A special internal fixation device for proximal tibial combined osteotomy

Abstract

The present invention relates to a special internal fixation device for proximal tibial combined osteotomy, including a support plate and a plurality of locking screws. The support plate is composed of a proximal head, an intermediate connecting part and a distal tail which are sequentially connected and integrally formed. Locking screw holes are respectively provided on the proximal head and the distal tail. A locking / pressurizing combination hole is also provided on the intermediate connecting part. The locking screws are respectively and correspondingly inserted into the locking screw holes and the locking / pressurizing combination holes. The locking screw holes on the proximal head include a first screw hole, a second screw hole and a third screw hole which are arranged horizontally, and an additional screw hole located at the lower corner position of the proximal head. The installation angle of the additional screw hole satisfies that the direction of the locking screw inserted into the additional screw hole is perpendicular to the osteotomy surface at the intercondylar eminence of the tibia. The present invention can provide a more stable knee joint biomechanical environment for the treatment of varus knee osteoarthritis by proximal tibial combined osteotomy, and is more firm and reliable than the existing plate internal fixation.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices and relates to a special internal fixation device for proximal tibial combined osteotomy. Background Art

[0002] Knee osteoarthritis is a common chronic joint disease in knee joint surgery, with a high prevalence rate, a wide range of lesions, and a severe degree of late functional impairment. The most common type of knee osteoarthritis is knee varus deformity, also known as "O-shaped legs", which refers to a deformity disease in which the inner ankles of both feet can touch while the knees cannot close when the two lower limbs are naturally straightened or standing, and is formed by the combined action of two pathological factors outside and inside the joint. Open wedge high tibial osteotomy (OWHTO) is a commonly used method for treating varus knee osteoarthritis, mainly for correcting extra-articular deformities, with strong ability to correct the mechanical axis, but there is still residual intra-articular deformity after surgery. Tibial condylar osteotomy (TCVO) mainly corrects intra-articular deformities, but has a weak ability to correct the mechanical axis and is less commonly used clinically, and its stability lacks basic biomechanical research. Therefore, proximal tibial combined osteotomy (CPTO) has been newly proposed, which is based on the traditional high tibial osteotomy (OWHTO) and adopts a surgical method similar to TCVO at the proximal tibial condyle, and at the same time performs intra-articular osteotomy, which can correct both intra-articular and extra-articular deformities of varus knee arthritis.

[0003] Currently, the Tomofix internal fixation system and additional screws are used for fixation in CPTO surgery, but it is difficult to determine the exact position and direction of the implantation of the additional screws, and there are problems of insufficient structural stability and inconvenient surgical operation. Therefore, there is an urgent need for an internal fixation orthopedic plate system specifically applied to CPTO surgery. Summary of the Invention

[0004] The purpose of the present invention is to provide a special internal fixation device for proximal tibial combined osteotomy, which is more firm and reliable than the existing plate internal fixation.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A special internal fixation device for proximal tibial combined osteotomy, comprising a support plate and a number of locking screws. The support plate consists of a proximal head, an intermediate connecting part and a distal tail which are connected in sequence and integrally formed. The proximal head fits against the anterior medial surface of the proximal tibial plateau, and the distal tail fits against the anterior medial surface of the tibial shaft. Locking screw holes are respectively provided on the proximal head and the distal tail, and a locking / pressurizing combination hole is also provided on the intermediate connecting part. The locking screws are respectively and correspondingly inserted into the locking screw holes and the locking / pressurizing combination holes. Among them, the locking screw holes on the proximal head include a first screw hole, a second screw hole and a third screw hole arranged horizontally, and an additional screw hole located at the lower corner position of the proximal head. The installation angle of the additional screw hole satisfies that the direction of the locking screw inserted into the additional screw hole is perpendicular to the osteotomy surface at the intercondylar eminence of the tibia.

[0007] Further, the locking screws corresponding to the first screw hole, the second screw hole and the third screw hole are respectively a first screw, a second screw and a third screw. And the direction of the second screw inserted into the second screw hole is in the same plane as the normal line passing through the center of the second screw hole of the proximal head and the included angle with the normal line is 14-16°. The insertion directions of the first screw and the third screw are both in the same plane as the second screw.

[0008] Furthermore, the included angles between the connecting lines of the first screw, the third screw and the second screw are respectively 80-85°.

[0009] Further, the surface curvature of the proximal head is consistent with the surface curvature of the anterior medial surface of the proximal tibia.

[0010] Further, the edge of the outer surface of the proximal head is in a smooth arc shape.

[0011] Further, the directions of the locking screws inserted into the locking / pressurizing combination holes are all perpendicular to the axis of the tibial shaft.

[0012] Further, there are three locking / pressurizing combination holes, one of which is located on the side of the proximal head close to the transverse osteotomy surface of the tibia, and the other two are located on the side of the distal tail close to the transverse osteotomy surface of the tibia.

[0013] Further, the locking / pressurizing combination hole is formed by connecting a locking threaded hole and a smooth inner surface pressurizing round hole, and is in a "gourd shape".

[0014] Further, the locking screw consists of a screw head in an inverted conical shape integrally formed and a screw rod part. Among them, the outer wall surface of the screw head is provided with a first thread matching the locking screw hole, and the outer wall surface of the screw rod part is also provided with a second thread.

[0015] Furthermore, the pitch of the second thread is greater than the pitch of the first thread.

[0016] Further, the end of the screw rod portion is conical.

[0017] Further, the end of the distal tail portion is fusiform.

[0018] Compared with the prior art, the special internal fixation device for proximal tibial combined osteotomy provided by the present invention adds the connection and fixation of the medial wedge of the tibial plateau by setting a locking screw hole with a fixed angle at the corner of the main plate of the steel plate. Under the combined support of the proximal locking screw and the additional locking screw, the medial and lateral parts of the proximal tibial plateau are re-integrated into a complete platform, providing a more stable biomechanical environment for the knee joint, and being more firm and reliable than the existing steel plate internal fixation. Description of the Drawings

[0019] Figure 1 Schematic view of the front inner side perspective of the special internal fixation device of the present invention combined with the tibia;

[0020] Figure 2 Schematic view of the front perspective of the special internal fixation device of the present invention combined with the tibia;

[0021] Figure 3 Schematic view of the side perspective of the special internal fixation device of the present invention;

[0022] Figure 4 Front view structural schematic diagram of the support steel plate of the present invention;

[0023] Figure 5 Top view perspective structural schematic diagram of the support steel plate of the present invention;

[0024] Figure 6 Structural schematic diagram of the locking screw of the present invention;

[0025] Figure 7 Simulation nephogram obtained by finite element analysis;

[0026] Explanation of the marks in the figures:

[0027] 1 - Support steel plate, 101 - Proximal head, 102 - Intermediate connecting portion, 103 - Distal tail;

[0028] 2 - Locking screw hole, 201 - First screw hole, 202 - Second screw hole, 203 - Third screw hole, 204 - Additional screw hole, 205 - Fourth screw hole;

[0029] 3 - Locking / pressurizing combination hole;

[0030] 4 - Locking screw, 401 - First screw, 402 - Second screw, 403 - Third screw, 404 - Additional screw, 411 - Screw head, 412 - Screw shank, 413 - Screw end, 421 - First thread, 422 - Second thread. Detailed implementation mode

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives the detailed implementation mode and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0032] In the following embodiments or examples, if there is no special description of the functional components or structures, it means that they are all conventional components or conventional structures adopted in the art to achieve the corresponding functions.

[0033] To be used in conjunction with the proximal tibial combined osteotomy to improve the firmness, reliability and operation convenience of its internal fixation, the present invention provides a special internal fixation device for proximal tibial combined osteotomy, and its structure is shown in Figures 1 to 3 As shown, it includes a support plate 1 and a plurality of locking screws 4. The support plate 1 is composed of a proximal head 101, an intermediate connecting portion 102 and a distal tail 103 which are sequentially connected and integrally formed. The proximal head 101 fits on the anterior medial surface of the proximal tibial plateau, and the distal tail 103 fits on the anterior medial surface of the tibial shaft. Locking screw holes 2 are respectively provided on the proximal head 101 and the distal tail 103, and a locking / pressurizing combination hole 3 is also provided on the intermediate connecting portion 102. The locking screws 4 are respectively arranged in the locking screw holes 2 and the locking / pressurizing combination hole 3. Among them, the locking screw holes 2 on the proximal head 101 include a first screw hole 201, a second screw hole 202 and a third screw hole 203 arranged horizontally, and an additional screw hole 204 located at the lower corner position of the proximal head 101. The installation angle of the additional screw hole 204 satisfies that the direction of the locking screw 4 placed in the additional screw hole 204 is perpendicular to the osteotomy surface at the intercondylar eminence of the tibia. At the same time, the length of the additional screw 404 placed in the additional screw hole 204 satisfies that it passes through the bone osteotomy surface and connects the inner and outer wedge-shaped bone blocks longitudinally cut open at the proximal tibia, so as to realize the connection fixation and support of the medial tibial wedge.

[0034] In some specific implementation modes, please refer to Figure 1As shown in etc., the locking screws 4 corresponding to the first screw hole 201, the second screw hole 202 and the third screw hole 203 are respectively the first screw 401, the second screw 402 and the third screw 403. And the direction in which the second screw 402 is inserted into the second screw hole 202 is in the same plane as the normal line passing through the center of the second screw hole 202 of the proximal head 101 and the included angle with this normal line is 14 - 16°. The insertion directions of the first screw 401 and the third screw 403 are both in the same plane as the second screw 402.

[0035] In a more specific embodiment, the included angles between the connecting lines of the first screw 401, the third screw 403 and the second screw 402 are respectively 80 - 85°, which can be adjusted individually based on the patient's condition, enhancing the supporting effect on the tibial plateau.

[0036] In some specific embodiments, please refer to again Figure 5 As shown in etc., the surface curvature of the proximal head 101 is consistent with the surface curvature of the anteromedial side of the proximal tibia, ensuring a tight fit between the plate head and the tibia. At the same time, the edge of the outer surface of the proximal head 101 is in a smooth arc shape, which can avoid scratching human tissues and reduce soft tissue irritation.

[0037] In some specific embodiments, please refer to again Figure 3 As shown in etc., the directions of the locking screws 4 inserted into the corresponding locking / compression combination holes 3 are all perpendicular to the axis of the tibial shaft, improving the fixation effect on the tibial shaft.

[0038] In some specific embodiments, please refer to again Figure 1 As shown in etc., there are three locking / compression combination holes 3, one of which is located on the side of the tibial transverse osteotomy surface close to the proximal head 101, and the other two are located on the side of the tibial transverse osteotomy surface close to the distal tail 103.

[0039] In some specific embodiments, please refer to again Figure 4 As shown in etc., the locking / compression combination hole 3 is formed by connecting a locking threaded hole and a smooth compression round hole on the inner surface, and is in a "gourd shape". The locking threaded hole and the smooth compression round hole respectively correspond to the locking screw and the ordinary tension screw. The locking screw is used to increase the connection stability, and the ordinary tension screw is used for compression. The locking screw or the ordinary tension screw can be selected according to the surgical needs.

[0040] In some specific embodiments, please refer to again Figure 6As shown in the figure, the locking screw 4 is composed of a screw head 411 with an inverted conical shape formed integrally and a screw rod portion 412. Among them, the outer wall surface of the screw head 411 is provided with a first thread 421 that matches the locking screw hole 2, and the outer wall surface of the screw rod portion 412 is also provided with a second thread 422. In addition, the taper of the screw head 411 can be 1:2 to 1:1.5. Through the first thread 421, the screw head 411 can be cooperatively connected with the inner wall of the locking screw hole 2 to form a structure with a fixed angle, providing angular stability. At the same time, the screw head 411 is also embedded in the locking screw hole 2, which can reduce the external leakage area. The screw rod portion has strong bending and shear strength and transmits the load to the bone.

[0041] In a more specific embodiment, the pitch of the second thread 422 is greater than the pitch of the first thread 421. The proximal tibia screw is close to the tibial plateau. The smaller pitch of the first thread can prevent the screw from being driven too much into the joint, ensuring the safety of the use of the internal fixation device.

[0042] In a more specific embodiment, the end of the screw rod portion 412 is conical.

[0043] In some specific embodiments, the end of the distal tail 103 is fusiform, which is convenient for instrument implantation.

[0044] In some specific embodiments, the materials of the support plate 1 and the locking screw 4 are both titanium alloy, which has high strength and good human biocompatibility. At the same time, the length of the support plate 1 can be 100 - 130 mm, the width of the proximal head 101 can be 30 - 39 mm, the thickness is 2.4 - 3.1 mm, and it can accept a locking screw 4 with a diameter of about 4.5 - 5.0 mm. The length of the locking screw 4 is 24 - 75 mm, which is selected according to different body types of patients and meets its corresponding functions.

[0045] The above embodiments can be implemented separately, or any two or more of them can be combined for implementation.

[0046] The following will further illustrate the above embodiments in more detail with specific examples.

[0047] Example 1:

[0048] To cooperate with the use of proximal tibia combined osteotomy and improve the firmness, reliability and operation convenience of its internal fixation, this example provides a special internal fixation device for proximal tibia combined osteotomy, and its structure is shown in Figures 1 to 3As shown in the figure, it includes a support plate 1 and a number of locking screws 4. The support plate 1 is composed of a proximal head 101, an intermediate connecting part 102 and a distal tail 103 which are connected in sequence and integrally formed. The proximal head 101 fits against the anterior medial surface of the proximal tibial plateau, and the distal tail 103 fits against the anterior medial surface of the tibial shaft. Locking screw holes 2 are respectively provided on the proximal head 101 and the distal tail 103, and a locking / pressurizing combination hole 3 is also provided on the intermediate connecting part 102. The locking screws 4 are respectively and correspondingly inserted into the locking screw holes 2 and the locking / pressurizing combination hole 3. Among them, the locking screw holes 2 on the proximal head 101 include a first screw hole 201, a second screw hole 202 and a third screw hole 203 arranged horizontally, and an additional screw hole 204 located at the lower corner position of the proximal head 101. The installation angle of the additional screw hole 204 satisfies that the direction of the locking screw 4 inserted into the additional screw hole 204 is perpendicular to the osteotomy surface at the intercondylar eminence of the tibia. At the same time, the length of the additional screw 404 inserted into the additional screw hole 204 satisfies that it passes through the bone cross-section and connects the internal and external wedge-shaped bone blocks longitudinally cut open at the proximal tibia, realizing the connection, fixation and support of the medial wedge of the tibia. At the same time, two fourth screw holes 205 are also provided at the distal tail 103, and locking screws matching them are inserted.

[0049] Please refer to Figure 1 As shown in the figure, etc., the locking screws 4 corresponding to the first screw hole 201, the second screw hole 202 and the third screw hole 203 are respectively a first screw 401, a second screw 402 and a third screw 403, and the direction of the second screw 402 inserted into the second screw hole 202 is in the same plane as the normal line of the proximal head 101 passing through the center of the second screw hole 402 and the included angle with this normal line is 14 - 16°. The insertion directions of the first screw 401 and the third screw 403 are both in the same plane as the second screw 402. The included angles between the connecting lines of the first screw 401, the third screw 403 and the second screw 402 are respectively 80 - 85°, which can be adjusted individually based on the patient's condition, enhancing the supporting effect on the tibial plateau.

[0050] Please refer to Figure 5 As shown in the figure, etc., the surface curvature of the proximal head 101 is consistent with the surface curvature of the anterior medial surface of the proximal tibia, ensuring a tight fit between the plate head and the tibia. At the same time, the edge of the outer surface of the proximal head 101 is in a smooth arc shape, which can avoid scratching human tissues and reduce soft tissue irritation.

[0051] Please refer to Figure 3 As shown in the figure, etc., the directions of the locking screws 4 correspondingly inserted into the locking / pressurizing combination holes 3 are all perpendicular to the axis of the tibial shaft, improving the fixation effect on the tibial shaft.

[0052] Please refer to Figure 1As shown, there are three locking / compression combination holes 3, one of which is located on the side of the tibial transverse osteotomy surface near the proximal head 101, and the other two are located on the side of the tibial transverse osteotomy surface near the distal tail 103.

[0053] Please refer to Figure 4 As shown, the locking / compression combination hole 3 is formed by connecting a locking threaded hole and a smooth compression round hole on the inner surface, and is in a "gourd shape". The locking threaded hole and the smooth compression round hole respectively correspond to the locking screw and the ordinary tension screw. The locking screw is used to increase the connection stability, and the ordinary tension screw is used for compression. The locking screw or the ordinary tension screw can be selected according to the surgical needs.

[0054] Please refer to Figure 6 As shown, the locking screw 4 is composed of a screw head 411 in an inverted conical shape formed integrally and a screw rod part 412. Among them, the outer wall surface of the screw head 411 is provided with a first thread 421 matching the locking screw hole 2, and the outer wall surface of the screw rod part 412 is also provided with a second thread 422. In addition, the taper of the screw head 411 can be 1:2 to 1:1.5. Through the first thread 421, the screw head 411 can be fitted and connected with the inner wall of the locking screw hole 2 to form a structure with a fixed angle, providing angular stability. At the same time, the screw head 411 is also embedded in the locking screw hole 2, which can reduce the outer leakage area. The screw rod part has strong bending and shear strength and transmits the load to the bone. The pitch of the second thread 422 is greater than the pitch of the first thread 421. The proximal tibial screw is close to the tibial plateau. The smaller pitch of the first thread can prevent the screw from being driven too much into the joint, ensuring the safety of the use of the internal fixation device.

[0055] The end of the screw rod part 412 (i.e., the screw end 413) is conical. The end of the distal tail 103 is fusiform, which is convenient for the implantation of the instrument.

[0056] In this embodiment, the materials of the support plate 1 and the locking screw 4 are both titanium alloy, which has high strength and good human biocompatibility. At the same time, the length of the support plate 1 can be 100 - 130 mm, the width of the proximal head 101 can be 30 - 39 mm, the thickness is 2.4 - 3.1 mm, and it can accept a locking screw 4 with a diameter of about 4.5 - 5.0 mm, while the length of the locking screw 4 is 24 - 75 mm, which is selected according to the different body types of patients and meets its corresponding functions.

[0057] Specifically, a finite element simulation analysis was carried out on the special internal fixation device for proximal tibial combined osteotomy, including the following steps: S1. Establish a postoperative model of proximal tibial combined osteotomy using 3D software; S2. Import the 3D model obtained in step S1 into the finite element simulation software for mesh generation and material property setting; S3. Apply the boundary conditions and loads of the proximal tibial combined osteotomy model for simulation calculation; S4. Calculate the simulation nephogram, observe the stress distribution and structural micro-motion conditions. By quickly modeling the postoperative model of proximal tibial combined osteotomy and conducting simulation analysis, the stress concentration areas are obtained, the stability of the special internal fixation device for proximal tibial combined osteotomy is analyzed, and then the special internal fixation device for proximal tibial combined osteotomy is optimized. The obtained simulation nephogram is as shown in Figure 7 shown. It can be seen from Figure 7 that the stress distribution characteristics of the tibia, plate and screws in the special internal fixation device for proximal tibial combined osteotomy are similar to those of the traditional plate system. The stress is concentrated in the rear part of the plate, the holes around the wedge and the middle area of the screws, indicating that the design of this device is reliable. At the same time, the additional screws bear part of the load of the proximal screws, reducing the risk of proximal screw fracture and improving the stability and success rate of CPTO.

[0058] Generally speaking, for the special internal fixation device for proximal tibial combined osteotomy in this embodiment, a fixed-angle additional screw hole 204 is provided at the plate corner of the support plate 1 to increase the connection and fixation of the medial wedge of the tibial plateau. The medial and lateral parts of the proximal tibial plateau are recombined into a complete platform under the combined support of the three proximal locking screws 4 (i.e., the first screw 401, the second screw 402 and the third screw 403) and the additional screw 404, providing a more stable biomechanical environment for the knee joint and being more firm and reliable than the existing plate internal fixation.

[0059] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. Obviously, those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A special internal fixation device for proximal tibial combined osteotomy, characterized in that, It includes a supporting steel plate and a number of locking screws. The supporting steel plate is composed of a proximal head, an intermediate connecting part and a distal tail which are connected in sequence and integrally formed. The proximal head fits on the anterior inner side surface of the proximal tibial plateau, and the distal tail fits on the anterior inner side surface of the tibial shaft. Locking screw holes are respectively provided on the proximal head and the distal tail, and a locking / pressurizing combination hole is also provided on the intermediate connecting part. The locking screws are respectively and correspondingly inserted into the locking screw holes and the locking / pressurizing combination holes. Among them, the locking screw holes on the proximal head include a first screw hole, a second screw hole and a third screw hole arranged horizontally, and an additional screw hole located at the lower corner position of the proximal head. The installation angle of the additional screw hole satisfies that the direction of the locking screw inserted into the additional screw hole is perpendicular to the osteotomy surface at the intercondylar eminence of the tibia; The length of the additional screw inserted into the additional screw hole satisfies that it passes through the bone osteotomy surface and connects the inner and outer wedge-shaped bone blocks longitudinally cut open at the proximal tibia, realizing the connection, fixation and support of the medial wedge of the tibia; The locking screws corresponding to the first screw hole, the second screw hole and the third screw hole are respectively a first screw, a second screw and a third screw. The direction of the second screw inserted into the second screw hole is in the same plane as the normal line passing through the center of the second screw hole of the proximal head, and the included angle with the normal line is 14-16°. The insertion directions of the first screw and the third screw are both in the same plane as the second screw; the included angles between the connecting lines of the first screw, the third screw and the second screw are respectively 80-85°; There are three locking / pressurizing combination holes, one of which is located on the side of the tibial transverse osteotomy surface close to the proximal head, and the other two are located on the side of the tibial transverse osteotomy surface close to the distal tail; The locking / pressurizing combination hole is formed by connecting a locking threaded hole and a smooth pressurizing round hole with a smooth inner surface, and is in a "gourd shape"; the locking threaded hole and the smooth pressurizing round hole respectively correspond to a locking screw and a common tension screw. The locking screw is used to increase the connection stability, and the common tension screw is used for pressurization. The locking screw or the common tension screw is selected according to the surgical needs; The locking screw is composed of a screw head in an inverted conical shape integrally formed and a screw rod part. Among them, the outer wall surface of the screw head is provided with a first thread matching the locking screw hole, and the outer wall surface of the screw rod part is also provided with a second thread; the taper of the screw head can be 1:2 to 1:1.

5. Through the first thread, the screw head is connected and matched with the inner wall of the locking screw hole to form a structure with a fixed angle, providing angle stability. At the same time, the screw head is also embedded in the locking screw hole to reduce the outer leakage area.

2. The special internal fixation device for proximal tibial combined osteotomy according to claim 1, wherein The surface curvature of the proximal head is consistent with the surface curvature of the anterior inner side surface of the proximal tibia.

3. The special internal fixation device for proximal tibial combined osteotomy according to claim 1, characterized in that, The directions of the locking screws correspondingly inserted into the locking / pressurizing combination holes are all perpendicular to the axis of the tibial shaft.

4. A special internal fixation device for proximal tibial combined osteotomy according to claim 1, characterized in that, The pitch of the second thread is greater than the pitch of the first thread.

5. A special internal fixation device for proximal tibial combined osteotomy according to claim 1, characterized in that, The end of the screw rod part is in a conical shape.

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