Intramedullary axial compression fixation prosthesis for metaphyseal bone defects

Abstract

The present application relates to the technical field of prosthetic reconstruction of adjacent joint bone defects, and in particular to an intramedullary axial pressure fixation prosthesis for metaphyseal bone defects. The key points of its technical solution are: it includes a pressure rod and a fixing member for fixing the position of the pressure rod, the pressure rod extends into a fixing handle, a pressure tail cap threadedly connected to the pressure rod is arranged inside the fixing handle, a nut hole for inserting the pressure tail cap is opened on the fixing handle, the pressure tail cap abuts against the bottom of the nut hole and can rotate inside the nut hole; the purpose of exerting mutual pressure between the prosthesis and the retained bone is achieved, thereby promoting the bone ingrowth effect and making the connection between the two more stable in the early postoperative period.

Description

Technical Field

[0001] The present application relates to the technical field of prosthetic reconstruction of metaphyseal bone defects, and in particular to an intramedullary axial compression fixation prosthesis for metaphyseal bone defects. Background Art

[0002] Bone defects caused by pathological processes, such as comminuted fractures caused by trauma, inflammation, bone diseases, large bone tissue defects caused by open fractures, bone necrosis and separation caused by inflammation, and defects caused by large pieces of bone necrosis caused by bone infarction or ischemic necrosis, etc., all belong to bone defects. Bone defects can be treated by bone grafting, that is, the part of the patient's bone that causes the bone defect is cut off, and the fixed stem of the prosthesis is surgically transplanted to the retained bone in the patient's body and the part that needs to be strengthened or fused. Figure 1 When the fixation handle needs to be fixed on the retained bone, the end face of the fixation handle is brought into contact with the cross section of the retained bone, and a steel plate is simultaneously installed and fixed on one side of the fixation handle and the retained bone to achieve reconstruction.

[0003] With respect to the above-mentioned related technical solutions, the inventors found that: although it is now possible to perform coating treatment on the end face of the fixing handle, the coating includes but is not limited to 3D printed trabecular bone-like porous structure, titanium / tantalum spray coating, hydroxyapatite coating, etc., to promote bone ingrowth and thus achieve long-term fixation, the fixing handle and the retained bone will still have slight displacements from each other during the wound healing process, leading to difficulties in healing and bone ingrowth. If a certain pressure is applied between the end face of the fixing handle and the retained bone cross-section, the end face of the fixing handle and the retained bone can be more firmly abutted against each other in the early postoperative period, thereby promoting bone ingrowth. Summary of the invention

[0004] In order to exert continuous pressure between the fixation stem and the retained bone, thereby promoting bone ingrowth and making the connection between the two more stable in the early postoperative period, the present application provides an intramedullary axial compression fixation prosthesis for epiphyseal bone defects.

[0005] The present application provides an intramedullary axial compression fixation prosthesis for epiphyseal bone defects using the following technical solution:

[0006] A metaphyseal bone defect intramedullary axial pressure fixation prosthesis comprises a pressure rod and a fixing part for fixing the position of the pressure rod, wherein the pressure rod extends into a fixing handle, a pressure tail cap threadedly connected to the pressure rod is arranged inside the fixing handle, a nut hole for inserting the pressure tail cap is provided on the fixing handle, the axial position of the pressure tail cap and the nut hole are fixed and can rotate inside the nut hole.

[0007] By adopting the above technical solution, when it is necessary to fix the fixing handle and the retained bone together, the pressure rod is inserted into the medullary cavity of the retained bone, and the pressure rod is fixed to the retained bone by the fixing piece; at this time, the pressure rod extends to the outside of the retained bone and is inserted into the fixing handle, and the pressure tail cap is rotated at this time to make the pressure tail cap rotate on the pressure rod and move in the direction close to the bottom of the nut hole until the pressure tail cap abuts against the bottom of the nut hole. At this time, if the pressure tail cap continues to be rotated, the pressure tail cap will drag the pressure rod and make the pressure rod tend to move along its own axis toward the outside of the medullary cavity. In this process In the process, the pressure tail cap pushes the entire fixing handle to continuously make small movements toward the direction of the retained bone through the bottom of the nut hole and presses on the cross section of the retained bone. The mutual cooperation between the pressure tail cap and the pressure rod and the mutual abutment between the pressure tail cap and the bottom of the nut hole make there be a clamping force between the end face of the fixing handle and the cross section of the retained bone, thereby achieving the pressurization of the bone interface with a controllable pressure level through the fixing torque. On the one hand, it plays a more firm fixing role between the fixing part and the retained bone in the early postoperative period; on the other hand, the mutual pressure between the end face of the fixing handle and the cross section of the retained bone promotes the bone ingrowth effect.

[0008] Preferably, an anti-loosening member for maintaining a continuous pressurized state is provided between the pressure tail cap and the bottom of the nut hole.

[0009] By adopting the above technical solution, the possibility of the pressure tail cap loosening is reduced.

[0010] Preferably, an anti-rotation groove extending in its radial direction is formed on the circumferential surface of the pressure rod, and an anti-rotation screw is threadedly connected to the fixing handle. The anti-rotation screw extends into the anti-rotation groove and is slidably connected to the pressure rod.

[0011] By adopting the above technical solution, on the one hand, it can guide the movement of the pressure rod; on the other hand, the anti-rotation screw is rotated until the end of the anti-rotation screw abuts against the bottom of the anti-rotation groove, thereby further fixing the position of the pressure rod.

[0012] Preferably, one or more fixing members are provided, and the fixing members are locking screws connected to the pressure rod, and an axis of the locking screw and an axis of the pressure rod form an angle.

[0013] By adopting the above technical solution, since there is an angle between the axis of the locking screw and the axis of the pressure rod, when the pressure rod is to be pulled out from the medullary cavity along its own axis, the locking screw can fix the positional relationship between the pressure rod and the retained bone, and then when the pressure tail cap is rotated, the pressure rod can also drag the retained bone to press the cross section of the retained bone against the end face of the fixing handle.

[0014] Preferably, an intramedullary rod for implantation into the retained bone is provided at the end of the fixation stem.

[0015] By adopting the above technical solution, on the one hand, radial dislocation between the fixation stem and the retained bone can be prevented, and on the other hand, bone ingrowth occurs in the intramedullary rod, thereby improving the bone ingrowth effect of the fixation stem and the retained bone.

[0016] Preferably, the surface of the intramedullary rod and the end surface of the fixing handle are both treated with a coating that can promote bone ingrowth.

[0017] By adopting the above technical solution, a better rehabilitation effect is achieved.

[0018] Preferably, it comprises a steel plate for fixing the retained bone and the fixed handle, the steel plate is provided with a plurality of fixing screws for fixing the steel plate to the retained bone and the fixed handle; a plurality of screw holes for the fixing screws to pass through are opened at one end of the steel plate close to the locking screws.

[0019] In summary, this application has the following technical effects:

[0020] 1. By providing a locking screw, a pressure rod and a pressure tail cap, and opening a nut hole on the fixing handle, a continuous pressing force is created between the end face of the fixing handle and the cross section of the retained bone. On the one hand, this provides a more secure fixation between the fixing part and the retained bone in the early postoperative period; on the other hand, the mutual pressure between the end face of the fixing handle and the cross section of the retained bone promotes the bone ingrowth effect;

[0021] 2. By setting an anti-rotation screw, an anti-rotation groove is opened on the pressure rod, which can guide the movement of the pressure rod on the one hand; on the other hand, the anti-rotation screw is rotated until the end of the anti-rotation screw abuts against the bottom of the anti-rotation groove, thereby further fixing the position of the pressure rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure in which the retained bone and the fixed handle are installed through a steel plate and a fixing screw;

[0023] Figure 2 is a schematic diagram of the internal structure of the retained bone and the fixed handle in the embodiment of the present application;

[0024] Figure 3 It is a schematic diagram of the partial structure of the anti-rotation screw inside the fixed handle in the embodiment of the present application;

[0025] Figure 4 It is an exploded view between the torque wrench and the pressure tail cap in the embodiment of the present application.

[0026] In the figure, 1. retained bone; 11. medullary cavity; 2. fixing handle; 21. nut hole; 22. pressure rod hole; 3. pressure rod; 31. anti-rotation groove; 32. intramedullary rod; 4. pressure tail cap; 41. screwing part; 5. anti-loosening part; 6. anti-rotation screw; 7. locking screw; 8. steel plate; 81. screw hole; 9. fixing screw; 10. torque wrench. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with the accompanying drawings.

[0028] Reference Figure 1 and Figure 2 The present application provides an intramedullary axial pressure fixation prosthesis for epiphyseal bone defects, comprising a pressure rod 3 inserted into a retained bone 1, that is, the pressure rod 3 is inserted into the medullary cavity 11, and a fixing member for fixing the pressure rod 3 on the retained bone 1 is installed on the retained bone 1; the pressure rod 3 extends to the outside of the medullary cavity 11 and coaxially extends to the inside of a fixing handle 2, and the end of the pressure rod 3 away from the retained bone 1 is fixed to the fixing handle 2, and is further configured to coaxially open a pressure rod hole 22 for inserting the pressure rod 3 on the fixing handle 2; the end of the fixing handle 2 close to the retained bone 1 is coaxially integrally formed with an intramedullary rod 32 inserted into the medullary cavity 11, and the intramedullary rod 32 can be customized according to the shape of the medullary cavity, and can also be a column or a vertebral body. In this embodiment, the intramedullary rod 32 is a cylindrical structure; the pressure rod 3 also penetrates the intramedullary rod 32. In order to provide a better bone ingrowth effect, the surface of the intramedullary rod 32 and the end face of the fixing handle 2 are coated with a coating that can promote bone ingrowth, and the coating includes but is not limited to a 3D printed trabecular porous structure, a titanium / tantalum spray coating, a hydroxyapatite coating, etc.; a steel plate 8 for fixing the retained bone 1 and the fixing handle 2 is provided on one side of the fixing handle 2, and a fixing screw 9 is provided at one end of the steel plate 8 close to the fixing handle 2 and the end of the steel plate 8 close to the retained bone 1, that is, the two ends of the steel plate 8 are respectively fixedly connected to the fixing handle 2 and the retained bone 1 by the fixing screws 9; at this point, the fixed connection between the fixing handle 2 and the retained bone 1 is achieved.

[0029] At least one fixing member is provided, and the fixing member is a locking screw 7 that penetrates the retained bone 1. In the present embodiment, two locking screws 7 are provided, and in other embodiments, one or more locking screws may be provided. The horizontal direction may be at any angle, and the locking screw is kept perpendicular to the pressure rod in the coronal direction or the parasternal direction; the locking screw 7 penetrates the pressure rod 3 along the radial direction of the pressure rod 3 and is connected to the pressure rod 3; there is an angle between the two locking screws 7 in the radial direction of the pressure rod 3; when the pressure rod 3 is about to be dislocated with the retained bone 1 along its own radial direction, the axial misalignment of the two locking nuts can hinder the movement trend of the pressure rod 3, that is, the pressure rod 3 can be more firmly fixed on the retained bone 1; a plurality of screw holes 81 are provided on the steel plate 8 for the locking screws 7 to be selectively inserted, and by providing a plurality of screw holes 81, the position of the locking screw 7 can be selected according to the position of the fixing screw 9.

[0030] Reference Figure 2 and Figure 3 In order to create a mutual pressure between the end face of the fixing handle 2 and the cross-section of the retained bone 1 that can promote bone ingrowth, a nut hole 21 connected to the pressure rod hole 22 is opened at the end of the fixing handle 2 away from the retained bone 1, and the nut hole 21 passes through the end face of the fixing handle 2 away from the retained bone 1; a pressure tail cap 4 is threadedly connected to the end of the pressure rod 3 away from the retained bone 1 inside the nut hole 21, and the pressure tail cap 4 is provided with at least one. In this embodiment, two pressure tail caps 4 are provided and the two pressure tail caps 4 abut against each other; at least one anti-loosening member 5 is provided between the pressure tail cap 4 on the side close to the retained bone 1 and the bottom of the pressure rod hole 22, and the anti-loosening member 5 can be a spring washer or a butterfly washer. In this embodiment, the anti-loosening member 5 adopts a spring washer and is provided with two spring washers, which are pressed between the bottom of the pressure rod hole 22 and the pressure tail cap 4 on the side close to the retained bone 1.

[0031] When the pressure rod 3, the fixing handle 2, the steel plate 8 and the fixing screw 9 are installed, the two pressure tail caps 4 are screwed into the nut hole 21 in turn, and at the same time, the pressure tail cap 4 is screwed onto the pressure rod 3 until the pressure tail cap 4 presses the spring washer against the bottom of the nut hole 21, and the pressure tail cap 4 on the side away from the retained bone 1 is pressed against the pressure tail cap 4 on the side close to the retained bone 1; during this process, the pressure tail cap 4 will drag the pressure rod 3 and make the pressure rod 3 tend to move toward the outside of the medullary cavity 11 along its own axial direction. During this process, the pressure tail cap 4 pushes the fixing handle 2 and makes the fixing handle 2 tend to move toward the retained bone 1 and then be pressed against the cross section of the retained bone 1. In addition, due to The pressure rod 3 also has a tendency to move outside the medullary cavity 11, and the pressure rod 3 then drives the retained bone 1 to move toward the fixed handle 2. The mutual cooperation between the pressure tail cap 4 and the pressure rod 3, the mutual abutment between the pressure tail cap 4 and the bottom of the nut hole 21, and the fixed connection between the pressure rod 3 and the retained bone 1 together make the end face of the fixed handle 2 and the cross section of the retained bone 1 have a tendency to move toward each other, and there is mutual pressure between the end face of the fixed handle 2 and the cross section of the retained bone 1. In this way, on the one hand, it plays a more secure fixing role between the fixing part and the retained bone 1 in the early postoperative period; on the other hand, the mutual pressure between the end face of the fixed handle 2 and the cross section of the retained bone 1 promotes the bone ingrowth effect.

[0032] By setting two pressure tail caps 4, the two pressure tail caps 4 push each other so that the screw threads of the two pressure tail caps 4 can be pressed against the screw threads of the pressure rod 3, that is, further pre-tightening force is applied between the pressure tail cap 4 and the pressure rod 3, which plays an anti-loosening effect; in addition, the anti-loosening component 5, that is, the spring washer or the butterfly washer, also plays an anti-loosening effect, which is further explained as follows: after the pressure tail cap 4 applies pressure to the spring washer or the butterfly washer, the spring washer or the butterfly washer will generate a continuous elastic force, so that the threaded connection pair of the pressure tail cap 4 and the pressure rod 3 continues to maintain a larger friction force, generating a resistance torque, thereby reducing the possibility of loosening of the pressure tail cap 4.

[0033] Reference Figure 4 In order to achieve the above-mentioned "screwing the pressure tail cap 4 onto the pressure rod 3", it is further configured that a screwing portion 41 is integrally formed at the end of the pressure tail cap 4 away from the retained bone 1, and the screwing portion 41 is a polygonal structure. In the present embodiment, the screwing portion 41 is a quadrilateral structure, and the two opposite sides of the screwing portion 41 are straight sides and the other two opposite sides are arc sides with the same curvature as the pressure tail cap 4; when it is necessary to screw the pressure tail cap 4, a torque wrench 10 is required, and a groove matching the shape of the screwing portion 41 is provided at the end of the torque wrench 10; in this way, the torque wrench 10 is installed on the screwing portion 41, and the pressure tail cap 4 can be screwed onto the pressure rod 3 by rotating the torque wrench 10.

[0034] Reference Figure 2 and Figure 3 Furthermore, an anti-rotation groove 31 is opened on the circumferential surface of the pressure rod 3 along its own axial direction, and an anti-rotation screw 6 is threadedly connected to the circumferential wall of the fixing handle 2, the axis of the anti-rotation screw 6 is perpendicular to the axis of the pressure rod 3 and the anti-rotation screw 6 extends to the inside of the anti-rotation groove 31; the groove width of the anti-rotation groove 31 along the direction perpendicular to the axis of the pressure rod 3 is equal to the diameter of the anti-rotation screw 6; in this way, when the pressure tail cap 4 is rotated to make the pressure rod 3 move slightly along its own axial direction, the mutual cooperation between the anti-rotation groove 31 and the anti-rotation screw 6 can, on the one hand, guide the movement of the pressure rod 3; on the other hand, when the position of the pressure rod 3 is determined, the anti-rotation screw 6 is rotated until the end of the anti-rotation screw 6 abuts against the bottom of the anti-rotation groove 31, thereby further fixing the position of the pressure rod 3.

[0035] To summarize, the use process of the present application is as follows: insert the pressure rod 3 into the medullary cavity 11 and install two locking screws 7 on the pressure rod 3; then insert the fixing handle 2 onto the axial end of the pressure rod 3 extending to the outside of the retained bone 1 until the end face of the fixing handle 2 fits the cross section of the retained bone 1; put the anti-loosening piece 5 and the pressure tail cap 4 on the pressure rod 3 in sequence, and rotate the pressure tail cap 4 with the torque wrench 10 until the pressure tail cap 4 presses the anti-loosening piece 5 against the bottom of the nut hole 21. At this time, the fixing handle 2 and the retained bone 1 tend to move closer to each other, thereby generating mutual pressure between the surfaces of the two fitting together. On the one hand, it plays a more secure fixing role between the fixing part and the retained bone 1 in the early postoperative period; on the other hand, the mutual pressure between the end face of the fixing handle 2 and the cross section of the retained bone 1 promotes the bone ingrowth effect; finally, select a suitable screw hole 81 to fix the steel plate 8 to the fixing handle 2 and the retained bone 1 through the fixing screws 9.

[0036] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An intramedullary axial compression fixation prosthesis for metaphyseal bone defects, characterized in that: The invention comprises a pressure rod (3) and a fixing member for fixing the position of the pressure rod (3); the pressure rod (3) extends into the fixing handle (2); a pressure tail cap (4) threadedly connected to the pressure rod (3) is arranged inside the fixing handle (2); a nut hole (21) for inserting the pressure tail cap (4) is provided on the fixing handle (2); the axial position of the pressure tail cap (4) and the nut hole (21) are fixed and the pressure tail cap (4) can rotate inside the nut hole (21); a pressure tail cap (4) for implanting is arranged at the end of the fixing handle (2); An intramedullary rod (32) is retained inside the bone (1); the surface of the intramedullary rod (32) and the end surface of the fixing handle (2) are both treated with a coating that can promote bone ingrowth; one or more fixing members are provided, and the fixing member is a locking screw (7) connected to the pressure rod (3); the intramedullary rod (32) is a cylindrical structure; the pressure rod (3) also penetrates the intramedullary rod (32), and the locking screw (7) penetrates the pressure rod (3) along the radial direction of the pressure rod (3) and is connected to the pressure rod (3).

2. The intramedullary axial compression fixation prosthesis for metaphyseal bone defects according to claim 1, characterized in that: An anti-loosening component (5) for maintaining a continuous pressurized state is provided between the pressure tail cap (4) and the bottom of the nut hole (21).

3. The intramedullary axial compression fixation prosthesis for metaphyseal bone defects according to claim 1 or 2, characterized in that: An anti-rotation groove (31) extending in its radial direction is provided on the circumferential surface of the pressure rod (3); an anti-rotation screw (6) is threadedly connected to the fixed handle (2); the anti-rotation screw (6) extends into the anti-rotation groove (31) and is slidably connected to the pressure rod (3).

4. The intramedullary axial compression fixation prosthesis for metaphyseal bone defects according to claim 1, characterized in that: The invention comprises a steel plate (8) for fixing a retained bone (1) and a fixed handle (2); the steel plate (8) is provided with a plurality of fixing screws (9) for fixing the steel plate (8) to the retained bone (1) and the fixed handle (2); and a plurality of screw holes (81) for the fixing screws (9) to pass through are provided at one end of the steel plate (8) close to the locking screw (7).

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