Metal 3D printed customized sleeve assembly femoral intramedullary pin prosthesis

Abstract

The present invention relates to a metal 3D printing customized sleeve assembly type femoral intramedullary needle prosthesis, comprising a sleeve and an intramedullary needle type femoral stem, the sleeve is prepared by 3D printing of metal materials, the outer surface of the sleeve is a microporous structure and matches the shape of the medullary cavity of the proximal femur, the sleeve is provided with a notch, the inner surface has a taper, and the shoulder is provided with a locking screw hole for fixed connection with other fixing devices; the intramedullary needle type femoral stem comprises a femoral connector, a neck body and a handle body connected in sequence, the outer surface of the neck body has a taper matching the sleeve, the handle body has a front bow, and the distal end of the handle body is provided with a locking nail hole for fixing with the distal end of the femur; the intramedullary needle type femoral stem is inserted into the sleeve, the femoral connector is nested with the notch, and the sleeve and the neck body are fixed by a taper press fit in the assembly fixed position. The present invention can achieve proximal biological fixation, and the distal end can achieve anti-rotation and prevent the prosthesis from sinking early through the locking nail hole and screw of the handle body.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial prostheses, and in particular to a metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis. Background Art

[0002] For elderly patients with intertrochanteric comminuted fractures and proximal femoral inclusion defects after hip replacement who need revision, the current treatment measures mainly use a biological extended stem and perform tight press-fit fixation through the distal femoral isthmus, such as Figure 1 and Figure 2 As shown; bone cement extended stems can also be used for patients with poor bone quality and bone volume. However, long-term follow-up found that most of these distal fixed prostheses do not have an anatomical anterior arch design, which can easily cause the distal femoral prosthesis tip to penetrate, with poor anti-rotation effect, proximal femoral stress shielding, bone absorption, causing the prosthesis to sink and fail, and requiring another revision surgery within a short period of time. Figure 3 and Figure 4 The following are schematic diagrams of different biological types of extended handle fixation methods after revision surgery. Patients with greater trochanter fractures often need additional internal fixators to fix the fracture, which results in additional costs and increases the burden on patients. Bone cement prostheses are not recommended in clinical practice because of the possibility of fatal bone cement allergic reactions during surgery and the difficulty of revision after loosening.

[0003] Therefore, for elderly patients with intertrochanteric fractures and postoperative proximal femoral inclusionary bone defects, the proximal plus isthmus fixed prosthesis should be used as the first choice. It should be pointed out that a considerable proportion of the proximal femoral anatomy of the adult hip joint does not match the geometry of the most common femoral prosthesis in total hip arthroplasty. A CT-based study showed that only 25% of the hip joint anatomy had good consistency with the femoral prosthesis (the distance was less than 2 mm), while 29% of the hip joints had a considerable mismatch with the femoral prosthesis (the distance was ≥ 6 mm). In this context, some studies have pointed out the differences in femoral anatomy among the global population, and the size of the prosthesis developed in Europe may not be optimal for people in other continents. At the same time, due to individual differences, the anatomical morphology and bone quality of the proximal femoral medullary cavity are different. It is not easy to achieve mass production of proximal matching integrated prostheses, which cannot form proximal stability, and the prosthesis anti-rotation effect is poor, and the prosthesis is prone to sinking.

[0004] In summary, in order to obtain the best intramedullary femoral stem filling and restore the patient's individualized hip biomechanics, modular femoral prostheses with various shapes and eccentricity options can make the metaphysis have better adaptability. Summary of the invention

[0005] In order to solve the problems existing in the artificial prosthesis used for the treatment of intertrochanteric fractures and hip replacement in the prior art, the present invention provides a metal 3D printed customized sleeve assembly type femoral intramedullary nail prosthesis.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis, comprising a sleeve and an intramedullary pin type femoral stem;

[0008] The sleeve is made of metal material through 3D printing and customization. The outer surface of the sleeve is a microporous structure and matches the shape of the medullary cavity of the proximal femur. The sleeve is hollow and cylindrical as a whole. A notch is provided on the side wall near the upper end, and a taper is provided on the inner surface of the side wall near the lower end. A locking screw hole for fixed connection with other fixing devices is provided on the shoulder opposite to the notch.

[0009] The intramedullary pin-type femoral stem comprises a femoral connector, a neck body and a stem body which are connected in sequence, the outer surface of the neck body has a taper matching the sleeve, the stem body has a front bow, and the distal end of the stem body is provided with a locking nail hole for fixing with the distal end of the femur;

[0010] The connection and fixing method between the sleeve and the intramedullary needle-type femoral stem is: the intramedullary needle-type femoral stem is inserted into the sleeve, the femoral connector is nested with the notch, and the sleeve and the neck are fixed by a taper press fit in the assembled and fixed position.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] (1) The present invention uses a sleeve made of metal material 3D printing and customized preparation, and matches it with the intramedullary pin-type femoral stem that can be mass-produced through taper, so as to achieve proximal biological fixation, and the locking nail holes and screws of the handle body at the distal end are used to achieve anti-rotation and prevent the prosthesis from sinking early, thereby further improving the stability of the prosthesis;

[0013] (2) The sleeve in the present invention is made of metal material by 3D printing and customization, and can match the shape of the medullary cavity of the proximal femur, solving the problem that the current artificial hip prosthesis does not match the proximal femoral fracture in the treatment of intertrochanteric fractures. The complete match increases the fixation strength of the prosthesis, and also solves the problem of reduced proximal femoral bone mass and decreased bone strength caused by distal fixation and stress shielding of the artificial prosthesis, thereby reducing complications;

[0014] (3) The shoulder of the sleeve near the proximal femur is extended, which can be used to fix greater trochanter fractures, solve the problem of incomplete greater trochanter and difficulty in reconstructing femoral abduction function, and avoid the use of additional steel plates on the outside to increase costs, reduce costs, and alleviate the burden on patients. At the same time, the shoulder of the sleeve is provided with locking screw holes, making the prosthesis more expandable, and can provide a fixed interface for patients with greater trochanter fractures who need abductor muscle reconstruction, thereby achieving the purpose of restoring the patient's hip abduction function.

[0015] (4) Metal 3D printing technology can produce more advanced prosthesis coatings. The present invention facilitates bone ingrowth through the microporous structure design on the outer surface of the sleeve, so that the prosthesis and the bone have better initial stability, thereby achieving the purpose of biological fixation of bone ingrowth in the long term;

[0016] (5) The stem of the intramedullary pin-type femoral stem has an anterior bow to prevent the distal end of the femur from penetrating. At the same time, a locking nail hole is provided at the distal end of the stem, which not only increases the vertical and rotational stability of the prosthesis and prevents the prosthesis from rotating and sinking, but can also be used to fix periprosthetic fractures.

[0017] (6) The sleeve and the intramedullary pin-type femoral stem in the present invention are fixed by a taper press fit. This fixing method reduces the difficulty of manufacturing the femoral stem, and the function of the femoral stem prosthesis is changed from matching and fixing with the femur to connecting the sleeve and the femur. This new fixing method reduces the wear of the femur in traditional prosthesis replacement surgery and preserves the bone mass of the distal femur. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a biological type lengthened handle in the prior art being tightly press-fitted and fixed through the distal isthmus of the femur;

[0019] Figure 2 Another schematic diagram of the prior art of the biological type elongated stem being tightly press-fitted and fixed through the distal isthmus of the femur;

[0020] Figure 3 This is a schematic diagram of the bio-type extended stem fixation method after revision surgery;

[0021] Figure 4 Another schematic diagram of the bio-type extended stem fixation method after revision surgery;

[0022] Figure 5 It is a schematic diagram of the three-dimensional structure of the metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis according to the present invention;

[0023] Figure 6 It is a front view of the metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis according to the present invention;

[0024] Figure 7This is a left view of the metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis of the present invention;

[0025] Figure 8 is a three-dimensional diagram of the sleeve in the present invention;

[0026] Fig. 9 It is a front view of the sleeve in the present invention;

[0027] Fig.10 It is a right side view of the sleeve in the present invention;

[0028] Fig.11 is a top view of the sleeve in the present invention;

[0029] Fig.12 A stereoscopic view of the intramedullary needle-type femoral stem of the present invention;

[0030] Fig.13 It is a front view of the intramedullary pin-type femoral stem of the present invention;

[0031] Fig.14 It is a left view of the intramedullary needle-type femoral stem in the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0033] like Figure 5-Figure 7 As shown, the present invention provides a metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis, which comprises a sleeve 1 and an intramedullary pin-shaped femoral stem 2 matched with the sleeve 1. The prosthesis of the present invention adopts a proximal fixation mode, uses a 3D printed individualized customized sleeve to achieve matching fixation of the proximal femur, and has a front arch intramedullary pin-like long handle with distal locking to prevent rotation and prosthesis sinking, thereby further achieving prosthesis stability.

[0034] Specifically, the sleeve 1 is made of metal material by 3D printing and customization. The outer surface of the sleeve 1 is a microporous structure, and the outer surface of the sleeve 1 matches the shape of the proximal femoral medullary cavity, so as to achieve the purpose of tightly press-fitting and fixing the sleeve 1 and the femoral medullary cavity. Figure 8-Figure 11 As shown, the sleeve 1 is in the shape of a hollow cylinder as a whole, a notch is provided on the side wall near the upper end, a tapered inner surface of the side wall near the lower end, and a locking screw hole 3 is provided on the shoulder opposite to the notch for fixing with other fixing devices.

[0035] The sleeve 1 in the present invention is a 3D printed customized component, which is manufactured based on the imaging data of the patient's proximal femur and can completely match the inner wall of the proximal femur cortex to provide reliable initial mechanical stability. Further, the preparation process of the sleeve 1 includes the following steps:

[0036] Step 1: Obtain imaging data of the patient's proximal femur;

[0037] Step 2: Create a customized 3D digital model based on imaging data;

[0038] Step 3: Print and produce the sleeve based on the 3D digital model using metal materials.

[0039] The sleeve 1 prepared individually through the above steps can achieve a complete match with the proximal femoral medullary cavity, and the complete match increases the fixation strength of the prosthesis.

[0040] The metal 3D printed sleeve component of this product uses imaging data to create a 3D digital model, and a fully matched metal 3D printed component is individually produced according to the reconstructed proximal femoral morphology;

[0041] Although 3D printing technology has been widely used in the manufacture of orthopedic devices such as prostheses, it is still difficult to prepare all prostheses using 3D printing technology. The process is not only complicated, but also takes a long time to print and has high material costs. The present invention uses 3D printing technology to prepare a sleeve 1. By making a prosthesis at a key position, it not only solves the key problem of fixation, but also reduces the printing time cost and material cost, and can solve the key problem of prosthesis implantation after proximal femoral defect in clinical practice.

[0042] Optionally, the metal material used to prepare the sleeve 1 in the present invention is titanium alloy. Currently, the main metal material for artificial joints is titanium alloy. During the development of some new materials, the main purpose is to solve the problem that the large material coefficient difference between metal and bone tissue leads to stress shielding and affects the survival rate of the prosthesis.

[0043] The outer surface of the sleeve 1 is designed with a microporous structure to facilitate bone ingrowth, so that the sleeve 1 can achieve long-term biological fixation with the femur through bone ingrowth in the later stage. Optionally, the microporous structure is a cubic structure, the porosity of the cubic structure is 70%, and the micropore diameter ranges from 200 to 400 μm, for example, the micropore diameter can be 200 μm, 320 μm and 400 μm.

[0044] Preferably, in order to achieve the best bone ingrowth effect in in vivo experiments, the micropore diameter is 320 μm.

[0045] The shoulder of the sleeve 1 is designed with a locking screw hole 3 as required to connect other fixing devices to cooperate with the femoral abduction reconstruction device, wherein the other fixing devices can be internal fixing devices, such as steel plates.

[0046] Preferably, the number of the locking screw holes 3 is 6, and the diameter of each locking screw hole 6 is 3.5 mm. The hole spacing of the locking screw holes 3 can be designed as long as it meets the fixing purpose, and can be specifically designed according to the requirements of the CAD model.

[0047] like Figure 12-14As shown, the intramedullary needle-type femoral stem 2 includes a femoral connector 4, a neck body 5 and a stem body 6 which are connected in sequence. The outer surface of the neck body 5 has a taper matching the sleeve 1. The stem body 6 has a front bow, and a locking nail hole 7 is provided at the distal end of the stem body 6. The locking nail hole 7 can be screwed in transversely to fix the stem body 6 to the distal end of the femur to prevent the initial sinking and rotation of the prosthesis.

[0048] The intramedullary needle-type femoral stem 2 of the present invention can be set in batches to produce different diameter models, and the corresponding model of the prosthesis can be matched according to the patient's medullary cavity during surgery.

[0049] The sleeve 1 and the intramedullary needle-type femoral stem 2 are fixed by connecting the upper sleeve to enclose the anti-rotation and lowering the taper press fit. Specifically, the sleeve 1 and the intramedullary needle-type femoral stem 2 are connected and fixed in the following manner: the intramedullary needle-type femoral stem 2 is inserted into the sleeve 1, the femoral connector 4 is nested with the notch, and the sleeve 1 and the neck 5 are fixed by a taper press fit in the assembled fixed position to achieve vertical stability. The shape of the femoral connector 4 is similar to a rectangle, and it can be nested with the notch opened on the sleeve 1. The sleeve 1 forms a limit on the femoral connector 4, thereby improving the anti-rotation stability.

[0050] The above-mentioned metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis has the following beneficial effects:

[0051] (1) The present invention uses a sleeve made of metal material 3D printing and customized preparation, and matches it with the intramedullary pin-type femoral stem that can be mass-produced through taper, so as to achieve proximal biological fixation, and the locking nail holes and screws of the handle body at the distal end are used to achieve anti-rotation and prevent the prosthesis from sinking early, thereby further improving the stability of the prosthesis;

[0052] (2) The sleeve in the present invention is made of metal material by 3D printing and customization, and can match the shape of the medullary cavity of the proximal femur, solving the problem that the current artificial hip prosthesis does not match the proximal femoral fracture in the treatment of intertrochanteric fractures. The complete match increases the fixation strength of the prosthesis, and also solves the problem of reduced proximal femoral bone mass and decreased bone strength caused by distal fixation and stress shielding of the artificial prosthesis, thereby reducing complications;

[0053] The sleeve in the present invention uses 3D printing technology to match the proximal femoral medullary cavity. Due to the uncertainty of the fracture line and fracture position, the prosthesis in the prior art cannot be fixed at the proximal end, but the stability of the prosthesis is obtained by fixing the prosthesis at the distal end by lengthening the femoral stem. The initial replacement of the femoral stem prosthesis is a proximal matching fixation, and the fixation is not in accordance with the proximal femoral anatomical structure. Instead, the prosthesis is fixed after the medullary cavity is plasticized by a file. There is no anatomical match in morphology, so the initial prosthesis cannot be used in intertrochanteric fractures. The present invention uses a sleeve to match the shape of the proximal femoral medullary cavity, which increases the prosthesis fixation strength and solves the problems of the prosthesis in the prior art.

[0054] (3) The shoulder of the sleeve near the proximal femur is extended, which can be used to fix greater trochanter fractures, solve the problem of incomplete greater trochanter and difficulty in reconstructing femoral abduction function, and avoid the use of additional steel plates on the outside to increase costs, reduce costs, and alleviate the burden on patients. At the same time, the shoulder of the sleeve is provided with locking screw holes, making the prosthesis more expandable, and can provide a fixed interface for patients with greater trochanter fractures who need abductor muscle reconstruction, thereby achieving the purpose of restoring the patient's hip abduction function.

[0055] (4) Metal 3D printing technology can produce more advanced prosthesis coatings. The present invention facilitates bone ingrowth through the microporous structure design on the outer surface of the sleeve, so that the prosthesis and the bone have better initial stability, thereby achieving the purpose of biological fixation of bone ingrowth in the long term;

[0056] (5) The stem of the intramedullary pin-type femoral stem has an anterior bow to prevent the distal end of the femur from penetrating. At the same time, a locking nail hole is provided at the distal end of the stem, which not only increases the vertical and rotational stability of the prosthesis and prevents the prosthesis from rotating and sinking, but can also be used to fix periprosthetic fractures.

[0057] Since the medullary cavity diameters of different patients are different, for traditional prostheses, manufacturers need to design models of different thicknesses to match different patients to the greatest extent, so as to achieve the purpose of preventing the prosthesis from sinking and rotating; while the modular prosthesis of the present invention mainly relies on a customized 3D printed sleeve to achieve the goal of preventing the prosthesis from sinking and rotating, and no longer relies on the complete matching of the femoral stem and the medullary cavity. Therefore, the manufacturer can only produce a femoral stem of a fixed size that can adapt to all patients, which greatly reduces the production cost and simplifies the steps of implanting the femoral stem during surgery;

[0058] (6) The sleeve and the intramedullary pin-type femoral stem in the present invention are fixed by a taper press fit. This fixing method reduces the difficulty of manufacturing the femoral stem, and the function of the femoral stem prosthesis is changed from matching and fixing with the femur to connecting the sleeve and the femur. This new fixing method reduces the wear of the femur in traditional prosthesis replacement surgery and preserves the bone mass of the distal femur.

[0059] The metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis proposed in the present invention can be applied to the following clinical surgical treatments:

[0060] 1. Used in the treatment of intertrochanteric fractures in the elderly;

[0061] 2. Used in the treatment of benign and malignant tumors of the proximal femur;

[0062] 3. Used in proximal femoral orthopedic treatment;

[0063] 4. Used for revision of proximal femoral inclusive bone defect after hip replacement.

[0064] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis, characterized in that: It comprises a sleeve (1) and an intramedullary pin-type femoral stem (2); The sleeve (1) is made of metal material through 3D printing and customization. The outer surface of the sleeve (1) is a microporous structure and matches the shape of the medullary cavity of the proximal femur. The sleeve (1) is in the shape of a hollow cylinder as a whole. A notch is provided on the side wall near the upper end. The inner surface of the side wall near the lower end has a taper. A locking screw hole (3) for fixed connection with other fixing devices is provided on the shoulder opposite to the notch. The intramedullary needle-type femoral stem (2) comprises a femoral connector (4), a neck body (5) and a stem body (6) which are connected in sequence, the outer surface of the neck body (5) has a taper matching the sleeve (1), the stem body (6) has a front bow, and the distal end of the stem body (6) is provided with a locking nail hole (7) for fixing with the distal end of the femur; The sleeve (1) and the intramedullary needle-type femoral stem (2) are connected and fixed in the following manner: the intramedullary needle-type femoral stem (2) is inserted into the sleeve (1), the femoral connector (4) is nested and matched with the notch, and the sleeve (1) and the neck (5) are fixed by a taper press fit at the assembled and fixed position to achieve stability in the vertical direction; the microporous structure is a cubic structure, the porosity of the cubic structure is 70%, and the microporous diameter ranges from 200 to 400 μm; The metal material is titanium alloy.

2. The metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis according to claim 1 is characterized in that: The preparation process of the sleeve (1) comprises the following steps: Step 1: Obtain imaging data of the patient's proximal femur; Step 2: Produce a customized 3D digital model based on the imaging data; Step 3: Print and manufacture the sleeve using metal material according to the 3D digital model.

3. The metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis according to claim 1 is characterized in that: The micropore diameter is 320 μm.

4. The metal 3D printed customized sleeve assembly type femoral intramedullary pin prosthesis according to claim 1 or 2, characterized in that: The number of the locking screw holes (3) is 6, and the diameter of each locking screw hole (6) is 3.5 mm.

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