Femoral isthmus shaping porous steel plate system

Abstract

The present invention discloses a porous steel plate system for forming the isthmus of the femur, characterized in that: it comprises a steel plate body and an isthmus forming block; a porous structure is formed on the inner side surface of the steel plate body in contact with the cortical bone; the isthmus forming block is convexly arranged on the inner side surface of the steel plate body, and the side surface of the isthmus forming block in contact with the cortical bone is formed as an extrusion surface with a lower upper part and a higher lower part, and a porous structure is formed on the extrusion surface; the present invention enables patients with severe bone defects of the femur to obtain morphological reconstruction of the isthmus, improves the effective fixation length of the cementless femoral stem prosthesis and the femur, and improves the initial and long-term fixation effect of the cementless femoral stem prosthesis for treating severe bone defects of the femur. In addition, the porous structure enables the steel plate system to obtain long-term bone ingrowth fixation after surgery, improves the overall strength of the femoral prosthesis, reduces the risk of long-term periprosthetic fractures, improves the short-term and long-term efficacy of hip surgery, and enables patients to obtain better hip function.

Description

Technical Field

[0001] The invention relates to a device for treating severe femoral defects in artificial hip joint revision surgery, in particular to a femoral isthmus forming porous steel plate system, belonging to the technical field of medical devices. Background Art

[0002] Artificial hip replacement is an effective means of treating various end-stage hip arthritis. Artificial hip revision surgery is a method for treating various failed artificial hip replacements. Due to severe osteolysis caused by loosening or wear, stress shielding, periprosthetic infection, multiple surgical history, osteoporosis, iatrogenic bone defects caused by perforation or fenestration when removing the original prosthesis or residual bone cement, the femoral side is often faced with varying degrees of bone defects during artificial hip revision surgery. The difficulty of reconstruction lies in the fact that there are often severe bone defects on the femoral side. At the same time, the femur is often combined with proximal anatomical remodeling during revision surgery, such as varus or retroversion remodeling. Therefore, the reconstruction strategy of femoral bone defects is determined based on the severity of the bone defect, the remaining bone mass and quality, and the changes in anatomical remodeling.

[0003] Many scholars have proposed classifications for femoral bone defects, among which the most widely used classification is the Paprosky classification, which takes into account three factors: the site of bone defect (metaphysis or diaphysis), the remaining bone volume and support of the proximal femur, and the length of the isthmus of the diaphysis that can be used for distal fixation. Based on this classification, doctors can objectively evaluate femoral bone defects and choose appropriate reconstruction methods based on the defect classification. For severe femoral bone defects, especially those in which the medullary cavity forms a trumpet-shaped structure that expands downward or the femoral medullary cavity expands and expands into a stovepipe shape, resulting in a bone defect with no isthmus of the diaphysis for femoral stem fixation, traditional reconstruction methods such as combined conical ridged titanium stems, impaction bone grafting, proximal femoral allograft bone-prosthesis complexes, and proximal femoral replacement can be selected. The incidence of early prosthesis subsidence after combined conical ridged titanium stems is high, and the risk of intraoperative or postoperative fractures is increased. It may also lead to a series of complications such as stress concentration, stress shielding, insufficient effective fixation length, and unreliable prosthesis fixation. Proximal femoral allograft-prosthesis complexes have potential risks such as disease transmission, graft bone absorption and nonunion, aseptic loosening, periprosthetic fracture and infection. Proximal femoral replacement has a high dislocation rate and a low long-term survival rate, and is only suitable as a stopgap measure for elderly patients with low activity and a large number of severe bone defects. Although compression bone grafting has the potential to rebuild the patient's bone mass in theory, it has a high risk of intraoperative fracture and postoperative prosthesis sinking, and has disadvantages such as high surgical technical requirements, time-consuming, disease transmission risk, and bone graft absorption. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a femoral isthmus forming porous steel plate system, which is suitable for the reconstruction of severe femoral bone defects, can overcome the drawbacks of existing traditional reconstruction methods, and improve the treatment effect of hip revision patients with severe femoral bone defects.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a porous steel plate system for forming the isthmus of a femur, comprising a steel plate body and an isthmus forming block; a porous structure is formed on the inner side surface of the steel plate body in contact with the cortical bone; the isthmus forming block is protrudingly arranged on the inner side surface of the steel plate body, and the side surface of the isthmus forming block in contact with the cortical bone is formed as an extrusion surface which is lower at the top and higher at the bottom, and a porous structure is formed on the extrusion surface.

[0006] In some embodiments, the isthmus forming block is a wedge-shaped protrusion longitudinally arranged on the inner side surface of the steel plate body, and the side of the wedge-shaped protrusion that contacts the cortical bone is a sloped surface that is lower on the top and higher on the bottom.

[0007] In some embodiments, the isthmus forming block is a plurality of first protrusions longitudinally spaced apart on the inner side surface of the steel plate body, the height of the first protrusions gradually increases from top to bottom, and the sides of the plurality of first protrusions away from the steel plate body together constitute an extrusion surface.

[0008] In some embodiments, the side surface of each first protrusion away from the steel plate body is an inclined surface, and the side surfaces of multiple first protrusions away from the steel plate body are all located on the same inclined surface, and the inclined surface is arranged to be inclined downward relative to the steel plate body.

[0009] In some embodiments, a plurality of second protrusions are spaced apart on the inner side surface and the extrusion surface along the length direction of the steel plate body, and a porous structure is formed on the second protrusions.

[0010] In some embodiments, the second protrusion is an arc-shaped strip protrusion extending along the width direction of the inner side surface or the extrusion surface.

[0011] In some embodiments, a porous structure is formed on the surface of the isthmus forming block adjacent to the extrusion surface.

[0012] In some embodiments, the porous structure is a trabecular porous structure.

[0013] In some embodiments, the cross-section of the steel plate body is an arc-shaped cross-section, a rectangular cross-section or a trapezoidal cross-section, and the thickness of the steel plate body gradually decreases from the middle to both ends. A plurality of cable grooves are arranged on the outer surface of the steel plate body and at intervals along its length direction.

[0014] In some embodiments, the steel plate body and the isthmus forming block are integrally formed, the total length of the steel plate body is 6cm to 18cm, the width of the steel plate body is 1cm to 2cm, the thickness of the porous structure of the steel plate body is 1mm to 3mm, and the overall thickness of the steel plate body is 3mm-11mm; the length of the isthmus forming block is 2 to 6cm, the width is 0.5cm to 1.5cm, the height of the maximum cross section on the isthmus forming block is the medullary cavity diameter at the same level minus 12 to 16mm, preferably 3mm to 20mm; the pore size of the porous structure is 700μm±300μm.

[0015] The present invention adopts the above technical scheme, which has the following advantages: the porous steel plate system provided by the present invention includes a steel plate main body and an isthmus forming block, a porous structure is formed on the inner side surface of the steel plate main body in contact with the cortical bone, the isthmus forming block is convexly arranged on the inner side surface of the steel plate main body, and the side surface of the isthmus forming block in contact with the cortical bone is formed as an extrusion surface which is lower at the top and higher at the bottom, the steel plate main body can be fixed to the outer side of the femur by a titanium cable or a steel wire, the isthmus forming block squeezes the tongue-shaped cortical bone strip formed after osteotomy, so that the femoral medullary cavity is deformed, and an artificial femoral isthmus is formed in the femoral medullary cavity, so that patients with severe femoral bone defects can obtain morphological reconstruction of the isthmus, increase the effective fixation length of the non-bone cement femoral stem prosthesis and the femur, and improve the initial and long-term fixation effect of the non-bone cement femoral stem prosthesis for treating severe femoral bone defects. At the same time, the porous structure can enable the steel plate system to achieve long-term bone ingrowth fixation after surgery, which can improve the overall strength of the femur-prosthesis, reduce the risk of long-term periprosthetic fractures, improve the short-term and long-term efficacy of hip surgery, and enable patients to obtain better hip joint function; the porous steel plate system of the present invention can be designed according to patient specificity, and can avoid the use of traditional methods such as allogeneic bone-prosthesis complexes, compression bone grafting combined with long cement stems or proximal femoral replacement, thereby improving the therapeutic efficacy of hip revision patients with severe femoral bone defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a structural schematic diagram of a porous steel plate system provided by an embodiment of the present invention;

[0017] Figure 2 It is a structural schematic diagram of a porous steel plate system provided in another embodiment of the present invention. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0019] It should be noted that all directional indications in the present embodiment (such as proximal, distal, front end, rear end, inner side, outer side, upper end, lower end, etc.) are only used to explain the general medical description of the relative position relationship of the patient's parts, movement conditions, etc., that is, the side close to the patient's head is called the proximal end, and the side away from the patient's head is called the distal end; the front of the patient is the front side, and the back is the back side; the side close to the patient's midline is the inner side, and the side away from the patient's midline is the outer side.

[0020] like Figure 1 As shown, the present embodiment provides a femoral isthmus forming porous steel plate system, which includes a steel plate body 100 and an isthmus forming block 200; a porous structure is formed on the inner side surface 101 of the steel plate body 100 in contact with the cortical bone; the isthmus forming block 200 is protrudingly arranged on the inner side surface 101 of the steel plate body 100, and the side surface of the isthmus forming block 200 in contact with the cortical bone is formed as an extrusion surface 201 which is low at the top and high at the bottom, and a porous structure is formed on the extrusion surface 201.

[0021] When the present invention is in use, the steel plate body 100 is fixed on the femur, and the isthmus forming block 200 squeezes the tongue-shaped cortical bone strip formed after osteotomy inwardly, and the extrusion surface 201 of the isthmus forming block 200 abuts against the cortical bone, so that the femoral medullary cavity is deformed, thereby forming an artificial femoral isthmus that is larger at the top and smaller at the bottom in the femoral medullary cavity, overcoming the problem of the prior art that the medullary cavity forms a trumpet-shaped structure that expands downward or the femoral medullary cavity expands and expands into a chimney shape, resulting in the isthmus without a backbone for femoral stem fixation due to a large amount of bone defects, and realizing the reconstruction of the isthmus morphology in the femoral medullary cavity of patients with severe femoral bone defects, and can enhance the fixation of non-bone cement prosthesis, and a porous structure is formed on the inner side surface 101 of the steel plate body 100 and the extrusion surface 201 of the isthmus forming block 200, and the porous structure on the steel plate body 100 and the extrusion surface 201 of the isthmus forming block 200 is in contact with the cortical bone, and bone ingrowth can be obtained in the long term, which can improve the overall strength of the femur-prosthesis and improve the short-term and long-term efficacy of hip joint surgery.

[0022] In the above embodiment, preferably, the isthmus forming block 200 is a wedge-shaped protrusion 200a longitudinally arranged on the inner side surface 101 of the steel plate main body 100, and the side of the wedge-shaped protrusion 200a in contact with the cortical bone is a sloped surface that is low at the top and high at the bottom, and the sloped surface is the extrusion surface 201; when in use, the steel plate main body 100 can be fixed to the femur by a titanium cable or a steel wire, and the wedge-shaped protrusion 200a squeezes the tongue-shaped cortical bone strip formed after osteotomy toward the inside of the femoral medullary cavity, and the sloped surface of the wedge-shaped protrusion 200a is against the cortical bone, causing the femoral medullary cavity to deform, thereby forming a femoral isthmus in the femoral medullary cavity.

[0023] In the above embodiment, preferably, Figure 2As shown, the isthmus forming block 200 is a plurality of first protrusions 200b longitudinally spaced apart on the inner side surface of the steel plate body 100, the height of the first protrusions 200b gradually increases from top to bottom, and the plurality of first protrusions 200b away from the plurality of side surfaces of the steel plate body 100 together constitute an extrusion surface 201.

[0024] In the above embodiment, preferably, the side of each first protrusion 200b away from the steel plate body 100 is an inclined surface, and the sides of multiple first protrusions 200 away from the steel plate body 100 are all located on the same inclined surface, which is inclined downward relative to the steel plate body 100.

[0025] In the above embodiment, preferably, a plurality of second protrusions 300 are arranged at intervals along the length direction of the steel plate body 100 on the inner side surface 101 and the extrusion surface 201, and a porous structure is formed on the second protrusions 300. The second protrusions 300 are in contact with the cortical bone, which can greatly reduce the contact area between the inner side surface 101 and the extrusion surface 201 and the cortical bone, thereby reducing the interference with the blood supply to the cortical bone.

[0026] In the above embodiment, preferably, the second protrusion 300 is an arc-shaped strip protrusion extending along the width direction of the inner side surface 101 or the extrusion surface 201 .

[0027] In the above embodiment, preferably, a plurality of cable grooves 400 are provided on the outer surface of the steel plate body 100 and spaced apart along the length direction thereof to facilitate fixing of titanium cables or steel wires.

[0028] In the above embodiment, preferably, a porous structure is formed on the surface of the isthmus forming block 200 adjacent to the extrusion surface 201 .

[0029] In the above embodiments, preferably, the cross-section of the steel plate main body 100 can be an arc-shaped cross-section, a rectangular cross-section or a trapezoidal cross-section, and the thickness of the steel plate main body 100 gradually decreases from the middle to both ends, so that the structure of the steel plate main body 100 is more in line with human anatomy and biomechanics, and the steel plate main body 100 can be more closely fixed to the outside of the femur, thereby enhancing the stability of the fixation.

[0030] In the above embodiment, preferably, the porous structure is a trabecular porous structure, so that the long-term bone ingrowth fixation of the steel plate system can improve the overall reconstruction strength of the femoral prosthesis.

[0031] In the above embodiment, preferably, the steel plate body 100 and the isthmus forming block 200 are integrally formed. Specifically, the steel plate body 100 and the isthmus forming block 200 are integrally formed by 3D printing, for example, by electron beam melting 3D printing, and the printing material is but not limited to titanium alloy (Ti6Al4V).

[0032] In the above embodiment, preferably, the total length of the steel plate main body 100 is 6cm~18cm, preferably 11cm~14cm, the specific length of the steel plate main body 100 can be determined according to the isthmus forming length, the width of the steel plate main body 100 (the width here can be the actual width or the arc length, depending on the cross-sectional shape of the steel plate main body 100) is 1cm~2cm, the thickness of the porous structure of the steel plate main body 100 is 1mm~3mm, and the overall thickness of the steel plate main body 100 is 3mm-11mm.

[0033] In the above embodiment, preferably, the length of the isthmus forming block 200 is 2-6 cm, the width is 0.5 cm-1.5 cm, and the height of the maximum cross section on the isthmus forming block 200 is in principle the diameter of the medullary cavity at the same level thereof minus 12-16 mm.

[0034] In the above embodiment, preferably, the height of the maximum cross section on the isthmus forming block 200 is 3 mm to 20 mm.

[0035] In the above embodiment, preferably, the pore size of the porous structure is 700 μm±300 μm, and the porosity of the isthmus forming block 200 is 50% to 80%.

[0036] Additionally, based on the femoral isthmus forming porous steel plate system in any of the above embodiments, the present invention further provides a method for implanting the porous steel plate system, which comprises the following steps:

[0037] 1) Use the medullary cavity drill to file the medullary cavity until the medullary cavity drill is in close contact with the cortical bone, and then remove the medullary cavity drill;

[0038] 2) A tongue-shaped osteotomy is performed 2cm-3cm outside the relatively intact femoral cortical bone stump at the proximal end. The distal end of the tongue-shaped osteotomy is arc-shaped to avoid stress concentration leading to fractures during and after surgery. The purpose of this is to retain the relatively intact femoral cortical bone 2cm-3cm proximal to the osteotomy, reduce the risk of fracture during surgery, and use this 2cm-3cm relatively intact femoral cortical bone in combination with the tongue-shaped cortical bone strip to fix the femoral stem;

[0039] 3) Reinsert the intramedullary drill until it is in close contact with the cortical bone, place the steel plate body 100 on the surface of the tongue-shaped osteotomy block, and tie 2-3 titanium cables on the outside of the steel plate body 100 corresponding to the isthmus forming block; the first titanium cable is located outside the maximum cross-section on the isthmus forming block 200, and the second titanium cable is located 2cm-4cm proximal to the first titanium cable. Depending on whether the steel plate body 100 is tightly pressed onto the lateral femur, etc., the third titanium cable can be tied at 2cm-3cm distal to the first titanium cable or 2cm-3cm proximal to the second titanium cable. The tightness of the titanium cable is appropriate when the isthmus forming block 200 tightly squeezes the tongue-shaped osteotomy block to the surface of the intramedullary drill, so that the degree of isthmus forming can be controlled so that the tongue-shaped cortical bone strip can just form a tight press fit on the femoral stem.

[0040] 4) After the titanium cable is tied, the femoral stem is inserted using conventional methods.

[0041] The present invention is only described with the above embodiments, and the structure, location and connection of each component can be changed. Based on the technical solution of the present invention, any improvement or equivalent transformation of individual components based on the principle of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A femoral isthmus forming porous steel plate system, characterized in that: It comprises a steel plate body and an isthmus forming block; a porous structure is formed on the inner side surface of the steel plate body in contact with the cortical bone; the isthmus forming block is convexly arranged on the inner side surface of the steel plate body, and the side surface of the isthmus forming block in contact with the cortical bone is formed as an extrusion surface with a lower upper side and a higher lower side, and the extrusion surface is formed with a porous structure; The steel plate body is fixed on the femur, and the extrusion surface of the isthmus forming block abuts against the cortical bone of the femur, so that the femoral medullary cavity is deformed to form an artificial femoral isthmus.

2. The femoral isthmus forming porous steel plate system according to claim 1, characterized in that: The isthmus forming block is a wedge-shaped protrusion longitudinally arranged on the inner side surface of the steel plate body, and the side surface of the wedge-shaped protrusion contacting the cortical bone is a slope surface with a lower upper side and a higher lower side.

3. The femoral isthmus forming porous steel plate system according to claim 1, characterized in that: The isthmus forming block is a plurality of first protrusions longitudinally spaced apart on the inner side surface of the steel plate body, the height of the first protrusions gradually increases from top to bottom, and the side surfaces of the plurality of first protrusions away from the steel plate body together constitute an extrusion surface.

4. The femoral isthmus forming porous steel plate system according to claim 3, characterized in that: The side surface of each first protrusion away from the steel plate body is an inclined surface, and the side surfaces of multiple first protrusions away from the steel plate body are all located on the same inclined surface, and the inclined surface is arranged to be inclined downward relative to the steel plate body.

5. The femoral isthmus forming porous steel plate system according to claim 1, characterized in that: A plurality of second protrusions are arranged at intervals on the inner side surface and the extrusion surface along the length direction of the steel plate body, and a porous structure is formed on the second protrusions.

6. The femoral isthmus forming porous steel plate system according to claim 5, characterized in that: The second protrusion is an arc-shaped strip protrusion extending along the width direction of the inner side surface or the extrusion surface.

7. The femoral isthmus forming porous steel plate system according to claim 1, characterized in that: The isthmus forming block has a porous structure formed on the surface adjacent to the extrusion surface.

8. The femoral isthmus forming porous steel plate system according to claim 1, 5 or 7, characterized in that: The porous structure is a trabecular porous structure.

9. The femoral isthmus forming porous steel plate system according to claim 1, characterized in that: The cross section of the steel plate body is an arc-shaped cross section, a rectangular cross section or a trapezoidal cross section, and the thickness of the steel plate body gradually decreases from the middle to both ends. A plurality of cable grooves are arranged on the outer surface of the steel plate body and at intervals along its length direction.

10. The femoral isthmus forming porous steel plate system according to claim 1, characterized in that: The steel plate main body and the isthmus forming block are integrally formed, the total length of the steel plate main body is 6cm to 18cm, the width of the steel plate main body is 1cm to 2cm, the thickness of the porous structure of the steel plate main body is 1mm to 3mm, and the overall thickness of the steel plate main body is 3mm-11mm; the length of the isthmus forming block is 2 to 6cm, the width is 0.5cm to 1.5cm, the height of the maximum cross section on the isthmus forming block is the medullary cavity diameter at the same level minus 12 to 16mm; the pore size of the porous structure is 700μm±300μm.

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