CN219878383U - Pitch boat joint prosthesis - Google Patents

Abstract

The utility model relates to the technical field of medical equipment, in particular to a talarojoint prosthesis, which comprises a talus prosthesis, a liner and a navicular support prosthesis; the pad is arranged on one side of the talus prosthesis, and the navicular support prosthesis is arranged on one side of the pad away from the talus prosthesis; the contact surface of the talus prosthesis and the talus is designed with a clamping groove structure for fixation, and the contact surface of the navicular support prosthesis and the navicular is designed with a clamping groove structure for fixation, so that the initial loosening risk between the prosthesis and the contact bone is avoided, and the initial stability of implantation is improved; the utility model treats primary arthritis, post-traumatic arthritis or rheumatoid arthritis and other diseases by arranging the prosthesis, can keep the mobility of subtalar joints and tarsal transverse joints, reduce the occurrence of postoperative lameness of a patient, improve the gait of the patient after operation, reduce pain and improve the quality of life.

Description

Pitch boat joint prosthesis

Technical Field

The utility model relates to the technical field of medical instruments, in particular to a joint prosthesis of a talaroot.

Background

The lateral tarsal joints are formed by the union of the calcaneal cuboid joints and the talo-navicular joints, which are located on top of the arch, play an important role in the maintenance of the arch, and the talo-navicular joint arthritis causes persistent pain and dysfunction.

At present, for the treatment of primary arthritis of the talaroot joint, post-traumatic arthritis or rheumatoid arthritis, there is no other effective treatment means except for the treatment of the talaroot joint fusion, and although the talaroot joint fusion only involves a single joint, the complete loss of the activity of the subtalar joint and the lateral tarsal joint can be almost caused in biomechanics, and the existing treatment means of the clinical talaroot joint are all the main treatment means of sacrificing the activity of the talaroot joint (fusing the talaroot joint), and the occurrence of lameness after operation of a patient is easy to be caused, so a new medical instrument is needed for treating the primary arthritis, the post-traumatic arthritis or the rheumatoid arthritis and other diseases so as to keep the activity of the subtalar joint and the lateral tarsal joint.

Disclosure of Invention

The utility model aims to provide a talarojoint prosthesis which is used for treating primary arthritis, post-traumatic arthritis or rheumatoid arthritis and other diseases and can keep the mobility of subtalar joints and tarsal joints.

To achieve the above objects, the present utility model provides a talarojoint prosthesis comprising a talus prosthesis, a liner and a navicular tray prosthesis;

the spacer is disposed on a side of the talus prosthesis and the navicular support prosthesis is disposed on a side of the spacer remote from the talus prosthesis.

Wherein the talar prosthesis has a talar spherical outer convex surface, a porous inner concave surface, and two first posts;

the talar spherical outer convex surface is positioned on the side of the talar prosthesis, which is close to the pad, the porous inner concave surface is positioned on the side of the talar prosthesis, which is far away from the talar spherical outer convex surface, and the two first upright posts are positioned on the side of the porous inner concave surface, which is far away from the pad.

The navicular bone support prosthesis is provided with a navicular bone porous spherical outer convex surface, two second upright posts and an inner concave surface;

the porous spherical outer convex surface of the navicular bone is positioned on one side of the navicular bone support prosthesis away from the pad; the two second upright posts are positioned on one side of the porous spherical outer convex surface of the navicular bone; the concave surface is positioned on one side of the navicular support prosthesis, which is close to the pad.

Wherein the pad has an outer convex surface and an inner concave spherical surface;

the convex surface is positioned on the side of the pad adjacent to the concave surface, and the concave spherical surface is positioned on the side of the pad adjacent to the convex surface of the talus ball.

Wherein the talus prosthesis is made of a metallic material.

Wherein the liner is made of high polymer materials including, but not limited to, ultra-high molecular weight polyethylene and polyetheretherketone.

Wherein, the navicular bone support prosthesis is made of metal materials.

A talar joint prosthesis of the present utility model is generally made of a metallic material and has a variety of designs for the contact surface with the talus, including but not limited to: the surface in contact with the pad is a spherical smooth surface, so that friction with the surface of the pad is reduced; the liner is generally made of a high polymer material, including but not limited to ultra-high molecular weight polyethylene, polyether ether ketone and the like, the contact surface of the liner and the talus prosthesis is a spherical smooth surface, and the other side of the liner is fixed with the podophyllotoxin prosthesis in a mechanical assembly fixing mode and a compound fixing mode (explanation is that the compound fixing mode generally refers to a connecting mode of a porous structure and an injection molding body, fluid enters pores of the porous structure during injection molding, and the fluid is fixed with the porous structure after solidification). The navicular support prosthesis is typically made of a metallic material and has a number of design variations on the navicular contact surface including, but not limited to: the other side of the navicular support prosthesis is fixed with the pad by the rough surface, the spraying, the porous structure, the spraying and the like, and the fixing modes include but are not limited to mechanical assembly fixing and compound fixing.

The contact surface of the talus prosthesis and the talus is designed with a clamping groove structure for fixation, and the contact surface of the navicular support prosthesis and the navicular is designed with a clamping groove structure for fixation, so that the initial loosening risk between the prosthesis and the contact bone is avoided, and the initial stability of implantation is improved; long-term stabilization of talus prostheses and navicular support prostheses is achieved by virtue of bone ingrowth of the surface of an abutment prosthesis and the surface of the abutment prosthesis, which is in direct contact with bone, and the designs of surface roughness of the prosthesis, spray coating/porous structure, spray coating and the like can promote bone ingrowth and angiogenesis, so that long-term stability of the prosthesis and the contacted bone is improved. In addition, the clamping groove structure is designed between the liner and the navicular support for fixing so as to realize initial stability and long-term stability, and the three parts of the navicular prosthesis in the conventional combined mode are designed to be in a ball-and-socket structure, so that the initial stability and long-term stability of the prosthesis can be improved. The utility model treats primary arthritis, post-traumatic arthritis or rheumatoid arthritis and other diseases by arranging the prosthesis, can keep the mobility of the subtalar joint and the tarsal joint, reduce the occurrence of postoperative lameness of a patient, improve the gait of the patient after operation, relieve pain and improve the quality of life.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

Figure 1 is a schematic representation of foot motions.

Fig. 2 is a flow chart of the design of the talarojoint prosthesis of the present utility model.

Fig. 3 is an azimuthal view of the direction of implantation of the prosthesis according to the first aspect of the present utility model.

Fig. 4 is a schematic view of a joint-to-boat fit.

Fig. 5 is a schematic view showing the structure of a talarojoint prosthesis according to the first aspect of the present utility model.

Fig. 6 is a schematic view of the structure of a talus prosthesis according to a first aspect of the present utility model.

Fig. 7 is a schematic view of a structure of a navicular tray prosthesis according to the present utility model.

Fig. 8 is a schematic view of the structure of a pad and navicular rest prosthesis according to the present utility model.

Fig. 9 is a schematic view of an osteotomy according to a first aspect of the present utility model.

Fig. 10 is a schematic view of a prosthesis implantation according to a first embodiment of the present utility model.

Fig. 11 is an azimuthal view of the direction of implantation of the prosthesis according to the second aspect of the present utility model.

Fig. 12 is a schematic structural view of a case two of a talarojoint prosthesis according to the present utility model.

Fig. 13 is a schematic view of the structure of a talar prosthesis of the present utility model in case two.

Fig. 14 is a schematic view of a medial access talar prosthesis design model of the present utility model implanted on the talus head.

Fig. 15 is a schematic view of a medial approach design model of a navicular tray prosthesis according to the second aspect of the present utility model.

Fig. 16 is a schematic diagram of a design model of a navicular tray prosthesis and a spacer prosthesis according to the second aspect of the present utility model.

FIG. 17 is a schematic view of a talar-navicular osteotomy design in accordance with scenario two of the present utility model.

Fig. 18 is a schematic view of a medial approach of a talar joint prosthesis according to the second aspect of the utility model after implantation.

1-talus prosthesis, 2-pad, 3-navicular tray prosthesis, 11-talus spherical outer convex surface, 12-porous inner concave surface, 13-first upright post, 21-outer convex surface, 22-inner concave spherical surface, 31-navicular porous spherical outer convex surface, 32-second upright post, 33-inner concave surface.

Detailed Description

Referring to fig. 1-18, the present utility model provides a talarojoint prosthesis comprising a talus prosthesis 1, a liner 2 and a navicular support prosthesis 3; the scheme can be used for treating primary arthritis, post-traumatic arthritis or rheumatoid arthritis and other diseases, and can maintain the mobility of subtalar joints and tarsal transverse joints.

For this embodiment, the spacer 2 is arranged on the side of the talus prosthesis 1 and the navicular prosthesis 3 is arranged on the side of the spacer 2 remote from the talus prosthesis 1. The talar prosthesis 1 is typically made of a metallic material and has a variety of designs for the talar interface, including but not limited to: the contact surface of the surface with the liner 2 is a spherical smooth surface, so as to reduce friction with the surface of the liner 2; the liner 2 is generally made of a high polymer material, including but not limited to ultra-high molecular weight polyethylene, polyether ether ketone, etc., the contact surface with the talus prosthesis 1 is a spherical smooth surface, and the other side of the liner 2 is fixed with the navicular bone supporting prosthesis 3 by mechanical assembly and compound fixation (explanation: compound fixation generally refers to a connection mode of a porous structure and an injection molding body, fluid enters pores of the porous structure during injection molding, and the fluid forms fixation with the porous structure after solidification). The navicular support prosthesis 3 is typically made of a metallic material and has a number of design variations on the navicular contact surface including, but not limited to: rough surface, rough surface + spray, porous structure and porous structure + spray, etc., the other side of the navicular support prosthesis 3 is secured to the liner 2 by means including, but not limited to, mechanical assembly and compound fixation.

The contact surface of the talus prosthesis 1 and the talus is designed with a clamping groove structure for fixing or a prosthesis withdrawal preventing screw design (designed according to actual needs), the contact surface of the navicular support prosthesis 3 and the navicular is designed with a clamping groove structure for fixing, the initial loosening risk between the prosthesis and the contact bone is avoided, and the initial implantation stability is improved; long-term stabilization of the talus prosthesis 1 and the navicular support prosthesis 3 is achieved by virtue of the fact that the surface of the graft prosthesis directly contacts with the bone ingrowth of the bone surface, and the designs of the surface roughness of the prosthesis, the spraying/the porous structure, the spraying and the like can promote the bone ingrowth and the angiogenesis, so that the long-term stability of the prosthesis and the contacted bone is improved. In addition, the clamping groove structure is designed between the liner 2 and the navicular support for fixing so as to realize initial stability and long-term stability, and the three parts of the navicular prosthesis in the conventional combined mode are designed to be in a ball-and-socket structure, so that the initial stability and long-term stability of the prosthesis can be improved.

The reduced impact of the design of the talaroot prosthesis on the talaroot joint mobility may be ensured from the following aspects:

1) The talar-navicular anatomy approximates a ball and socket structure, talar-navicular joint mobility, as shown in fig. 1. Relative motion of about 18 ° in plantarflexion/dorsiflexion (X direction), about 32 ° in varus/valgus (Y direction), and about 28 ° in abduction/adduction (Z direction). The talarojoint prosthesis is designed into a ball-and-socket structure which is close to the talarojoint anatomy structure, and the motion characteristics of the original anatomy structure are restored to the greatest extent. The ball and socket arrangement is advantageous in that it maximizes the range of articulation over which the navicular joint prosthesis is implanted.

2) Another advantage of the design of the talarojoint prosthesis as a ball and socket structure is that it reduces the osteotomy of the talus and navicular bones, maintains good blood supply to the talus and navicular bones, allows rapid growth of new bone on the surface where bone ingrowth is designed after implantation of the prosthesis, shares load with the prosthesis, improves long-term stability of the prosthesis and prolongs the service life of the prosthesis.

3) The design size of the navicular joint prosthesis is smaller than the size of the navicular joint anatomy, and the design size has the advantage of reducing the damage to navicular bones and talus bone structures and the damage and stripping of surrounding ligaments and soft tissues. The less the prosthetic implant affects the soft tissue surrounding the primary foci-navicular joint anatomy, the less the surrounding ligaments are damaged, and the less the primary joint mobility is affected.

The surgical approach for the implantation of the talarojoint prosthesis was selected as follows:

the talo-navicular joint is positioned at the top of the arch, and the operation access way for implanting the talo-navicular joint prosthesis is preferably selected from a dorsal access way, a dorsal access way and a medial access way, and has the following advantages: the soft tissue on the back side of the joint is shallower, no muscle passes through, and the joint can be directly exposed after the skin and a small amount of soft tissue are cut. The peri-navicular ligaments are extremely important for the stability of the arch and the peri-navicular joints, the medial and bottom of the navicular bones are provided with calcaneal plantar ligaments (spring ligaments), the medial tuberosity of the navicular bones is provided with a dead center of the tibialis posterior, the tibialis ligament (bundle of triangular ligaments) is arranged above the dead center, the dorsal side is the dorsal ligament of the peri-navicular joints, and the lateral side of the navicular bones is the calcaneal-navicular bifurcation ligament. Among the peri-navicular ligaments, there are two possible cases of prosthesis implantation paths, with minimal impact on the motion of the navicular joint, one is to resect the posterior ligament of the navicular joint, implanting the prosthesis in a direction proximal to the posterior; and secondly, the tibial navicular ligament of the triangular ligament is resected, and the prosthesis is implanted in the medial direction.

The utility model treats primary arthritis, post-traumatic arthritis or rheumatoid arthritis and other diseases by arranging the prosthesis, can keep the mobility of the subtalar joint and the tarsal joint, reduce the occurrence of postoperative lameness of a patient, improve the gait of the patient after operation, relieve pain and improve the quality of life.

Wherein the talar prosthesis 1 has a talar spherical outer convex surface 11, a porous inner concave surface 12 and two first uprights 13; the talus spherical outer convex surface 11 is located on the side of the talus prosthesis 1 which is close to the pad 2, the porous inner concave surface 12 is located on the side of the talus prosthesis 1 which is away from the talus spherical outer convex surface 11, and the two first upright posts 13 are located on the side of the porous inner concave surface 12 which is away from the pad 2. The talar spherical outer convex surface 11 to reduce wear on the pad 2; the porous concave surface 12 can reduce osteotomies from bones and distribute loads to a larger area through the concave design, the 1-2mm thick porous design of the porous concave surface 12 and the two first upright posts 13 can provide initial implantation friction stability, and initial implantation stability is improved; meanwhile, the concave surface of the porous design is in direct contact with the cut human talus, so that the ingrowth of talus tissues is facilitated, and the long-term stability of the implanted prosthesis is improved.

Second, the navicular support prosthesis 3 has a navicular porous spherical outer convex surface 31, two second posts 32 and an inner concave surface 33; the navicular porous spherical outer convex surface 31 is positioned on the side of the navicular support prosthesis 3 remote from the liner 2; two second upright posts 32 are positioned on one side of the navicular porous spherical outer convex surface 31; the concave surface 33 is located on the side of the navicular support prosthesis 3 adjacent to the insert 2. The design of the porous spherical outer convex surface 31 of the navicular bone can increase the contact area between the navicular bone support prosthesis 3 and the navicular bone, in addition, the porous design of the porous spherical outer convex surface 31 of the navicular bone with the thickness of 1-2mm and two second upright posts 32 can provide the friction stability of initial implantation and improve the initial stability of the prosthesis implantation; meanwhile, the porous inner concave surface 33 is in direct contact with the cut human navicular bone, so that the ingrowth of navicular bone tissues is facilitated, and the long-term stability of the implanted prosthesis is improved.

Meanwhile, the pad 2 has an outer convex surface 21 and an inner concave spherical surface 22; the outer convex surface 21 is located on the side of the pad 2 adjacent to the inner concave surface 33 and the inner concave spherical surface 22 is located on the side of the pad 2 adjacent to the talar spherical outer convex surface 11. The outer convex surface 21 is matched with the inner concave surface 33 of the navicular support prosthesis 3, so that the stability of the fixation of the liner 2 and the navicular support prosthesis 3 is improved; the other side of the pad 2 is designed with a concave spherical surface 22 that contacts the talar spherical outer convex surface 11 of the talar prosthesis 1, the concave spherical surface 22 of the pad 2 being smooth to reduce friction with the smooth talar spherical outer convex surface 11 of the talar prosthesis 1.

The utility model relates to a joint prosthesis of a talaroot, which mainly comprises the following design flow: the prosthesis implantation direction, the talar-navicular joint fit, the talus head design, the navicular support design, the spacer 2 design and the osteotomy design are determined. When the implantation direction of the prosthesis is determined and the joint fitting circle of the talar-navicular joint is made, firstly, the force line of the tibia is determined and used as the Z axis of the system, then the axis of the talus bone, the first metatarsal bone and the Z axis are determined, the axis intersects at the O point and is used as the origin of the coordinate axis, the positive direction of the X axis is vertical to the external direction of the Z axis, and the positive direction of the Y axis is vertical to the anterior direction of the Z axis. The implantation direction of the prosthesis is determined according to CT data of the coronal plane and the sagittal plane and two implantation modes of the prosthesis. And (3) making a fitting circle of the joint of the talus-navicular along the implantation direction, wherein the center of the fitting circle is used as the sphere center position of the structural design of the prosthetic ball socket.

The talar head design mainly includes a spherical articular surface design/an initial fixation design/an ingrowth design. The navicular tray design mainly includes a bone ingrowth design/an initial fixation design/a fixation design with the cushion 2. The cushion 2 design mainly includes a spherical articular surface design and a fixation with the navicular plate design. The osteotomy design is mainly talus head osteotomy design and navicular bone osteotomy design.

The following provides a detailed description of the technical solution for the implantation of the two prostheses described above (i.e. the fixation of the clamping groove structure of the utility model shown in fig. 5-8, and the talus prosthesis 1 of the prosthetic anti-withdrawal screw design shown in fig. 12-13, 15-16):

1-10, the specific steps for determining the implant direction (dorsal approach) of the prosthesis using a fixed prosthesis with a bayonet structure are:

1. and determining the tibia force line Z axis, and keeping away from the ground to be positive. The talus-first metatarsal axis OY1 is determined to intersect the Z axis at point O, with the vertical Z axis outward being the X-axis forward direction and the vertical XOZ plane forward being the Y-axis forward direction.

2. The coronal plane measures the angle between the top plane of the navicular bone of the foot and the Z axis, and the angle between the navicular joint and the X OZ plane is determined and used as the implantation direction P1 of the prosthesis, and the acute angle between the implantation direction of the prosthesis and the positive angle between the Z axis is alpha.

3. The sagittal plane determines that the OY1 axis coincides with the prosthesis axis, determines the angle of the talar-navicular joint in the YOZ plane, and is used as the prosthesis implantation direction P2, and the acute angle between the prosthesis implantation direction and the Y-axis forward direction is beta.

4. After the determination steps 2 and 3, the final direction of implantation of the prosthesis along the dorsal approach in three dimensions is determined.

The specific steps of the joint fitting of the talar-navicular joint are as follows:

1. after determining the prosthesis implantation direction P1, a fitting circle 1 of the joint space of the distance-boat is made in the direction, and the center position W1 of the fitting circle on the plane of the OP1 direction is determined, as shown in fig. 4 (a).

2. Fitting circle 2 of the joint space of the distance-boat is made in the direction of the body implantation direction P2, and the position W2 of the center of the circle of the fitting circle 2 in the direction OP2 is determined as shown in fig. 4 (b).

3. And (3) taking the fitting circle 1 determined in the step (1) as a rotated object, and sweeping along the fitting circle 2 to finally obtain the fitting sphere center position and the fitting sphere shape of the joint of the talaroot.

The specific steps of the design of the joint prosthesis of the talaroot are as follows:

referring to fig. 5-8, the talarojoint prosthesis consists of a talus prosthesis 1, a spacer 2, and a navicular support prosthesis 3.

In fig. 5, the talar prosthesis 1 has a talar spherical outer convex surface 11, a porous inner concave surface 12 and two first uprights 13, manufactured integrally by 1. Selective Laser Melting (SLM) or selective Electron Beam Melting (EBM); or 2. Porous concave surface 12 fabrication is achieved on talar prosthesis 1 in a sintering process. The navicular support prosthesis 3 in fig. 5 has a navicular porous spherical outer convex surface 31, two second uprights 32 and an inner concave surface 33, and is integrally manufactured by Selective Laser Melting (SLM) or selective Electron Beam Melting (EBM); or 2. The manufacture of the navicular porous spherical outer convex surface 31 of the navicular support prosthesis 3 is achieved on the navicular support prosthesis 3 in a sintering process. In addition, the inner concave surface 33 and the outer convex surface 21 of the pad 2 in fig. 5 are two structures of two parts, and the fixing manner of the two parts includes, but is not limited to, a mechanical assembly fixing connection manner of the clamping groove, and other mechanical fixing manners or compound fixing manners (such as the prosthesis using the prosthesis anti-withdrawal screw shown in fig. 12-13 and 15-16).

The talus prosthesis 1 has a surface thickness of 1-2mm which is a porous concave surface 12 and a solid structure inside. The porous concave surface 12 is provided with two parallel first upright posts 13, and the first upright posts 13 are directly connected with the porous concave surface 12. The square first post 13 facilitates initial fixation during implantation, preventing the talar prosthesis 1 from falling off the talar side and wobble.

The thickness of the surface of the navicular support prosthesis 3 is 1-2mm, the surface 31 is a navicular porous spherical outer convex surface, and the inside is a solid structure. Two parallel square second upright posts 32 are designed on the porous spherical outer convex surface 31 of the navicular bone, and the second upright posts 32 are directly connected with the porous spherical outer convex surface 31 of the navicular bone. The square second upright 32 facilitates initial fixation during implantation, preventing the navicular support prosthesis 3 from falling off and rocking from the navicular side.

The specific steps of osteotomy design are as follows:

fig. 9 is a design view of a talar-navicular osteotomy, with the leftmost view in fig. 9 being a schematic view of a talar-navicular osteotomy, the middle view being a schematic view of a talar head osteotomy, and the rightmost view being a schematic view of a navicular osteotomy. The talar-navicular osteotomies are mainly divided into talar head osteotomies and navicular foot osteotomies. The talar osteotomy is a convex outer surface contour osteotomy around the talar head, and the groove osteotomy matched with the two square second upright posts 32 of the talar prosthesis 1 is cut, so that the contact area between the talar prosthesis 1 and the talar is increased while the talar osteotomy amount is reduced, and the bone ingrowth amount is increased, and the initial stability and the long-term stability are improved;

the navicular osteotomy is a groove osteotomy which surrounds the outline of the navicular concave joint surface and is matched with the two square second upright posts 32 of the navicular bracket prosthesis 3; viewed on a sagittal plane, the osteotomy incompletely resects the concave joint surface of the navicular bone, and the osteotomy reaches between 3/5 and 4/5 of the concave joint surface, as shown in fig. 10; viewed in the direction of prosthetic implantation, 3/5 of the medial aspect of the navicular concave articular surface is taken as shown in FIG. 10. The contact area between the navicular support prosthesis 3 and the navicular is increased while the navicular osteotomy is reduced, so as to increase the bone ingrowth amount, improve the initial stability and the long-term stability.

The specific steps of the implantation of the joint prosthesis of the talaroot are as follows:

fig. 10 is a schematic view of the implantation of a talarojoint prosthesis, the left side of fig. 10 being a view of the direction of the prosthesis implantation, and the right side being a view of the sagittal plane. The prosthesis is observed to be in a concentric circle structure in the implantation direction of the prosthesis, so that the stability of the talaroot joint after the implantation of the talaroot joint prosthesis is enhanced. Viewed in the sagittal plane, the navicular support prosthesis 3 is located 3/5-4/5 of the dorsal aspect of the navicular concave joint, with the talus prosthesis 1 fully covering and being located on the talus head. The circumferential profile of the talar prosthesis 1 is greater than the circumferential profile of the spacer 2 to promote the mobility of the talar-navicular joint after implantation of the talar prosthesis.

In a second case, referring to fig. 11 to 18, the specific steps for determining the implantation direction (inner approach) of the prosthesis using the prosthesis with the withdrawal-preventing screw are:

the method has the similarity with the implantation direction of the prosthesis determined by the dorsi-medial implantation way, but has the difference that the implantation direction of the prosthesis is determined by the medial implantation way as follows:

1. and determining the tibia force line Z axis, and keeping away from the ground to be positive. The talus-first metatarsal axis OY1 is determined to intersect the Z-axis at point O, with the vertical Z-axis outward being the X-axis forward direction and the vertical XOZ-plane forward being the Y-axis forward direction (coincident with the dorsally medial approach).

2. The coronal plane measures the angle between the top plane of the navicular bone and the Z axis, determines the angle between the talus-navicular joint and the XOZ plane, and is used as the fitting direction P1 of the prosthesis, and the acute angle between the implantation direction of the prosthesis and the Z axis is alpha (different from the dorsum inner side approach).

3. The sagittal plane determines that the OY1 axis coincides with the prosthesis axis, determines the angle of the talar-navicular joint in the YOZ plane, and is taken as the prosthesis implantation direction P2, and the acute angle between the prosthesis implantation direction and the Y-axis forward direction is beta (consistent with the dorsally-medial approach).

4. After determining the implantation direction P2, the rotation (right hand rule) by an angle γ (80 ° to 100 °) along the OY1 axis results in the implantation direction P3 of the prosthesis inner approach, as shown in fig. 11 (c).

5. After the determination steps 3 and 4, the final direction of implantation of the prosthesis along the three-dimensional space of the medial approach is determined.

The specific steps of the joint fitting of the talar-navicular joint are as follows:

the fitting of the talo-navicular joint surfaces is irrelevant to the implantation of the prosthesis, and the fitting step of the talo-navicular joint of the inner implantation is completely consistent with the fitting step of the dorsi-medial implantation.

The medial approach design of the talar-navicular prosthesis is similar to that of the dorsal medial approach, fig. 12a is a schematic view of the assembled prosthesis, fig. 12b is a porous structure of the talar prosthesis 1 in direct contact with bone, fig. 12c is a solid structure of the talar prosthesis 1 in contact with the liner 2, fig. 12d is a liner 2 structure, fig. 12e is a solid structure of the mechanical connection of the navicular support and the liner 2, and fig. 12f is a porous structure of the navicular support in direct contact with the navicular bone. In addition, the design of a prosthesis holding device and the like can be added on the prosthesis, so that the implantation and the extraction of the prosthesis are more convenient.

The medial approach distance-navicular joint prosthesis differs in design from the posterior medial approach prosthesis, specifically, as follows:

a) An anti-withdrawal structure is designed at the medial edge of the talar prosthesis 1 to secure the talar prosthesis 1 to the talar such that the prosthesis does not withdraw medially, as shown in fig. 12 c.

b) The porous structure of the navicular support is designed with a direction column (parallel to the implantation direction) to reduce the osteotomy of the navicular, as shown in fig. 12 f.

The specific steps of talus head design are:

the medial approach talus prosthesis 1 is also designed with a solid + porous structure combination, as shown in fig. 13.

FIG. 14 is a schematic view of the implantation of a design model of a medial access talar prosthesis 1 onto the talus head, with a smooth spherical outer convex surface on one side of the talus head to reduce wear on the liner 2; the other side of the talus head is provided with two square upright post structures (other structures capable of realizing initial stability can be designed), two anti-withdrawal screw holes are designed near the inner side, and the implantable screw can realize the function of preventing the talus prosthesis 1 from withdrawing (the anti-withdrawal design can be adjusted to other structures, and the final effect is that the prosthesis is provided with the anti-withdrawal function).

The design method of the navicular bone support comprises the following specific steps:

fig. 15 is a schematic view of a design model of a medial approach for a navicular support prosthesis, which is also designed in a solid + porous structure combination.

The prosthetic foot navicular support prosthesis is different from the prosthetic foot prosthesis with the dorsal medial approach, and the prosthetic foot navicular support prosthesis with the medial approach adopts a single square upright post (can be designed into other structures which are matched with the navicular bone to realize initial fixation), so that the contact area of the navicular support and the navicular bone can be increased while the damage to the original osseous structure of the navicular bone is reduced, and the initial stability of the prosthetic foot support prosthesis and the osseous structure is enhanced. In addition, the porous structure contacted with the navicular bone can be designed into an outer convex surface or a plane, so that the surface of the porous prosthesis is matched with the navicular bone structural surface.

The side to which the pad 2 is attached is designed with mechanical attachment structures including, but not limited to, bar-type stud structures on the schematic illustration.

The specific steps of the design of the liner 2 are as follows:

fig. 16 is a schematic diagram of a design model of a navicular support prosthesis and a liner 2 prosthesis, the matching relationship between the two surfaces including but not limited to: one side of the pad 2 is provided with a convex design, the convex design is matched with the concave navicular support prosthesis, and the stability of the pad 2 and the navicular support prosthesis is improved.

The other side of the pad 2 is of concave spherical design, in contact with the smooth spherical outer convex surface of the talar prosthesis 1. The concave spherical surface of the liner 2 prosthesis is smooth to reduce friction with the smooth spherical outer convex surface of the talar prosthesis 1.

The specific steps of osteotomy design are as follows:

fig. 17 is a schematic view of a talar-navicular osteotomy, which is largely divided into talar head osteotomies and navicular foot osteotomies. The bone osteotomies are plane osteotomies with convex outer surface contours around the talus head as shown in fig. 9 or 17, groove osteotomies matched with two square upright posts of the talus prosthesis can be cut, the contact area between the talus prosthesis and the talus is increased while the talus osteotomies are reduced, and therefore the bone ingrowth amount is increased, and initial stability and long-term stability are improved.

The navicular bone is resected from the direction of the prosthetic implant, as shown in fig. 17, with the resected surface conforming to the navicular bone supporting prosthesis surface. The osteotomy depth is 3/5-4/5 of the longest dimension of the whole navicular bone, so as to ensure that the bifurcation ligament at the outer side is not destroyed; the osteotomy width is 2/5-3/5 of the height of the upper and lower parts, so that enough bone mass of plantar ligaments on the plantar side of the calcanenavicular bone and the navicular ligaments on the dorsal side can be ensured, and the navicular joint can stably move after the prosthesis is implanted.

Fig. 18 is a schematic view of the prosthetic medial approach of the talaroot after implantation, wherein the prosthetic medial approach is seen to have a concentric circular configuration in the prosthetic implantation direction, enhancing the stability of the talaroot after implantation. The effect of the implanted prosthesis is observed from the cross section, the bone structure on the back side of the talaroot joint is well preserved, the damage to the bone structure and the soft tissue structure on the back side of the talaroot joint after the implantation of the prosthesis is small, the influence of the implantation of the prosthesis in the inner side implantation way on the back side of the talaroot joint is little, and the influence of the implantation of the prosthesis on the movement of the primary talaroot joint can be reduced.

The inner side of the talus prosthesis 1 is provided with an anti-withdrawal structure, the initial anti-withdrawal function can be realized by the anti-withdrawal structure after the prosthesis is implanted, and the long-term anti-withdrawal fixing function of the prosthesis can be realized after bone grows into a porous structure on the prosthesis.

The talarojoint prosthesis can be suitable for primary arthritis, post-traumatic arthritis or rheumatoid arthritis and other diseases, can keep the mobility of the subtalar joint and the tarsal transverse joint, reduce the occurrence of postoperative lameness of a patient, improve the postoperative gait of the patient, relieve pain and improve the quality of life.

The foregoing disclosure is only illustrative of one or more preferred embodiments of the present utility model, and it is not intended to limit the scope of the claims hereof, as persons of ordinary skill in the art will understand that all or part of the processes for practicing the embodiments described herein may be practiced with equivalent variations in the claims, which are within the scope of the utility model.

Claims (4)

1. A joint prosthesis of a talaroot is characterized in that,

including talus prostheses, liners, and navicular tray prostheses;

the pad is arranged on one side of the talus prosthesis, and the navicular support prosthesis is arranged on one side of the pad away from the talus prosthesis; the talar prosthesis has a talar spherical outer convex surface, a porous inner concave surface, and two first posts; the talar prosthesis comprises a liner, a talar prosthesis, a porous concave surface, a first upright and a second upright, wherein the talar prosthesis is provided with a spherical convex surface, the spherical convex surface of the talar prosthesis is positioned on one side close to the liner, the porous concave surface is positioned on one side of the talar prosthesis away from the spherical convex surface of the talar, and the two first upright are positioned on one side of the porous concave surface away from the liner; the navicular bone support prosthesis is provided with a navicular bone porous spherical outer convex surface, two second upright posts and an inner concave surface; the porous spherical outer convex surface of the navicular bone is positioned on one side of the navicular bone support prosthesis away from the pad; the two second upright posts are positioned on one side of the porous spherical outer convex surface of the navicular bone; the inner concave surface is positioned at one side of the navicular support prosthesis close to the pad; the pad has an outer convex surface and an inner concave spherical surface; the convex surface is positioned on the side of the pad adjacent to the concave surface, and the concave spherical surface is positioned on the side of the pad adjacent to the convex surface of the talus ball.

2. The joint prosthesis of claim 1, wherein,

the talus prosthesis is made of a metallic material.

3. The joint prosthesis of claim 1, wherein,

the liner is made of high polymer materials, and the high polymer materials comprise ultra-high molecular weight polyethylene and polyether-ether-ketone.

4. The joint prosthesis of claim 1, wherein,

the navicular bone support prosthesis is made of metal materials.