WO2020130986A1

WO2020130986A1 - Ankle prosthesis

Info

Publication number: WO2020130986A1
Application number: PCT/TR2019/051089
Authority: WO
Inventors: Hasan Havitçioğlu; Ömer BEKÇİOĞLU; Bora Uzun; Çağrı HAVITÇIOĞLU; Özgür ŞAMPİYON
Original assignee: Dokuz Eylül Üni̇versi̇tesi̇ Rektörlüğü
Priority date: 2018-12-18
Filing date: 2019-12-16
Publication date: 2020-06-25
Also published as: TR201819753A2

Abstract

The invention is an ankle prosthesis (1) to be applied on the patients with ankle joint damage, in a manner such that the ankle joint motion ratio is closer to the normal ankle functions, characterized in that it comprises the following; a tibial stem (10) which has a component intersection region (14) which enables its engagement with the tibial component (20) by means of being fitted on the stem stabilization groove (21) at its bottom surface, a tibial component (20) which has a stem stabilization groove (21) on which component intersection region (14) in said tibial stem (10) is fitted, a ball (23) which is fitted on the ball bearing (44) in the talar component (40) on the bottom surface on said tibial component (20) and enables front-rear linear motion within the ball bearing (44), an insert (30) having a ball motion gap (36) which consists of a region restricted by an anterior ball motion groove (33) and a posterior ball motion groove (34) wherein the ball (23) in the tibial component (20) can be able to move, talar component housing channels (35) which enable connection between insert (30) and talar component (40) by means of fitting on the insert talar component channels (45) which are disposed on the talar component (40) at the bottom portion of said insert (30), a talar component (40) having a ball bearing (44) on which a ball (23) disposed on the bottom portion of the tibial component (20) can perform front-rear linear motion on its upper surface, on the upper surface of said talar component (40), insert talar component channels (45) which are fitted on the talar component housing channels (35) disposed on the lower portion of the insert (30) side surface (37).

Description

ANKLE PROSTHESIS

Technological Field:

The invention is related to novel ankle prosthesis to be applied on the patients with ankle joint damage, in a manner such that the ankle joint motion ratio is closer to the normal ankle functions. The invention is related to novel ankle prosthesis which is more appropriate to the anatomic features of talus and tibia, allows for a better fixation, is more appropriate to the ankle mechanic and kinematic.

State of the Art:

Total ankle prosthesis application is experienced for the first time in the beginning of 1970’s; however due to insufficient early period a result, the application of this method is left after a period of time. This ankle prosthesis which is known as the first generation was implanted by Lord and Marotte. This design comprises a tibial component having a long body similar to the femoral component of the total knee prosthesis. The talar component consists of a polyethylene part comprising substantially most part of talus. At the end of 10 years, success is obtained in only 7 patients among 25 patients and 12 implants were damaged.

New Jersey cylindrical prosthesis was designed in the year 1976 as a two-part prosthesis consisting of a metal tibial component and talar component with polyethylene tower. Coherent spherical surfaces create a contact area of 5,2 cm2. The prosthesis allows for 65-degree motion ratio as 20 degrees dorsiflexion and 45 degrees plantar flexion. This design was reviewed later and converted into Buechel Pappas design which is still used today. Many clinical results belong to the first generation designs suggest using total ankle prosthesis. In general, due to high complication ratios and damage of total ankle prosthesis implantations, they are proposed to be used in older patients who have only limited physical demands. However great experiences are obtained from the first period designs. First of all it is understood that, using bone cement requires larger amounts of bone resection, thus leads to collapse in the metal component. It is acknowledged that a balance between obtaining stability of the prosthesis and a larger motion ratio shall be established. Slackening of the prosthesis clinically, leads to complications such as continuous pain, delay in wound healing.

Subsequently the second generation ankle prosthesis applications began to be used as of the ends of 1980’s. The ankle prostheses which are designed by considering the natural anatomy and biomechanical conditions of the ankle leads to promising results and thus usage of ankle prosthesis becomes widespread. According to walking and electromyography results, in the patients who are subject to second generation ankle prosthesis applications, it is seen that motion ratio of their daily life activities is within normal limits however their motion ratios in various phases of walking are abnormal.

Together with the widespread usage of the second generation, cementless, minimal limited, three-part implants, prosthesis usage in individuals with ankle joint damage is started to be accepted as an ideal treatment method. Second generation ankle prosthesis are: Star, Hintegra, Salto, Buechel-Pappas, Mobility and Box prostheses.

Today third generation cementless, limitless, mobile bearing ankle prostheses are used in a widespread manner. Many complications are eliminated by means of these designs. The reasons of success of these designs are as follows: a) Proper patient selection

b) Knowledge about biomechanics of the ankle c) usage of less limited designs with less bone resection

d) importance of soft tissue balance and compatibility of the components constituting the prosthesis

e) biocompatibility of the ankle prostheses

In general when we consider the results, it is understood that a design that minimizes the soft tissue damage during surgical application is required. The most important experience concerning the previous designs is related to the polyethylene components used. The joint surfaces which are not in mutual harmony allows for dorsiflexion/plantar flexion and axial rotation however these motions lead to high local tensions which cause too much abrasion on the polyethylene component. For this reason, for more stability and abrasion strength, it is mentioned that designs having surfaces with mutual harmony are required.

Due to the soft tissue limitation exists in the ankle, the problems in the fixation of talus, a novel ankle prosthesis design which considers the insufficiency of the ankle mechanics and kinematics is performed. For this reason, lesser bone resection and better talus fixation are included within the system. In addition to these the movability and the limits of the system are provided in a controlled manner.

In many of the finite element models, while biomechanics of the ankle is formed, loads and limit conditions are simplified. Although some finite element studies are available, in any of them the bone structure, ligaments, fascia and soft tissue components that belong to the foot-ankle complex are found all together.

In the literature research made, United States patent document No US 2014/0135939 is encountered, in which, 3 fixations are used to the talus fixation and the polyethylene is disposed within a bearing. In tibial component it is seen that fixation is performed by means of only one stem at the central portion. In another literature research made, United States patent document No US 9,610,168 B2 is encountered, in which, 3 stems are used for the fixation to the talus together with 3 fixations with 45 degree angle in tibia. In another literature research made, United States patent document No US 2017143500 is encountered, in which, 5 protrusions with different sizes are used for the tibial fixation.

In another literature research made, Australia patent document No AU 2016202925 is encountered, in which, there are fastening holes from the front and side portions in fixation of the talus and also talus is designed in a manner such that screw can be placed laterally.

In another literature research made, United States patent document No US 2017056191 is encountered, in which, there are 3 holes for the fixation of the tibial component.

In another literature research made, United States patent document No US 2017/0216042 A1 is encountered, in which, the system has a structure which can be secured to the talus and calcaneus. There is a structure which comprises the calcaneus base.

In another literature research made, United States patent document No US 2016/0213490 A1 is encountered, in which, the screws placed to the talar component fixes talus and calcaneus, on the other hand the tibial component stem is fixed intramedullary to the tibia.

In another literature research made, United States patent document No US 2004/0122523 A1 is encountered, in which, the tibial component is designed appropriate to the anatomic structure however talar component has a stem with a funnel shape. In another literature research made, United States patent document No US 4069518A is encountered, in which, tibial and talar component has an interlocking stem less structure. In addition to this there are channels on the tibial component which provide stability.

In another literature research made, United States patent document No

US3987500A is encountered, in which, the tibial component stem has a square form. In another literature research made, United States patent document No

US3872519A is encountered, in which, it comprises a multi-layered pyramid formed tibial component.

Consequently novel ankle prosthesis is required in which the present state of the art is exceeded, the disadvantages are eliminated.

Brief Description of the Invention:

The invention is a novel ankle prosthesis in which the present state of the art is exceeded, the disadvantages are eliminated and additional features are included.

The aim of the invention is to represent the ankle joint as much closer as possible. Particularly, it aims to provide an ankle prosthesis which has an appropriate motion range in a manner such that it allows for walking phases and other daily activities.

Another aim of the invention is to provide an ankle prosthesis which can be used in total ankle change, in repeating surgical technique, has features of minimal bone resection, fast and sufficient bone growth, minimal limiting and continuation of physiological ankle motions and pain killing. Another aim of the invention is to provide an ankle prosthesis which has a design that would minimize the complications and early revision requirement in long term. Another aim of the invention is to enable the contact area between the prosthesis components dispersing the load in a balanced manner and is appropriate for preventing the contact forces.

The present invention in order to realize all aims occurred due to the abovementioned and below described detailed description, is an ankle prosthesis to be applied on the patients with ankle joint damage, in a manner such that the ankle joint motion ratio is closer to the normal ankle functions, characterized in that it comprises the following; a tibial stem which has a component intersection region which enables its engagement with the tibial component by means of being fitted on the stem stabilization groove at its bottom surface, a tibial component which has a stem stabilization groove on which component intersection region in the tibial stem is fitted, a ball which is fitted on the ball bearing in the talar component on the bottom surface on said tibial component and enables front-rear linear motion within the ball bearing, an insert having a ball motion gap which consists of a region restricted by an anterior ball motion groove and a posterior ball motion groove wherein the ball in the tibial component can be able to move, talar component housing channels which enable connection between insert and talar component by means of fitting on the insert talar component channels which are disposed on the talar component at the bottom portion of said insert, a talar component having a ball bearing on which a ball disposed on the bottom portion of the tibial component can perform front-rear linear motion on its upper surface, on the upper surface of said talar component, insert talar component channels which are fitted on the talar component housing channels disposed on the lower portion of the insert side surface. Another preferred embodiment of the invention is characterized in that; all surfaces of the tibial stem are coated surfaces manufactured from bio-material in order to provide biocompatibility. Another preferred embodiment of the invention is characterized in that; it comprises a rear end and an inclined front end on the tibial stem in order to provide anatomic compatibility.

Another preferred embodiment of the invention is characterized in that; it comprises tibial fixation screw holes on the tibial component which enables fixation with the foot tibial section.

Another preferred embodiment of the invention is characterized in that; it comprises ball side surfaces which enables linear front rear motion of the ball by means of limiting the lateral movements of the ball within the ball bearing.

Another preferred embodiment of the invention is characterized in that; it comprises a ball stem which enables connection of the ball with the bottom portion of the tibial component.

Another preferred embodiment of the invention is characterized in that; insert comprises an insert wide anterior region and an insert narrow anterior region which are configured according to the anatomic structure. Another preferred embodiment of the invention is characterized in that; talar component comprises a talar component wide anterior region and a talar component narrow anterior region which are configured according to the anatomic stricture. Another preferred embodiment of the invention is characterized in that; it comprises talar fixation screw holes on the talar component which enables fixation with the foot talar region. Description of Figures:

The invention will now be described with reference to the attached drawings, thus the features of the invention will be clearly understood. Flowever, the aim of this is not limiting the invention with particular embodiments. On the contrary it is aimed to cover all alternatives, amendments and equivalents that would include the field of the invention described in the attached claims. It is to be understood that the details shown are illustrated for the sake of only clarifying the preferred embodiments of the present invention and forming the methods, and also for providing the most useful and apparent description of the rules of the invention and conceptual features. In these drawings;

Figure - 1 is a perspective view of the inventive ankle prosthesis.

Figure - 2 is a perspective view of the tibial stem included in the inventive ankle prosthesis.

Figure - 3A is a top view of the tibial component included in the inventive ankle prosthesis.

Figure - 3B is a side view of the tibial component included in the inventive ankle prosthesis.

Figure - 3C is a front view of the tibial component included in the inventive ankle prosthesis.

Figure - 3D is a perspective view of the tibial component included in the inventive ankle prosthesis.

Figure - 4A is a top view of the insert included in the inventive ankle prosthesis.

Figure - 4B is a perspective view of the insert included in the inventive ankle prosthesis.

Figure - 5A is a top view of the talar component included in the inventive ankle prosthesis.

Figure - 5B is a perspective view of the talar component included in the inventive ankle prosthesis. The figures clarifying this invention are enumerated as shown in the attached drawing and they are given with their names herein below.

Description of the References:

I. Ankle prosthesis

10.Tibial stem

I I. Coated surface

12. Rear end

13. inclined front end

14. Component intersection region

20.Tibial component

21. Stem stabilization groove

22.Tibial fixation screw hole

23. Ball

24. Ball side surface

25. Ball stem

30. Insert

31. Insert wide anterior region

32. Insert narrow posterior region

33.Anterior ball motion groove

34. Posterior ball motion groove

35.Talar component housing channel

36. Ball motion gap

37. Insert side surface

40.Talar component

41. Talar component wide anterior region

42.Talar component narrow posterior region 43.Talar fixation screw hole

44. Ball bearing

45. Insert talar component channel

Description of the Invention:

In this detailed description, the inventive ankle prosthesis (1 ) is only described for clarifying the subject matter in non-limiting manner. In the description, ankle prosthesis (1 ) to be applied on the patients with ankle joint damage, in a manner such that the ankle joint motion ratio is closer to the normal ankle functions is disclosed.

In Figure 1 , a perspective view of the inventive ankle prosthesis (1 ) is given. Accordingly, it consists of four main parts as the ankle prosthesis (1 ), tibial stem (10), tibial component (20), insert (30) and talar component (40).

In Figure 2, a view showing the tibial stem (10) of the inventive ankle prosthesis (1 ) is given. Accordingly, on the stem (10); there is a rear end (12), an inclined front end (13), a component intersection region (14) which enables connection of the stem (10) with the tibial component (20). The surface of the tibial stem (10) consists of a coated surface (11 ) in order to provide bio-compatibility.

In Figure 3A, a top view showing the tibial component (20) portion of the inventive ankle prosthesis (1 ) is given. Accordingly, there is a stem stabilization groove (21 ) on the upper surface of the tibial component (20) for placing the tibial stem (10) and tibial fixation screw holes (22) which enable the tibial fixation of the prosthesis (1 ). In Figures 3B and 3C, side and front views of the tibial component (20) are given. Accordingly, there is a ball (23) on the lower portion of the tibial component (20). In the Figures, the ball side surfaces (24) are seen. Since the ball side surfaces (24) are flat, front-rear linear motion of the ball (23) fitted on the talar component (40) ball bearing (44) is enabled. In Figure 3D, the view of the ball (23) attached on the bottom portion of the tibial component (20) by means of a ball stem (25) can be seen in a clear manner.

In Figure 4A, top view of the insert (30) element of the inventive ankle prosthesis (1 ) is given. Accordingly, insert (30) comprises a ball motion gap (36) which consists of anterior ball motion groove (33) and posterior ball motion groove (33), in which the tibial component balls (23) moves. The insert (30) body consists of the insert wide anterior region (31 ), insert narrow posterior region (32), and insert side surfaces (37). In Figure 4B, a top view of the insert (30) element of the inventive ankle prosthesis (1 ) is given. Accordingly, there are talar component housing channels (35) which enable connection with the talar component (40) at the bottom portion of two side surfaces (37) of the insert (30). In Figure 5A, a top view showing the talar component (40) element of the inventive ankle prosthesis (1 ) is given. Accordingly, talar component (40) body consists of the talar component wide anterior region (41 ), talar component narrow posterior region (42) and side surfaces. On the talar component (40); there are talar fixation screw holes (43) which enable talar fixation. Also in the middle of the talar component (40), there is ball bearing (44) wherein the ball (23) disposed on the tibial component (20) moves. The ball (23) can perform its linear front-rear motion (natural ankle motion) within the ball bearing (44). In Figure 5B, a perspective view of the talar component (40) of the inventive ankle prosthesis (1 ). Accordingly, on two side sections of the talar component (40), there are insert talar component channels (45) which enables connection between the insert (30) and talar component (40) by means of fitting on the talar component housing channels (35) on the insert (30).

In the invention, first of all the insert (30) is engaged with the talar component (40) by means of being fitted on the insert talar component channels (45) through the housing channels (35) disposed on the lower portion of the side surface (37). Subsequently, the tibial component (20) is fitted on the ball bearing (44) disposed in the talar component (40) by means of the ball (23) disposed thereon. Finally, the tibial stem (10) is fitted on the stem stabilization groove (21 ) on the tibial component (20) through its intersection region (14) and thus the assembly is completed. As it can be understood, the design and assembly of the parts constituting the ankle prosthesis (1 ) is not complex.

Claims

1- The invention is an ankle prosthesis (1 ) to be applied on the patients with ankle joint damage, in a manner such that the ankle joint motion ratio is closer to the normal ankle functions, characterized in that; it comprises the following;

- a tibial stem (10) which has a component intersection region (14) which enables its engagement with the tibial component (20) by means of being fitted on the stem stabilization groove (21 ) at its bottom surface,

- a tibial component (20) which has a stem stabilization groove (21 ) on which component intersection region (14) in said tibial stem (10) is fitted,

- a ball (23) which is fitted on the ball bearing (44) in the talar component (40) on the bottom surface on said tibial component (20) and enables front-rear linear motion within the ball bearing (44),

- an insert (30) having a ball motion gap (36) which consists of a region restricted by an anterior ball motion groove (33) and a posterior ball motion groove (34) wherein the ball (23) in the tibial component (20) can be able to move,

- talar component housing channels (35) which enable connection between insert (30) and talar component (40) by means of fitting on the insert talar component channels (45) which are disposed on the talar component (40) at the bottom portion of said insert (30),

- a talar component (40) having a ball bearing (44) on which a ball (23) disposed on the bottom portion of the tibial component (20) can perform front-rear linear motion on its upper surface.

- on the upper surface of said talar component (40), insert talar component channels (45) which are fitted on the talar component housing channels (35) disposed on the lower portion of the insert (30) side surface (37).

2- An ankle prosthesis (1 ) according to claim 1 , characterized in that; all surfaces of the tibial stem (10) are coated surfaces (11 ) manufactured from bio material in order to provide biocompatibility. 3- An ankle prosthesis (1 ) according to claim 1 , characterized in that; it comprises a rear end (12) and an inclined front end (13) on the tibial stem (10) in order to provide anatomic compatibility. 4- An ankle prosthesis (1 ) according to claim 1 , characterized in that; it comprises tibial fixation screw holes (22) on the tibial component (20) which enables fixation with the foot tibial section.

5- An ankle prosthesis (1 ) according to claim 1 , characterized in that; it comprises ball side surfaces (24) which enables linear front rear motion of the ball (23) by means of limiting the lateral movements thereof within the ball bearing (44).

6- An ankle prosthesis (1 ) according to claim 1 , characterized in that; it comprises a ball stem (25) which enables connection of the ball (23) with the bottom portion of the tibial component (20).

7- An ankle prosthesis (1 ) according to claim 1 , characterized in that; insert (30) comprises an insert wide anterior region (31 ) and an insert narrow anterior region (32) which are configured according to the anatomic structure.

8- An ankle prosthesis (1 ) according to claim 1 , characterized in that; talar component (40) comprises a talar component wide anterior region (41 ) and a talar component narrow anterior region (42) which are configured according to the anatomic stricture.

9- An ankle prosthesis (1 ) according to claim 1 , characterized in that; it comprises talar fixation screw holes (43) on the talar component (40) which enables fixation with the foot talar region.