommodating securing member or implant, thereby securing member or implant are anchored on the bone securely.

Preferably, stopper be designed to before being inserted into bone cavity, make this stopper to be positioned on securing member or the implant or among, to strengthen fixing to securing member or implant.

Therefore, according to a second aspect of the invention, provide a kind of fixing device that comprises securing member or stopper.

Generally speaking, securing member adopts the form of screw or pin, and stopper then comprises be used to the path of accommodating screw or passage.Therefore securing member is fixed on the stopper, but not directly is fixed on the bone.Therefore therefore, the power of being born by securing member is delivered on the stopper, and with stopper but not bone self shared.

Stopper is preferably and comprises the material that can change shape when being subject to encouraging.It is desirable to, stopper comprises shape-memory polymer (SMP) material, but also can comprise marmem, for instance, and for example Nitinol, the perhaps combination of marmem and SMP.

Shape-memory polymer (SMP) is the material that can " remember " " forever " macroshape, it is directed or be manipulated to the shape of temporary transient or dormancy (dormant) under uniform temperature and/or stress, and is relaxed to subsequently stressless state or shape original or that remember.Lax usually promote by heat application, electric energy or environmental energy or encourage, SMP is handled or orientation.This lax relevant with the elastic deformation energy of the directed storage of SMP in SMP.The degree of orientation of SMP is to cause lax driving force.Therefore, directed degree is larger, and the power or the energy that then are stored among the SMP are just larger, and therefore when being triggered by extra power or promoting, then drive the lax power of SMP or energy just larger.

As other polymer, SMP can be classified into two main kinds; They can be unbodied, thereby lack the sequence of positions of any rule at molecular level, and perhaps they can be semi-definite form, and it comprises crystalline region orderly on the molecular level and amorphous region in same sample.

The plastic deformation of amorphous SMP and SMP composite causes forming directed amorphous or semi-crystalline polymer network structure.The orientation of SMP and SMP composite can by stretch, traction, or compression stress and/or shearing force be applied on the SMP realize.SMP can be by applying any in these power or it makes up to carry out orientation, and can carry out under the temperature of ambient temperature or rising.Generally speaking, before applying orientation force or a plurality of orientation force, the temperature of SMP is elevated near the glass transition temperature (Tg) that is higher than ambient temperature and reaches SMP.The temperature of SMP of raising in this way helps to prevent that SMP from breaking when orientation force just is applied thereto.Glass transition temperature is a such temperature, namely be lower than at that time, then the physical property of amorphous SMP shows as the mode that is similar to solid, and is being higher than at that time, then they show as more as rubber or liquid, allow that SMP carries out plastic deformation and do not have the risk of fracture.After SMP orientation, reduce temperature, and SMP fixes with the structure of temporary transient or dormancy.

The network structure of orientation is stable physically far below glass transition temperature (Tg) time, and molecular mobility wherein is very low.Yet when being close to or higher than the glass transition temperature of polymer, molecular motion just strengthens fast, and causes that directed network structure is lax, usually also is attended by the physical change of SMP size.Between relaxation period, directed SMP is tending towards returning to original size of unoriented SMP, the shape of gaining the name thus " memory " material.Yet, return to original shape and depend primarily on degree of crystallinity, orientation, micron order and nanoscale structures, and directed cancellated relaxed state.For copolymer, other key factor is their detailed composition and their concrete thermal characteristics, the i.e. glass transition temperature of their component or melt temperature.

What believe is that relaxation almost occurs with constant volume.For the SMP of hemicrystalline orientation, the recovery extent between relaxation period depends on its degree of crystallinity and structure, and is difficult to return to fully its original shape.On the contrary, the SMP of unbodied orientation, copolymer and their composite can roughly be got back to its original shape under the relaxed state that is fit to.

Degree of orientation is to cause lax driving force.Degree of orientation is larger, and the power or a plurality of power that namely are applied to SMP are larger, and then driving force is just larger.

Between relaxation period, directed SMP discharges stored internal force or energy.For example, by along its longitudinal axis single shaft apply the directed cylindrical SMP of stretching force will be under the free boundary state, between relaxation period, shrink and expand at diameter in length, this free boundary state is the situation that does not apply physical constraint.Therefore, when cylindrical SMP is lax, it will cause the contractility along its longitudinal axis, and also cause the expansionary force that the footpath makes progress.Degree of orientation and the quality of the polymer of these longitudinal forces and radial force and orientation are proportional.Degree of orientation is larger, and is namely larger in the power that is applied to during the orientation on the SMP, and the quality of SMP is larger, and then these longitudinal relaxation power and radial relaxation power are just larger.For the SMP of other geometry, relaxation force also will depend on degree or the size of orientation force, the direction of the orientation force that applies, and the quality of directed SMP.The relaxation rate of SMP or shape regeneration rate depend on geometry, the treatment conditions of sample, and the more important thing is quality and the thermal diffusivity that depends on SMP.

The glass transition temperature of SMP will change based on many factors, such as molecular weight, composition, the structure of polymer, and other factors known to ordinary skill in the art, but usually large between 35 ℃ to 150 ℃ scope.

Preferably, the stopper that comprises SMP is carried out prestress or orientation.Yet, will be appreciated that, can any moment before use or insertion bone carry out prestress or orientation to stopper.

Stopper and path advantageously are cylindrical, and path is preferably and is positioned at the center and along the longitudinal axis of stopper.Stopper cylindrical is preferred, because it is assembled to also easily as in the columniform bone drilling substantially.Path is positioned at the stopper center to be diffused on stopper and the whole stopper with allowing the stress equilibrium that is loaded on the screw.

Cylindrical plug carries out orientation by stretching this stopper along its longitudinal axis usually.Carrying out in this way orientation makes the stopper prolongation and its diameter is reduced.Preferably, stopper is carried out orientation, until its diameter is less than the opening diameter of preparing in bone, stopper will be arranged in this perforate.Like this, stopper can utilize very little power or firmly not insert in the bone.This at bone very crisp thereby power can cause fracturing or or even the bone situation of breaking under particular importance.

Preferably, stopper is also by making diametrically path stretch around this path directed.This for example can realize greater than the elongated member of the diameter of the path of this formation by forming the diameter have less than the path of the diameter that is inserted into securing member wherein and promoting diameter via formed path, for instance, this elongated member for example is pin.Pushing pin makes this path stretch diametrically in this way.

Preferably, the securing member elongate bars section that has head and extend from described head.Preferably, the diameter of head is less than or equal to the diameter of lax stopper.Like this, overlapping with regard to not existing between securing member and bone.Therefore, be delivered to any load on the securing member and just can't help bone and bear, but be delivered on the stopper, and directly and the stopper shared.

In use, and after the stopper of orientation had inserted in the bone cavity of preparing, stopper relaxed by the heat that is passed on it usually.The lax of stopper causes that it radially expands towards the chamber wall, until it is full of this chamber fully.The active force of lax stopper is anchored at stopper wherein securely against the chamber wall.The material of stopper also is full of any irregular place of chamber wall when lax, this further is used for stopper is anchored in this chamber.

The lax of stopper also impels channel wall radially to shrink towards securing member.Comprise that in the stopper orientation in the situation of circumferentially extending, the radial contraction of path is comparatively remarkable.The active force of lax stopper provides close-fitting clamping around securing member against securing member, and this can improve the anchoring of securing member in stopper significantly.Be in the situation of screw at securing member, for example, the channel wall of lax stopper meets screw thread form, provides along the effect of the further anchoring of fastener threads.

Preferably, securing member is metal fastenings.Advantageously, heat can be via the securing member transmission, so that stopper is lax.For example, heated probe can be applied to the head of metal fastenings, its with heat along the conduction of the length of securing member, and therefore with heat more Transmit evenly to stopper.Advantageously, stopper can comprise the heat conduction particle such as metallic particles, so that heat more evenly and quickly is distributed on the whole stopper.Securing member also can comprise the pipeline (channel) that extends along its length, and it ends at the opening at head place.This will allow that heating element heater or probe directly insert in the screw and insert along this pipeline, thereby improve the heat transmission from the screw to the stopper.

As alternative, screw can be nonmetallic materials, for example PEEK or PE.Screw also can be the SMP material, and it can be identical or different with the SMP material of stopper.Preferably, the SMP material of stopper and securing member is different.Like this, stopper will be lax with different speed with securing member, and this can increase in the securing member that expands and the friction stree between the stopper, thereby improves the anchoring effect of securing member in the stopper path.

Preferably, fixing device comprises more than one stopper and securing member.Preferably, fixing device comprises support unit, and it is used for being placed on the fracture so that this support unit bridge joint fractures.Preferably, support unit is plate.Plate can be general planar, or is configured to accommodate the shape of the attached bone thereon of this plate.Plate can comprise maybe can have the perforate that is formed at before use suitable number wherein be used to the perforate of accommodating securing member.In use, use a plurality of securing members and stopper that plate is anchored on the bone.The combination of plate, securing member and stopper provides a kind of and has located, again aimed at and support bone in order to help the mode of healing around fractures.

Therefore, according to a third aspect of the invention we, provide a kind of bone fixing means for repair of fractures, it comprises the steps:

The adjacent bone folding part forms the chamber in bone;

Fixing device is navigated to fractured area; And

Stopper is expanded at intracavity, thereby fixing device is anchored on the bone.

Generally speaking, the chamber adopts the routine operation drilling tool to form, and has the general cylindrical shape of reflection conventional bit shape.Yet this chamber can have any suitable shape; Simultaneously stopper can expand, though to be full of this chamber its shape.For example, this chamber can have square, ellipse or hexagonal cross-section; The non-circular character in this chamber prevents that also stopper from rotatablely moving, and therefore prevents from sliding at intracavity.

Preferably, the surface of chamber wall is non-smooth, allows that the SMP stopper is lax and expand into irregular place in the wall of chamber, so that stopper further firmly grasps therein, thereby further improves the anchoring of stopper in the chamber.As alternative, this chamber can form and comprise one or more grooves in the wall of chamber.As alternative, or in addition, the profile in this chamber can form allows that the SMP stopper is lax to be full of this profile.

The fixing device location is generally included the step in formed each chamber of stopper insertion of orientation.Plate is placed on the fractures, so that be used for accommodating the perforate of securing member and the via alignment of each stopper in the plate.Each securing member all inserts via the perforate in the plate, and is inserted in the path of stopper, thereby plate is fixed on the stopper.Be in the situation of screw at securing member, for example, it more effectively is incorporated in the path of stopper by screwing action.Then the SMP stopper relaxes by the molecular motion of excitation SMP, thereby causes the expanded radially of stopper.The expanded radially of stopper is wedged intracavity with stopper, therefore with the stopper anchoring, and therefore fixing device is anchored on the fracture more securely.The SMP stopper is lax also to make the path of stopper radially shrink, so that it more closely is fixed in securing member wherein, thereby further fixing device is fixed on the bone.

Preferably, the excitation molecular motion realizes by energy is applied to the SMP stopper from external source.Preferably, the energy that applies adopts the form of heat.For example, the heat that comes from heated probe can be applied directly on the securing member, this securing member then again via with along the length of stopper Transmit evenly heat more, thereby provide stopper to expand more uniformly at intracavity.Preferably, SMP is heated above the glass transition temperature (Tg) of SMP.This temperature depends on the type of used SMP, but normally in 45 ℃ to 135 ℃ scope.

As alternative or in addition, by utilizing multi-form energy, for example magnetic field, electric current, ultrasound wave, electromagnetic radiation such as microwave, visible light and infrared light, or any one combination of the energy of these forms can promote or trigger expansion step.

The molecular motion of excitation SMP also can realize by making directed SMP be exposed to plasticizer.Make SMP be exposed to the Tg that plasticizer can reduce SMP, thereby increase its molecular mobility.Like this, the molecular mobility of directed SMP can increase to is enough to cause that directed network structure is lax.Be exposed to plasticizer at the SMP of orientation and be not sufficient to make in the lax situation of SMP, for example, for the energy of form of heat also can be applied on the SMP.Like this, directed SMP can be lower than make with heat separately under the temperature required in the lax situation of SMP lax.Therefore, SMP can formalize under lower temperature, thereby allows thermo-sensitive material is added on the SMP.Thermo-sensitive material for example can comprise releasable bioactivator such as glycerol only son acid esters, bone marrow aspirate, the angiogenesis factor that will help fracture repair and osteogenic factor.

Plasticizer can be biocompatible volatile liquid or gas form.The example of this type of gaseous state plasticizer can include but not limited to oxygen and carbon dioxide.The example of this type of liquid plasticizer comprises but also is not limited to water and aqueous solution of inorganic matter such as sodium chloride solution.

Preferably, SMP is biocompatible, and can be and can absorb or can not be resorbent again, or both combinations.The example of the SMP that is fit to comprises but also is not limited to polyether-ether-ketone (PEEK), polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA), polyacrylate, poly-alpha-hydroxy acid, polycaprolactone, polydioxanone, polyester, polyglycolic acid, Polyethylene Glycol, polyactide, poe, Quadrafos, polyoxaester, poly phosphate, polyphosphonates, polysaccharide, polytyrosine carbonate, polyurethane, with and copolymer or blend polymer.

Preferably, the SMP of SMP for strengthening.Preferably, the SMP of enhancing comprises composite or the matrix that contains reinforcing material or wild phase such as fiber, rhabodoid, tablet and filler.More preferably, polymeric material can comprise glass fibre, carbon fiber, polymer fiber, ceramic fibre or ceramic particle.

Preferably, stopper is coated with osteogenic materials, for instance, for example is hydroxyapatite or calcium phosphate.

Preferably, stopper and/or securing member and/or support unit be porous or half porous.The porous of fixing device is infiltrated permissive cell wherein from surrounding tissue, and it is integrated thereby integrate to strengthen by for example bone.

Preferably, one or more activating agents are incorporated in stopper and/or securing member and/or the support unit.The activating agent that is fit to comprise but also be not limited to osteoporosis agent, Diphosphonate, osteogenin matter, antibiotic, antibiotic medicine, angiogenesis factor, osteogenic factor, somatomedin, glycerol only son acid esters, nethike embrane extract, thrombin, modified protein, be rich in platelet blood plasma/solution, blood plasma/solution, bone marrow aspirate that platelet lacks, and plant-derived group or faunistic any cell, such as cell, the rest cell of living cells, preservation, and dead cell.

Preferably, activating agent is incorporated in the stopper, and discharges during SMP relaxes or softens (degradation).Advantageously, incorporating activating agent into also can be used to infect and/or promote neoblastic growth in implant site place opposing.

Preferably, the outer surface of SMP stopper is coated with binding agent or interface reinforcing agent.Preferably, when the SMP stopper was lax, binding agent melted at least in part.When the SMP stopper was lax, the binding agent of fusing was forced to against bone on every side by the active force of lax stopper, and entered in some cases in this bone on every side.Binding agent can be adhesive for example, or is included in the material that melts under the lax required temperature of directed SMP stopper.Preferably, binding agent is polycaprolactone (PCL).

Preferably, binding agent comprises the biological activity element, and when the SMP stopper was lax, this biological activity element can discharge.Binding agent also can comprise the mechanical adjustment element, and it changes physical property or the mechanical performance of SMP stopper, for example, and the softening rate of SMP stopper or flow behavior.As alternative, stopper can comprise outside adjusting cover or coating, and it comprises biological activity element and/or mechanical adjustment element.

Generally speaking, under same temperature, outside viscosity of regulating cover or coating is compared less with the SMP stopper.Outside adjusting cover or coating can cover the whole outer surface of SMP stopper, or only cover its part.For example, the outside cover of regulating can be strips.Outside regulate cover or coating is soluble, and can comprise and to absorb again and/or can not resorbent polymer.

Preferably, outside adjusting cover or coating are hydrophilic, and when being exposed to aqueous fluid, it expands to form gel, and this gel can delivery of biologically active element and/or mechanical adjustment element.

Description of drawings

Now with reference to accompanying drawing, embodiments of the invention are only described by way of example, in the accompanying drawings:

Figure 1A is the side cross-sectional view according to fixing device of the present invention, and this fixing device comprises the directed stopper of the securing member that contains screw-type, shows it and inserts in the bone cavity, and this bone cavity obviously has the diameter larger than the stopper of orientation;

Figure 1B is the view that is similar to Figure 1A, shows the fixing device that is fixed in the bone cavity, and the arrow that is labeled as E clearly show that the SMP stopper is towards the expanded radially of chamber wall after the triggering stopper is lax;

Fig. 2 A is perspective view and starts from the side that has the oriented cylindrical plug of central cylindrical path according to of the present invention;

Fig. 2 B is the similar view of the stopper of the orientation among Fig. 2 A in the insertion bone cavity, clearly show that the diameter of directed stopper less than the diameter in this chamber, in order to stopper is inserted wherein;

Fig. 2 C is the view that is similar to Fig. 2 B, clearly show that the stopper of wedging after stopper is lax in the chamber, and the arrow that is labeled as E clearly show that stopper is towards the expanded radially of chamber wall;

Fig. 2 D is the view that is similar to Fig. 2 C, shows in the path of securing member insertion stopper;

Fig. 3 A to Fig. 3 E is according to the various structures of stopper of the present invention and the plane graph of shape, shows the path at the center of being positioned at;

Fig. 4 A to Fig. 4 E is similar to the various structures of Fig. 3 A to Fig. 3 E and the plane graph of shape, here not shown path also;

Fig. 5 A to Fig. 5 D shows according to stopper insertion of the present invention and is expanded to have in the difform chamber, comprises and sees in the plane similar hexagon, ellipse and foursquare chamber;

The side view of Fig. 6 A to Fig. 6 C for partly illustrating, (partly) show according in the fixing device insertion bone cavity of the present invention, the chamber wall has groove, directed stopper is lax to groove when its excited target, thereby the anchoring of the improvement of stopper in this chamber is provided, and the arrow that is labeled as E clearly show that stopper is towards the expanded radially of chamber wall;

Fig. 7 A to Fig. 7 C is the side view that is similar to Fig. 6 A to Fig. 6 C, shows the not isostructure of the groove in the wall of chamber;

Fig. 8 a to Fig. 8 d shows the fixed sleeve part of stopper, securing member and plate that comprises according to the present invention and is assembled on the fracture;

Fig. 9 is the plane graph of Fig. 8 B;

Figure 10 is for partly illustrating the view of Fig. 8 C with the form of plane graph;

Figure 11 a to Figure 11 d has the heteroid side cross-sectional view that the bone cavity of profile is arranged;

Figure 12 a to Figure 12 d is the diagram of the bone cavity that profile is arranged of Figure 11 a to Figure 11 d, and is shown here to have the lax stopper that comprises securing member;

Figure 13 is the diagram of SMP stopper with orientation of polycaprolactone (PLC) layer that is coated on its outside curved surface, and the SMP stopper is shown the dip stick that has the size pointed out in background here;

Figure 14 a is the side cross-sectional view by the stopper that relaxes among Figure 13 of observation by light microscope in bone cavity; And

Figure 14 b for by observation by light microscope to Figure 13 in the side cross-sectional view of lax stopper in bone cavity that does not have polycaprolactone (PLC) layer.

The specific embodiment

Referring to accompanying drawing and at first referring to Fig. 2 a, shown is substantially by the SMP stopper of the columniform orientation of reference number 2 expressions, and it has outer wall 4 and passage 6, and passage 6 extends at stopper 2 centers and along its longitudinal axis.Passage 6 ends at front end 8 places of stopper 2 in being suitable for accommodating the opening 10 of metallic screw 12.The length of the length of passage 6 and screw 12 axles adapts.

In this embodiment, stopper 2 is by making it stretch directed along its longitudinal axis.This causes stopper 2 elongated, and its diameter narrows down.

Fig. 2 B to Fig. 2 D shows (not shown) in the chamber of preparing 14 that only single stopper 2 is arranged to adjacent bone folding part in the bone 16.Yet what recognize is that a plurality of stoppers 2 that hold fractures can adopt similar mode to settle.In this embodiment, as shown in Fig. 2 B, stopper 2 inserts in the chamber 14, and then relaxes as shown in Fig. 2 C.The lax of stopper 2 encouraged by it is applied heat, in this embodiment, applies heat with the heated probe (not shown).Stopper 2 is lax to be impelled stopper 2 14 walls radially expands towards the chamber, and this makes in the stopper 2 wedging chambeies 14, and formation closely cooperates, and therefore stopper 2 is solidly anchored to wherein.This can be clear that from Fig. 2 C.After stopper 2 is lax, inserts in the passage 6 of stopper 2 for the implant of screw 12 in this embodiment and be fixed in wherein.

Fig. 8 A to Fig. 8 D shows another embodiment that fixing device of the present invention is positioned at the fracture 16 that comprises fractures 20, and this fixing device comprises directed

SMP stopper

2a, 2b,

metal fastenings

12a, 12b, and plate 18.In this embodiment, by drilling through chamber 14a in fractures 20 both sides, 14b is prepared to bone 16 be used to accommodating fixing device.Chamber 14a, the size of 14b forms accommodates directed

stopper

2a and 2b.

Comprise that the plate 18 for accommodating

screw

12a and 12b that connects perforate 22a and 22b is placed in

stopper

2a and 2b, so that perforate 22a and 22b aim at opening 10a and the 10b of

stopper

2a and 2b respectively.

Each

stopper

2a, 2b is inserting chamber 14a, carries out orientation among the 14b before.In this embodiment, each

stopper

2a, 2b are all by stretching directed to it along its longitudinal axis.This causes

stopper

2a, and 2b is elongated, and its diameter narrows down.Also by making passage 6a, 6b stretches diametrically and is oriented in passage 6a, around the 6b for stopper 2a, 2b.This is by at first drilling through passage 6a, and 6b finishes, this passage 6a, and the diameter that 6b has is less than the screw 12a that is inserted into wherein, the diameter of the elongated shaft of 12b.Promote diameter greater than passage 6a, the pin (not shown) of 6b diameter is so that passage 6a, and 6b stretches diametrically.The diameter of pin equals or is slightly smaller than screw 12a, and the diameter of the elongated shaft of 12b is in order to make passage extend to suitable size to accommodate

screw

12a, 12b.

Plate 18 is placed on the fractures 20, so that in plate 18, be used for accommodating screw 12a, the perforate 22a of 12b, 22b and stopper 2a, the opening 10a of 2b and 10b aim at.Each

screw

12a, 12b are all via perforate 22a, and 22b inserts in the plate 18, and enters stopper 2a, and the path 6a of 2b among the 6b, thereby is fixed to stopper 2a with plate 18, on the 2b.For example be that it more effectively is incorporated in the path of stopper by screwing action in the situation of screw at securing member.Then, SMP makes stopper 2a by heating, and 2b is lax, causes

stopper

2a, and 2b radially expands towards its original shape.Stopper 2a, the expanded radially of 2b makes its wedging intracavity, and formation closely cooperates, and therefore with

stopper

2a, 2b is anchored in wherein securely, and therefore more securely fixing device is fixed on the fracture.SMP stopper lax also so that stopper 2a, the path 6a of 2b, 6b radially shrinks towards its original shape, so that path 6a, 6b is effectively with screw 12a, the axle clamp of 12b is held in wherein, thereby further fixing device is fixed on the bone.

Use heated probe 24 that heat is applied to stopper 2a, on the 2b, this heated probe 24 is applied directly to screw 12a, on the head of 12b.

Metallic screw

12a, 12b conducts heat along screw axis, and heat is led to and along stopper 2a, the length radiation of 2b.

For the performance of fixing device of the present invention is shown, has carried out test and come the anchoring strength of comparison fixing device and the anchoring strength of the bolt that normal screw is spirally connected.

Test A comprises that the bolt that the standard metal screw is spirally connected inserts stopper of the present invention.Stopper is formed by the SMP of mould drawing, and this SMP is by PLA-co-DL 70: 30 (65%wt) and CaCO ₃(35%wt) consist of.Stopper with bolt inserts in the bigger perforate of size in the model bone piece (Sawbones block) of 20 pounds/cubic feet (pcf), and then heats about 4 minutes so that stopper relaxes with 80 ℃ water.Test b has used stopper and the bolt with test A same type, but in this case, only stopper inserts in the bigger perforate of size and heats.After heating, then bolt is screwed in the stopper.Test C only comprises that the bolt with same type is inserted in the perforate of the same size that drills through in the model bone of 20pcf.All bolts are all pulled out from the model bone with the speed of 10mm/min.Provide in result's table 1 below, and show that the SMP stopper has improved the fixing of bolt.

Table 1

Test	Breaking load (N)
		A) heating bolt and cover	220
B) the heating cover is screwed into bolt	190
		C) be screwed into bolt, do not have cover	129

What recognize is,

stopper

2a, 2b can be oriented to so that passage 6a, and the slightly larger in diameter of 6b is in screw 12a, the diameter of the axle of 12b.As stopper inserted in the chamber, this allowed and need to less power come easily screw to be inserted in the stopper.Certainly, but be favourable in this and situation of promoting stopper or screw damaged bone or bone being broken very crisp at bone.

Now referring to Figure 11 a to Figure 11 d and Figure 12 a and Figure 12 d, partly show four samples of the bone with bone cavity 14, each chamber all has differently contoured.Directed shape memory stopper 2 is placed in each chamber 14, and this directed shape memory stopper 2 comprises PLLA-CO-DL and CaCO ₃Mixture (25mm length * 13mm external diameter) and comprise the metal fastenings 12 that diameter is 8mm.Use the heated probe of 4mm diameter with 175 ℃ each stopper 2 to be heated 15 minutes.In various situations, it is lax and be expanded in the profile in chamber 14 to observe SMP stopper 2.Then allow 2 coolings of SMP stopper, after this, the bed knife that measures is as follows:

Each bone sample that comprises lax stopper 2 as indicated above is placed on the cylindrical support on the lnstron 5566 test machine (not shown).The rigid metal probe that is connected to rigidly diameter on the 10kN load cell and is 8mm is extruded with 2mm/min against an end of stopper 2.Below table 2 in record and show in various situations power in order to the maximum of releasing stopper 2.

Table 2

Now referring to Figure 13, Figure 14 a and Figure 14 b, prepared the cylindrical SMP stopper 2 of two orientations, they have respectively the length of 25mm and the external diameter of 15mm.SMP stopper 2 shown in Figure 14 a is coated with PLC fiber 200 at its outside curved surface, and it is that 0.65mm is thick, and extends along SMP stopper 2 at the center, and has extended about 2/3 length of SMP stopper 2.The stopper 2 of the orientation shown in Figure 14 b does not comprise the PLC coating; In other side, it is identical with the SMP stopper 2 of Figure 14 a.The stopper 2 of the orientation among Figure 14 a and Figure 14 b all is placed in the bone cavity of 20PCF model bone piece, to produce respectively test sample book a and b.The degree of depth in the chamber in each sample is 40mm, and diameter is 18.78mm.Then, each sample immersed in about 90 ℃ hot water 10 minutes.Then, sample is immersed in the cold water and to cool off in 15 minutes.

With each sample section, and utilize optical microscope inspection, to determine the effect of PLC on SMP stopper-model bone piece interface.

Through observing, in the situation of the SMP stopper in Figure 14 a, the PLC coating melts, and when the SMP stopper was lax, PLC was pressed in the model bone piece, penetrates its hole, has improved the binding between SMP stopper and model bone piece.

In order further to study the effect of the SMP stopper with PLC coating, prepared the cylindrical SMP stopper of two orientations, they have respectively the length of diameter and the 27mm of 15mm.In various situations, the rustless steel cover inserts via center channel, and this center channel extends along the central longitudinal axis of SMP stopper.The rustless steel cover has the internal diameter of 4mm and the external diameter of 4.7mm.One of them SMP stopper is coated with the PLC fiber at the middle part of its outside curved surface, this coating extend SMP length about 2/3 and be that 0.65mm is thick.

Each SMP stopper is placed in the chamber of 20pcf model bone piece.The diameter in each chamber is 17.3mm, and the degree of depth is 40mm.Then, by being that the heated probe of 4mm is arranged in the rustless steel cover with diameter, make the SMP stopper lax.Probe was with 175 ℃ of heating 15 minutes.Then, take out probe, and allow that the SMP stopper is cooled to room temperature.

Then, use " release " test mechanically to test each SMP stopper.Model bone piece with SMP stopper is installed on the ring-shaped bearing piece, and then releases each SMP stopper with the Allen key with 8mm diameter with the speed of 1mm/min again.The peak force that each SMP stopper of record move is required, and therefore the anchoring of record destruction SMP stopper in the chamber links required peak force.In two kinds of situations, this all is so that the SMP stopper begins power mobile required in the chamber.In the following table 3 result has been shown.

Table 3

Sample	Peak value is released power
		SMP stopper (not comprising the PCL coating)	208N
SMP stopper (comprising the PCL fiber coat)	1586N

Find that the anchoring strength ratio that comprises the SMP stopper of PCL fiber coat is controlled strong by 662%.

What also recognize is, the SMP stopper also can be in inserting the chamber after but before inserting screw, relax.

What can envision is can use the securing member except orthopedic screw, for example nail or pin.In addition, although fixing device is particularly useful to the fractures of repairing in the very crisp bone, may not stand the arrangement of screw, nail or pin at very crisp os in os, or will really be applied to subsequently the power on it, but fixing device also can advantageously be applied on the normal bone.

What also can envision is that fixing device can comprise the stopper that does not have passage.This can make the surgeon for example can drill through the perforate of the size with specific requirement, thereby allows and select suitable screw, nail or pin.

What recognize is that the total length of the extensible stopper of passage gives the stopper tubular structure, or can extend along its part.Yet the length of passage must long enough, with the length of the axle that adapts to securing member.

What can envision is, comprises that the fixing device of external member or a whole set of part also can be assembled or partly assembling in advance, and this external member or a whole set of part comprise stopper, securing member and support unit.

Stopper, fixing device and applying method are not limited to above-described embodiment, but can change to some extent within the scope of the appended claims structure and details aspect.

Claims

1. fixture can expand when comprising in inserting bone cavity and is suitable for accommodating the stopper of securing member or implant, and described stopper comprises be used to the passage of accommodating described securing member, wherein,

Described stopper is lax so that described passage radially shrinks, so that described passage more closely is fixed in described securing member or implant wherein, thereby further described fixture is fixed to described bone cavity.

2. fixture according to claim 1 is characterized in that, described passage is positioned at the center of described stopper and along the longitudinal axis of described stopper.

3. fixture according to claim 1 is characterized in that, described stopper is included in the material that can change shape when receiving excitation.

4. fixture according to claim 1 is characterized in that, described stopper comprises shape-memory polymer or marmem, or the combination of marmem and shape-memory polymer.

5. fixture according to claim 1 is characterized in that, described stopper be porous or half porous.

6. fixture according to claim 1 is characterized in that, the outer surface of described stopper is coated with binding agent.

7. according to the described fixture of arbitrary aforementioned claim, it is characterized in that described stopper comprises outside cover or the coating of regulating, described outside adjusting cover or coating comprise biological activity element and/or mechanical adjustment element.

8. fixing device comprises such as claim 1 any one described fixture to the claim 7, and securing member.

9. fixing device according to claim 8 is characterized in that, described securing member comprises head and the elongated shaft of extending from described head, and the diameter of described head is less than or equal to the diameter of described stopper.

10. any one described fixing device to the claim 9 according to claim 8 is characterized in that described fixing device comprises support unit.

11. fixing device according to claim 10 is characterized in that, described support unit is plate.

12. fixing device according to claim 11 is characterized in that, described plate is general planar, perhaps is configured to adapt in order to the shape with the attached bone thereon of described plate.

13. fixing device according to claim 8 is characterized in that, described securing member is metal or nonmetallic, perhaps comprises shape-memory polymer, perhaps comprises marmem or their any combination.

14. fixing device according to claim 10 is characterized in that, described securing member and/or described support unit be porous or half porous.

15. a prothesis implant body comprises such as claim 1 any one described fixture to the claim 7.