CN203447389U

CN203447389U - Knee joint tibia support of asymmetric structure

Info

Publication number: CN203447389U
Application number: CN201320468609.2U
Authority: CN
Inventors: 吴海山; 王建平; 曹庆宏; 赵辉; 金航军; 沈陆
Original assignee: THYTEC SHANGHAI CO Ltd
Current assignee: THYTEC SHANGHAI CO Ltd
Priority date: 2013-08-01
Filing date: 2013-08-01
Publication date: 2014-02-26
Anticipated expiration: 2023-08-01

Abstract

The utility model discloses a knee joint tibia support of an asymmetric structure in the technical field of medical instrument total knee prostheses. The knee joint tibia support comprises a connecting table, an insertion body and a reinforcing piece arranged between the connecting table and the insertion body, wherein the connecting table is fixedly connected with the insertion body. Because the reinforcing piece is additionally arranged on the knee joint tibia support, pressure stress and shear force which are generated by the relative motion of femurs and tibias of a human body can be better borne by the knee joint tibia support of the asymmetric structure, bone tissue ankylosing is better facilitated, and knee joint interface stability is improved.

Description

The knee joint tibia support of unsymmetric structure

Technical field

The utility model relates to the device of medical apparatus and instruments artificial knee joint technical field, specifically a kind of knee joint tibia support of unsymmetric structure.

Background technology

In clinical treatment engineering field, have the design form of multiclass artificial knee joint, domestic used artificial knee joint prosthesis be take design abroad as main at present; For the structural design of artificial knee joint prosthesis, the 3 dimensional coil geometry of tibia support design is one of compatriots' key factor of implementing total knee replacement success or not.Tibia support directly inserts in the trabecular bone structure of human tibia platform, completes the fixing of tibial plateau and tibia support.The quality of the three dimensional structure design of tibia support directly affects growth and the combination of artificial knee joint tibial component and human tibia.

There are many types in the three-dimensional geometry profile of artificial knee joint tibia support, mostly is design abroad.After deliberation and statistics, the design form of tibia support mostly is symmetric design, and the femur of human body knee joint and the relative motion of tibia are different at interior lateral condyle, and its stress is also different with stress distribution, the wing of tibia support inserts in the trabecular bone structure of human tibia platform simultaneously, play the fixation of tibial plateau and tibia support, its fixation and with the quality of osseous tissue ankylose, directly affect kneed interface stability.Tibia support aseptic loosening is modal failure cause after knee prosthesis.Because proximal tibia bone amount is less, initial tibia support is designed with stem in a marrow and resists the inclination of implant and be lifted away from.In this marrow, stem can arrive proximal tibia compressive stress and shear transfer in far-end spongy bone, but may be weak because of spongy bone nearer end herein, thereby may be inclined to fracture.The compressive stress of distal femur maximum can reach 2.5 times of body weight, the shearing force of 0.5 times, and the compressive stress that this distal femur is born when walking can reach 3 times of body weight.And in kneed whole flexing process, knee joint shin femoral joint is mainly in interior side contacts interaction, especially obvious when high flexing, therefore, in knee-joint prosthesis bears a heavy burden, larger compressive stress and shearing force will be born compared with outside in inner side.

Through the literature search of prior art is found, Chinese patent literature CN102232883A day for announcing 2011-11-09 has recorded a kind of knee joint rotating platform prosthesis, comprise tibia support and tibia pad, wherein: the lower surface of the upper surface of described tibia support and tibia pad is plane, tibia support upper surface is provided with two to three limited posts, and one of them limited post is main limited post; The edge, lower surface of tibia pad is provided with corresponding opening stopper slot, and one of them stopper slot is main stopper slot; Each limited post is separately positioned in corresponding stopper slot, main limited post moves with corresponding stopper slot fore-and-aft direction, the spacing connection of above-below direction, other limited posts can move in corresponding stopper slot, and the inner distance of main stopper slot opening part and other stopper slots is less than the distance between main limited post and other limited posts.But tibia support is only used support stick to strengthen its intensity in this technology, permanent use may cause the failure phenomenon of the dislocation, fracture of the unstable and artificial knee joint prosthesis at artificial knee joint interface etc.

Chinese patent literature CN202154767U, the day for announcing 20120307, a kind of low abrasion loss artificial tibial platform prosthesis is disclosed, include sealed post, sealed, band wing fixed leg, sealed cornice has taper design, and be designed with the small stair that prevents that High molecular weight polyethylene pad from coming off, be embedded in High molecular weight polyethylene tibial insert, sealed adopts machining to form, dimensional accuracy is higher, and surface adopts high polishing, contact and it is played a supportive role with high molecular tibial insert, band wing fixed leg is implant into body pulp cavity directly, also can connect after extension bar assembly again implant into body pulp cavity to obtain initial implantation stability.But this technology for the structural design of the knee joint tibia support prosthese wing be design symmetry and the layout of interior lateral condyle; Yet due in knee sprung process, kneed shin femoral joint is mainly in interior side contacts interaction, larger compressive stress and shearing force will be born compared with outside in inner side; Therefore, in above design adopts, the tibia support of lateral condyle design symmetry goes to support asymmetric stress, thereby more easily produces the even destruction of prosthese of becoming flexible, wear and tear due to stressed asymmetric produced prosthese and osseous tissue interface.

Utility model content

This utility model is for prior art above shortcomings, a kind of knee joint tibia support of unsymmetric structure is proposed, according to the stressed unsymmetry of lateral condyle in knee joint, design the tibia support prosthese of asymmetric wing structure, can solve compressive stress and the shearing force of due to outside in knee joint, bearing uneven, the instability problems such as become flexible at the artificial knee joint interface of causing, excessive wear.

This utility model is achieved through the following technical solutions, and this utility model comprises: connected unit, insertosome and be arranged on connected unit and insertosome between girth member, wherein: connected unit is fixedly connected with insertosome.

Described girth member comprises: at least two the first stiffening pieces and at least one second stiffening piece, and wherein, two the first stiffening pieces are vertical with connected unit and crossing with insertosome, and two the first stiffening pieces are positioned at same plane; The end face of the second stiffening piece is positioned in the plane at the first stiffening piece place, and with its formation angle.

Described the first stiffening piece and the angle between the second stiffening piece are 36 °.

Described connected unit and insertosome by welding, spiro connection structure is connected or one-body molded making.

Beneficial effect

Compared with prior art, the knee joint tibia support of unsymmetric structure of the present utility model has added the structure of girth member, the caused by relative motion compressive stress and the shearing force that make the knee joint tibia support of unsymmetric structure can bear better femur and the tibia of human body, be more conducive to and osseous tissue ankylose simultaneously, improve kneed interface stability.

Accompanying drawing explanation

Fig. 1 is structural representation of the present utility model;

Fig. 2 is face upwarding assumption diagram of the present utility model;

Wherein: 1 connected unit, 2 insertosomes, 3 girth members, 31 first stiffening pieces, 32 second stiffening pieces.

Fig. 3 is contact stress and the distribution schematic diagram on tibia polyethylene prosthese when 30-60-90-120 flexing;

In figure: (a) contact stress and the distribution of the contact stress of the contact stress of 30 degree flexings and distribution (b) 60 degree flexings and the contact stress of distribution (c) 90 degree flexings and distribution (d) 120 degree flexings.

Fig. 4 is wearing and tearing and the pictorial diagram of breaking that artificial knee joint tibial prosthesis produces due to high contact stress in inner side.

The specific embodiment

Below embodiment of the present utility model is elaborated; the present embodiment is implemented take technical solutions of the utility model under prerequisite; provided detailed embodiment and concrete operating process, but protection domain of the present utility model is not limited to following embodiment.

Embodiment 1

As shown in Figure 1, 2, this utility model comprises: connected unit 1, insertosome 2 and be arranged on connected unit 1 and insertosome 2 between girth member 3, wherein: connected unit 1 is fixedly connected with insertosome 2.

Described insertosome 2 is plugged in tibia, and the knee joint tibia support by unsymmetric structure couples together tibia and femur.

Described girth member 3 comprises: at least two first stiffening pieces 31 and at least one second stiffening piece 32, and wherein, two the first stiffening pieces 31 are vertical with connected unit 1 and crossing with insertosome 2, and two the first stiffening pieces are positioned at same plane; The end face of the second stiffening piece 32 is positioned in the plane at the first stiffening piece place, and with its formation angle.Described girth member 3 for strengthen insertosome 2 and connected unit 1 intensity, be conducive to the ankylose with human tibia osseous tissue simultaneously, in the present embodiment, described girth member 3 is comprised of two the first stiffening pieces 31 and second stiffening piece 32, during concrete use, can be according to the difference of the structure size of the tibia of human body, described girth member 3 can comprise a plurality of the first stiffening pieces 31 and a plurality of the second stiffening piece 32.

The first described stiffening piece 31 and the angle between the second stiffening piece 32 are 36 °, and the angle of the first stiffening piece 31 and the second stiffening piece 32 also can change as the case may be.

The second stiffening piece 32 of unsymmetric structure is the result of study according to biomechanics, comply with the kneed motion of human body natural and mechanics functional design, therefore, it will bear caused by relative motion compressive stress and the shearing force of the kneed femur of human body and tibia better, be more conducive to and osseous tissue ankylose simultaneously, improve kneed interface stability.

Described connected unit 1 is connected by welding method with insertosome 2.

Described connected unit 1 is connected by spiro connection structure with insertosome 2, more preferably one-body molded making.

As shown in Figure 3, be the finite element analysis result for artificial knee joint prosthesis, contact stress and the distribution on tibia polyethylene prosthese during flexing while being respectively 30 °-60 °-90 °-120 °.By the contact of lateral condyle in observation and comparison, can find to reach in more than 80 ° flexing processes at knee sprung, owing to following the femur inward turning that occurs about 15 ° simultaneously, cause the prosthese of femur and tibial prosthesis when flexing is more than 80 °, at condylus lateralis femoris, do not contact generation.Now, the interaction of knee joint shin femoral joint prosthese causes tibial plateau outward turning.Therefore, soft tissue tension obviously declines inside rear, and outside soft tissue tension improves, and directly causes the contact of lateral condyle in articulatio femorotibialis asymmetric.In inner side, produce larger contact stress and concentrate, when knee sprung reaches 120 °, at the interior posterior lateral margin place of tibial plateau, higher peak value contact stress occurs, reach femur and tibial prosthesis at the maximum of condyle portion contact stress, 21.71Mpa.Simultaneously between articulatio femorotibialis, belong to high-molecular polythene and cobalt chrome molybdenum Metal Contact interface, this stress concentration be the wearing and tearing of high-molecular polythene prosthese rear and the early stage loosening main cause of prosthese.Now, the posterior lateral margin of femoral prosthesis approaches posterior lateral margin place with medial side of tibial plateau condyle rear portion and contacts, and because contact area sharply reduces, directly causes relatively high contact stress.As can be seen from Figure 4, in inner side this region because serious wear out failure appears in the effect of high contact stress.

Claims

1. a knee joint tibia support for unsymmetric structure, is characterized in that, comprising: connected unit, insertosome and be arranged on connected unit and insertosome between girth member, wherein: connected unit is fixedly connected with insertosome.

2. the knee joint tibia support of unsymmetric structure according to claim 1, it is characterized in that, described girth member comprises: at least two the first stiffening pieces and at least one second stiffening piece, wherein: two the first stiffening pieces are vertical with connected unit and crossing with insertosome, and two the first stiffening pieces are positioned at same plane; The end face of the second stiffening piece is positioned in the plane at the first stiffening piece place, and with its formation angle.

3. the knee joint tibia support of unsymmetric structure according to claim 2, is characterized in that, described the first stiffening piece and the angle between the second stiffening piece are 36 °.

4. the knee joint tibia support of unsymmetric structure according to claim 1, is characterized in that, described connected unit and insertosome by welding, spiro connection structure is connected or one-body molded making.