A hemipelvic reconstruction prosthesis

Abstract

The application provides a half-pelvis reconstruction prosthesis, which comprises a iliac wing fixing part, a acetabular reconstruction part, a femoral stem, a acetabular reconstruction part, a pubic reconstruction part, a pubic symphysis, an ischium reconstruction part and a femoral stem. The pubic symphysis is provided with locking teeth on one side close to the pubic apex, the locking teeth are engaged with the locking teeth on the pubic apex, and the pubic apex and the pubic symphysis are fixedly connected through a first locking screw. The application solves the technical problem that the bone reference mark is lost after half-pelvis resection, and a small deviation of the implantation position causes abnormal hip joint eccentricity, soft tissue tension imbalance and gait compensation abnormality.

Description

Technical Field

[0001] This invention relates to the field of orthopedic implants, specifically to a hemipelvic reconstruction prosthesis. Background Technology

[0002] The pelvis is a vital bony structure connecting the trunk and lower limbs, playing a crucial role in supporting body weight, protecting pelvic organs, and transmitting mechanical loads. For hemipelvic defects caused by primary malignant tumors, metastatic tumors, or severe trauma, hemipelvic reconstruction prostheses are currently the primary means of limb salvage and functional reconstruction. An ideal hemipelvic reconstruction prosthesis should reliably restore the rotation center of the acetabulum, reconstruct the integrity of the pelvic ring, and provide long-term stable fixation. Existing hemipelvic reconstruction prostheses often employ customized metal implants, typically including an iliac wing fixation portion for fixing to the remaining iliac bone, an acetabular reconstruction portion, and a support component for connecting the pubis and ischium. However, such prostheses still face many challenges in long-term clinical application.

[0003] Regarding the connection structure and force transmission mechanism between the femoral stem and acetabular cup, existing hemipelvic reconstruction prostheses have particularly prominent design limitations. The femoral components are mostly designed as a single unit or fixed assembly, making continuous, stepless adjustment of key parameters such as femoral neck length, anteversion angle, and neck-shaft angle impossible during surgery. Furthermore, the lack of bony reference landmarks after hemipelvic resection means that rotation center reconstruction relies heavily on experience; even minor deviations in implantation position can cause abnormal hip joint misalignment, soft tissue tension imbalance, and gait compensation abnormalities, accelerating liner wear and prosthesis loosening. Even with some modular femoral stems allowing for the replacement of different taper connectors, adjustments are still limited to discrete dimensions, failing to meet the needs of fine-tuning. Moreover, the assembly interface adds additional risks of stress corrosion and fretting wear. Traditional femoral neck and stem lack an effective biomechanical buffering protection mechanism. Sudden impact loads generated by daily activities such as walking, sitting, and climbing stairs are transmitted almost without attenuation to the acetabular bone interface and the femoral stem medullary canal interface through the rigid femoral stem. This rigid connection causes the peak impact force to act directly on the prosthesis-bone junction area, inducing microstrain fatigue and stress-shielded bone resorption in the bone around the prosthesis. At the same time, it causes the contact surface between the acetabular cup and the liner, as well as the sliding surface between the ball head and the liner, to be subjected to abnormal impact pressure, accelerating the creep and wear of the high-molecular-weight polyethylene liner. Furthermore, the repeated impact effect between the distal femoral stem and the medullary canal wall will exacerbate the interfacial micromovement, promote the formation of a fibrous membrane and cause loosening. In cases of traumatic falls, it may even directly induce a fracture of the tip of the femoral stem. As a result, although the prosthesis can achieve physical reconstruction in the early stage, in the middle and long term, due to poor force transmission and lack of buffering and adjustment functions, loosening, pain, and even reconstruction failure frequently occur. Summary of the Invention

[0004] The purpose of this invention is to provide a hemipelvic reconstruction prosthesis to solve the technical problems caused by the lack of bony reference landmarks after hemipelvic resection, and the abnormal hip joint offset, soft tissue tension imbalance and gait compensation caused by slight deviations in the implantation position.

[0005] To address the aforementioned problems, this invention provides a hemipelvic reconstruction prosthesis, specifically comprising: an iliac wing fixation part, wherein an iliac wing fixation hole is provided on the iliac wing fixation part, and the iliac wing fixation part is fixedly connected to the autologous iliac bone through the fixation hole; an acetabular reconstruction part, comprising: an acetabular cup, the acetabular cup being fixed to the iliac wing fixation part, the acetabular cup having a multi-layer design, the outermost layer being a surface bone integration layer which is a porous tantalum metal layer with a porosity of 80% and an elastic modulus of 3-5 GPa, the middle layer being a filter layer with a porosity of 45%, and the innermost layer being a dense metal layer; a ball head, the ball head being fitted onto the femoral neck body; and an inner... The lining, made of high-molecular-weight polyethylene, is placed between the acetabular cup and the ball head; the pubic reconstruction section is fixedly connected to the iliac wing fixation section, and includes: the pubic roof, one side of which is connected to the iliac wing fixation section, and the other side of which is provided with a locking tooth; the pubic symphysis, the side of which near the pubic roof is provided with a locking tooth, which meshes with the aforementioned locking tooth on the pubic roof, and the pubic roof and the pubic symphysis are fixedly connected by a first locking screw; the ischium reconstruction section is fixedly connected to the iliac wing fixation section and the pubic reconstruction section; the femoral stem is composed of two parts: the femoral neck and the femoral stem body.

[0006] Furthermore, the femoral neck includes: a femoral neck base, one end of which is connected to a ball head, and a hollow buffer cavity is formed inside the femoral neck base; a femoral neck body, one end of which is connected to the aforementioned femoral neck base via an adjustment device, and the other end of which is fixedly provided with a connecting ball joint, the connecting ball joint being a hollow hemisphere, and the outer surface of the connecting ball joint being provided with multiple oblique receiving grooves;

[0007] Furthermore, the femoral stem body has a rotating ball joint at its top. The rotating ball joint is a hollow hemisphere, and multiple limiting claws are provided inside the rotating ball joint. The limiting claws are connected to the inclined receiving groove on the aforementioned femoral neck body.

[0008] Furthermore, the adjustment device includes: an expansion sleeve located on the outermost side and tightly connected to the aforementioned femoral neck base; a wedge block tightly attached to the expansion sleeve, with threads inside the wedge block; and a second locking screw with threads on one end surface that engage with the threads inside the aforementioned wedge block, and the other end of the second locking screw fixedly connected to the femoral neck body.

[0009] Furthermore, the iliac wing fixation part is an arc-shaped plate that matches the anatomical curvature of the outer plate of the iliac bone. Multiple iliac bone fixation holes are distributed along the edge of the arc-shaped plate, and the axial direction of some fixation holes is consistent with the direction of the principal stress of the iliac wing.

[0010] Furthermore, the locking teeth on the pubic symphysis and the locking teeth on the pubic symphysis are unidirectional ratchet structures, allowing the pubic symphysis to move unidirectionally toward the pubic symphysis and lock. The first locking screw passes through both the pubic symphysis and the pubic symphysis in a direction perpendicular to the meshing surface.

[0011] Furthermore, the outer surface of the femoral stem is provided with an osteointegration coating, which is a hydroxyapatite coating or a titanium bead sintered porous coating, and the distal end of the stem is conical or cylindrical to match the femoral medullary cavity.

[0012] Applying the technical solution of this invention, the iliac wing fixation part has an iliac bone fixation hole, through which the iliac wing fixation part is fixedly connected to the autologous iliac bone; the acetabular reconstruction part includes: an acetabular cup, which is fixed to the iliac wing fixation part. The acetabular cup has a multi-layer design, with the outermost layer being a surface bone integration layer, which is a porous tantalum metal layer with a porosity of 80% and an elastic modulus of 3-5 GPa; the middle layer is a filter layer with a porosity of 45%; and the innermost layer is a dense metal layer; a ball head, which is fitted onto the femoral neck body; and an inner liner, which is made of high molecular weight polyethylene. Ethylene material is placed between the acetabular cup and the ball head; pubic reconstruction part, which is fixedly connected to the iliac wing fixation part, the pubic reconstruction part includes: pubic roof, one side of the pubic roof is connected to the iliac wing fixation part, and the other side is provided with a locking tooth; pubic symphysis, the side of the pubic symphysis near the pubic roof is provided with a locking tooth, the locking tooth meshes with the aforementioned locking tooth on the pubic roof, the pubic roof and the pubic symphysis are fixedly connected by a first locking screw; ischium reconstruction part, which is fixedly connected to the iliac wing fixation part and the pubic reconstruction part; femoral stem, the femoral stem is composed of two parts: the femoral neck and the femoral stem body. The hemipelvic reconstruction prosthesis provided by this invention firstly achieves a gradient transition from a dense support layer to a high-porosity, low-elasticity surface bone integration layer through the structural design of the iliac wing fixation part and the multi-layer acetabular cup. The outer layer's approximately 80% interconnected porosity and 3-5 GPa elastic modulus can match the mechanical properties of the host's cancellous bone, effectively alleviating stress shielding effects and inducing three-dimensional bone ingrowth. The intermediate filter layer maintains structural strength while preventing wear particles from migrating to the bone interface, thereby achieving long-term biological stability fixation on the acetabular side. Simultaneously, the pubic roof and pubic symphysis form a reliable anti-retraction connection through interlocking locking teeth and the first locking screw, which is sufficient to resist the complex compressive, shear, and rotational forces in the pubic symphysis area, preventing fretting and screw breakage. The ischium reconstruction part, iliac wing fixation part, and pubic reconstruction part are mutually fixed to form a closed-loop pelvic ring, further improving the integrity of the pelvic ring and the load-bearing capacity in a sitting position.In the femoral stem assembly, the hollow buffer cavity within the femoral neck base can elastically deform to absorb energy during sudden impacts such as walking and sitting, preventing the peak value of the fissure force from being directly and rigidly transmitted to the bone-prosthesis interface and the sliding surface of the liner. This inhibits bone resorption around the prosthesis, fibrous membrane formation, and creep wear of the high-molecular-weight polyethylene liner. The adjustment device, through the cooperation of the expansion sleeve, wedge block, and second locking screw, allows for continuous and stepless adjustment of the femoral neck length during surgery, facilitating precise reconstruction of the hip joint rotation center even in the absence of a bony reference. The eccentricity, after adjustment, allows the wedge block to expand radially and lock, providing immediate mechanical stability. The oblique groove of the ball joint connecting the lower end of the femoral neck and the limiting claw of the rotating ball joint at the top of the femoral stem form a multi-directional fit and anti-rotation redundancy lock, which can allow limited adaptive angle compensation during operation and prevent rotational micro-movement loosening caused by multi-axis alternating load after operation. Its hemispherical hollow structure further enhances the overall buffer elasticity while ensuring connection strength, significantly improving the long-term survival rate and joint function reconstruction effect of the hemipelvic reconstruction prosthesis. Attached Figure Description

[0013] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0014] Figure 1 A partial view of the hemipelvis is shown;

[0015] Figure 2 A cross-sectional view of the acetabular cup is shown;

[0016] Figure 3 An enlarged view of the pubic bone reconstruction is shown;

[0017] Figure 4 A view of the femoral neck body is shown;

[0018] Figure 5 A view of the femoral stem body is shown;

[0019] The above-mentioned figures include the following reference numerals: 10, iliac wing fixation part; 101, iliac fixation hole; 20, acetabular reconstruction part; 201, surface bone integration layer; 202, filter layer; 203, dense metal layer; 204, ball head; 30, ischium reconstruction part; 40, pubic bone reconstruction part; 401, pubic top; 402, pubic symphysis; 403, locking tooth; 404, first locking screw; 501, femoral neck base; 502, buffer cavity; 503, femoral neck body; 504 connecting ball joint; 505, oblique retraction groove; 60, femoral stem body; 601, rotating ball joint; 602, limiting claw; A, adjustment device; A1, second locking screw; A2, wedge block; A3, expansion sleeve. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Any specific values ​​in all examples shown and discussed herein should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0023] like Figure 1 As shown: A hemipelvic reconstruction prosthesis includes: an iliac wing fixation part 10, an iliac bone fixation hole 101, the iliac wing fixation hole being used to fix the entire hemipelvic prosthesis onto the cross section of the human autologous iliac bone, an acetabular reconstruction part 20, the acetabular reconstruction part being used to place the acetabular cup, liner, ball head and femoral stem, the hemipelvic reconstruction prosthesis also includes an ischium reconstruction part and a pubic bone reconstruction part, since the pubic bone reconstruction part needs to fit with the pubic bone on the other side, during the reconstruction process, the pubic bone is divided into the pubic roof 401 and the pubic symphysis 402.

[0024] like Figure 2As shown in the cross-sectional view of the gradient biomimetic porous structure, the acetabular cup features a layered design. The outermost layer is the surface bone integration layer 201, with a porosity of 80% and an elastic modulus of 3-5 GPa. The middle layer is the filter layer 202, with a porosity of 45%. The innermost layer is a dense metal layer 203. This gradient biomimetic porous structure mimics the non-uniform mechanical properties of human bone, with a dense outer layer and a sparse inner layer. A spatial topological structure is constructed on the prosthesis contact surface using 3D printing technology. This allows the prosthesis to transition from a dense metal state in the core layer to a highly porous state in the surface layer, with the porosity typically increasing from 40% to 85%. This reduces the originally high elastic modulus of titanium alloy to a level similar to that of human cortical bone and even cancellous bone, solving the stress shielding problem caused by modulus mismatch and protecting the host bone from atrophy and necrosis due to insufficient stress. Clinically, this structure can effectively provide stability in the early postoperative period by increasing friction through the rough porous surface.

[0025] like Figure 3 As shown, the location of the pubic symphysis is difficult to control during pelvic reconstruction. In order to ensure that the reconstructed prosthesis fits the iliac bone and the pubic symphysis, the pubic reconstruction part 40 is improved in this invention. The pubic reconstruction part is divided into two parts: the pubic top 401 is closer to the iliac bone, and the pubic symphysis is farther away from the iliac bone. One side of the pubic top 401 is fixedly connected to the iliac bone, and the other side of the pubic top is provided with locking teeth 403. Locking teeth are also provided on the pubic symphysis. The locking teeth mesh with each other. During the operation, the prosthesis can be fitted with the autologous bone on the other side by rotating the pubic symphysis 402. After reaching the preset position, the entire pubic reconstruction part 40 is brought into the preset shape by the first locking screw 404.

[0026] like Figure 4 As shown, the femoral neck is equipped with an adjustment device A. Due to pelvic damage, the position of the femoral stem and acetabular cup will be affected during pelvic reconstruction. To improve the fit of the prosthesis, the length of the femoral neck can be adjusted intraoperatively using this device. The femoral neck is divided into two parts: the femoral neck base 501 is closer to the acetabular cup, and a buffer cavity 502 is provided inside the femoral neck; the side of the femoral neck away from the acetabular cup is the femoral neck body 503. The femoral neck base 501 and the femoral neck body 503 are connected by the adjustment device A. The joint device A is located inside the femoral neck base and consists of a second locking screw A1, a wedge block A2, and an expansion sleeve A3. After the prosthesis is implanted, the second locking screw A1 can be rotated to move it longitudinally. Under the action of the wedge block A2, the expansion sleeve A3 is compressed, thereby applying pressure to the inside to fix the second locking screw. When the preset length is reached, the rotation of the second locking screw is stopped. Under the action of the wedge block A2 and the expansion sleeve A3, the final length of the femoral neck is adjusted to a suitable position.

[0027] like Figure 5 As shown, since the position of the entire hip joint prosthesis is changed during the reconstruction of the hemipelvic prosthesis, in order to improve the compatibility between the prosthesis and the autologous bone and ensure the stability of the prosthesis, angle adjustment can be achieved between the femoral stem body 60 and the femoral neck body 503. In this invention, the side of the femoral neck closest to the femoral stem body is set as a hemispherical connecting ball joint 504. The connecting ball joint 504 is fixedly connected to the femoral neck body 503. Multiple oblique receiving grooves 505 are provided around the connecting ball joint. The top of the femoral stem body 60... The device is equipped with a motion ball joint 601, which is fixedly connected to the femoral stem body 60. Multiple limiting claws 602, made of elastic material, are located on the inner side of the motion ball joint and are locked into the oblique retraction groove 505. During surgery, the connecting ball joint 504 can be separated from the motion ball joint 601. Then, the femoral stem body 60 is rotated to a preset position, and the motion ball joint 601 is pressed firmly onto the connecting ball joint 504. Under the pressure, the limiting claws 602 tighten inward and are locked in the oblique retraction groove 505. This allows for adjustment of the femoral stem angle.

[0028] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0029] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0030] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hemipelvic reconstruction prosthesis, characterized in that, include: The iliac wing fixation part is provided with an iliac bone fixation hole, and the iliac wing fixation part is fixedly connected to the autologous iliac bone through the fixation hole; The acetabular reconstruction unit includes: an acetabular cup, which is fixed to the aforementioned iliac wing fixation unit. The acetabular cup has a multi-layer design, with the outermost layer being a porous tantalum metal surface bone integration layer with a porosity of 80% and an elastic modulus of 3-5 GPa; the middle layer being a filter layer with a porosity of 45%; and the innermost layer being a dense metal layer; a ball head, which is fitted onto the femoral neck; and an inner liner, which is made of high-molecular-weight polyethylene material and placed between the aforementioned acetabular cup and the ball head. The pubic bone reconstruction part is fixedly connected to the iliac wing fixation part. The pubic bone reconstruction part includes: a pubic bone top, one side of which is connected to the iliac wing fixation part, and a locking tooth is provided on the other side; a pubic symphysis, the side of which near the pubic bone top is provided with a locking tooth, the locking tooth engaging with the aforementioned locking tooth on the pubic bone top, and the pubic bone top and the pubic symphysis are fixedly connected by a first locking screw. The ischium reconstruction section is fixedly connected to the iliac wing fixation section and the pubic bone reconstruction section. The femoral stem comprises a femoral neck and a femoral stem body. The femoral neck includes: a femoral neck base, one end of which is connected to a ball head, and the interior of the femoral neck base forms a hollow buffer cavity; and a femoral neck body, one end of which is connected to the aforementioned femoral neck base via an adjustment device, and the other end of which is fixedly provided with a connecting ball joint, which is a hollow hemisphere, and its outer surface is provided with multiple oblique receiving grooves. The adjustment device includes: an expansion sleeve, located on the outermost side and connected to the front... The femoral neck base is tightly connected; a wedge-shaped block is tightly fitted to the expansion sleeve, and the wedge-shaped block has internal threads; a second locking screw has threads on one end that engage with the threads in the wedge-shaped block, and the other end of the second locking screw is fixedly connected to the femoral neck body. By rotating the second locking screw, the second locking screw moves longitudinally, and under the action of the wedge-shaped block, the expansion sleeve is squeezed, thereby applying inward pressure to fix the second locking screw. After adjustment, the wedge-shaped block expands radially and locks.

2. The hemipelvic reconstruction prosthesis according to claim 1, characterized in that, The femoral stem has a rotating ball joint at its top. The rotating ball joint is a hollow hemisphere. Multiple limiting claws are provided inside the rotating ball joint. The limiting claws are engaged with the oblique receiving groove on the aforementioned femoral neck.

3. The hemipelvic reconstruction prosthesis according to claim 1, characterized in that, The iliac wing fixation part is an arc-shaped plate that matches the anatomical curvature of the outer plate of the iliac bone. Multiple iliac bone fixation holes are distributed along the edge of the arc-shaped plate, and the axial direction of some fixation holes is consistent with the principal stress direction of the iliac wing.

4. The hemipelvic reconstruction prosthesis according to claim 1, characterized in that, The locking teeth on the top of the pubic bone and the locking teeth on the pubic symphysis are unidirectional ratchet structures, which allow the pubic symphysis to move unidirectionally toward the top of the pubic bone and lock. The first locking screw passes through the pubic symphysis and the top of the pubic bone simultaneously in a direction perpendicular to the meshing surface of the teeth.

5. The hemipelvic reconstruction prosthesis according to claim 1, characterized in that, The outer surface of the femoral stem is provided with an osteointegration coating, which is a hydroxyapatite coating or a titanium bead sintered porous coating. The distal end of the stem is conical or cylindrical to match the femoral medullary cavity.

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