CN116211550A

CN116211550A - Low elastic modulus assembled femoral stem for reconstruction of serious bone defect of femur

Info

Publication number: CN116211550A
Application number: CN202310358060.XA
Authority: CN
Inventors: 黄勇; 周一新; 邵宏翊; 杨德金
Original assignee: Beijing Jishuitan Hospital
Current assignee: Beijing Jishuitan Hospital
Priority date: 2023-04-06
Filing date: 2023-04-06
Publication date: 2023-06-06

Abstract

The invention relates to a low elastic modulus assembled femoral stem for reconstruction of a severe bone defect of a femur, comprising: the device comprises a proximal sleeve, a distal sleeve and a distal sleeve, wherein the proximal sleeve comprises a sleeve body and a femoral head connecting part arranged on the sleeve body, and a female cone is further arranged on the sleeve body; the distal femur stem comprises an inner core body and an outer sleeve body sleeved outside the inner core body, wherein a male cone matched with the female cone is arranged at the proximal end of the inner core body, and the male cone is exposed outside the outer sleeve body; the proximal sleeve is detachably connected with the distal femoral stem. The femoral stem prosthesis is provided with the stem body with two materials of external softness and internal hardness, and the outer sleeve body is a softer prosthesis, so that the elastic modulus is lower, the contact area between the femoral stem and a bone bed can be increased, the stress concentration can be avoided, the stress conduction area of the bone bed can be increased, complications such as fracture during operation, postoperative stress shielding and prosthesis sinking are reduced, and the initial stability of the femoral stem is increased.

Description

Low elastic modulus assembled femoral stem for reconstruction of serious bone defect of femur

Technical Field

The invention relates to a low elastic modulus assembled femoral stem for reconstruction of serious femoral bone defects, and belongs to the technical field of medical appliances.

Background

The number of artificial total hip revision operations in the united states in 2005 is 40800, and it is expected that the number of artificial total hip revision operations in the united states in 2030 will be 137% higher than in 2005, up to 96700, and the number of artificial total hip revision operations in China has been rapidly increased over the past 20 years, though the number of artificial hip revision operations in China is late in comparison with the united states. The femoral side often faces various degrees of bone defects in artificial total hip revision due to severe osteolysis, stress shielding, peri-prosthetic infection, multiple surgical history, osteoporosis, iatrogenic bone defects caused by perforation or windowing when taking out the original prosthesis or residual bone cement, etc., wherein the femoral side PaproskyIV type bone defects are very tricky to handle. Current common treatments include cement stem fixation (cement stem technology), assembled or unassembled distal fixation tapered ridged titanium alloy stems, compression bone implants, allograft bone prosthesis composites, and tumor prosthesis replacement. However, for those IV type bone defects that the thighbone cortex is thin, the medullary cavity is wide and the isthmus can be used for fixation, the common treatment methods have the defects of prosthesis fixation failure, prosthesis sinking, long operation time, high risk of fracture in operation, poor operation function, high absorption and infection risk caused by abnormal bone integration failure and the like, the pain and the risk are brought to patients needing femur side repair, most of the treatment methods are foreign import prostheses, the treatment methods are expensive, and the great consumption of medical and health resources and the increase of medical cost are caused.

Disclosure of Invention

Aiming at the technical problems, the invention provides a low elastic modulus assembled femoral stem for reconstructing serious bone defects of femur, in particular to a snowshoe type assembled femoral stem for reconstructing serious bone defects of femur in artificial hip joint revision.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

a low modulus of elasticity assembled femoral stem for reconstruction of a severe bone defect in a femur, comprising:

the device comprises a proximal sleeve, a distal sleeve and a distal sleeve, wherein the proximal sleeve comprises a sleeve body and a femoral head connecting part arranged on the sleeve body, and a female cone is further arranged on the sleeve body;

the distal femur stem comprises an inner core body and an outer sleeve body sleeved outside the inner core body, and a male cone matched with the female cone is arranged at the proximal end of the distal femur stem;

the proximal sleeve is detachably connected with the distal femoral stem.

The low elastic modulus combined femoral stem for reconstruction of serious bone defect of femur is preferably provided with a longitudinal ridge on the outer wall surface of the outer sleeve body.

The low elastic modulus assembled femoral stem for reconstruction of serious bone defect of femur preferably further comprises a screw, and the male cone is provided with a screw hole for accommodating the screw.

The low elastic modulus component femoral stem for reconstruction of a severe bone defect of a femur, preferably the screw and the inner core body are located on the same axis.

The low elastic modulus assembled femoral stem for reconstruction of serious bone defect of femur, preferably, the proximal sleeve is cylindrical as a whole, and the taper of the female cone is the same as the taper of the male cone.

The low elastic modulus assembled femoral stem for reconstruction of serious bone defect of femur is preferably conical, the taper is 1.5-6 degrees, and the diameter is 1 cm-4.5 cm.

The low elastic modulus assembled femoral stem for reconstruction of serious bone defect of femur is preferably cylindrical, the diameter of the inner core body is 6 mm-12 mm, and the length of the inner core body is 17 cm-42 cm.

The low elastic modulus combined femoral stem for reconstruction of serious bone defect of femur preferably has the length of 4 cm-8 cm and the taper of 12/14.

The low elastic modulus assembled femoral stem for reconstruction of serious bone defect of femur preferably has a porous coating layer coated on the outer wall surface of the outer sleeve 202, the length of the coating layer is 10 cm-38 cm, and the thickness of the coating layer is 50 um-2 mm.

The low elastic modulus assembled femoral stem for reconstructing the serious bone defect of the femur is characterized in that preferably, the longitudinal ridges are 6-12 ridges which are longitudinally arranged and uniformly arranged on the outer wall of the outer sleeve body at intervals, the height is 0.5-2 mm, and the width is 1-2 mm.

Due to the adoption of the technical scheme, the invention has the following advantages:

1. the femoral stem prosthesis is arranged into the stem body with two materials of external softness and internal hardness, and because the outer sleeve body is a softer prosthesis, the elastic modulus is lower, and the softer, easy-to-deform and thicker conical ridged femoral stem is driven into the softer PaproskyIV bone defect femur, the contact area of the femoral stem and the bone bed can be increased, the stress concentration can be avoided, the stress conduction area of the bone bed can be increased, complications such as fracture during operation, stress shielding after operation, prosthesis sinking and the like are reduced, and the initial stability of the femoral stem is increased.

2. The outer sleeve body is provided with the longitudinal ridges, and the protruding longitudinal ridges can be wedged into the cortical bone on the inner surface of the femur when the femur stem is driven into the femur medullary cavity, so that the rotation stability is provided, and the initial fixation of the femur stem is facilitated to be enhanced.

3. The outer sleeve body adopts the PEEK composite material, the mechanical properties of the outer sleeve body are similar to those of bone tissues, the deformation amounts of the outer sleeve body and the bone tissues are similar when stress is loaded, the stress bearing area is relatively large, the axial shearing stress resistance and the rotation resistance of the femoral stem are improved, the initial stability of the prosthesis is improved, and a foundation is provided for the bone ingrowth of the surface of the prosthesis, so that the long-term biological fixation is facilitated.

Drawings

FIG. 1 is a schematic view of a proximal sleeve according to one embodiment of the present invention;

FIG. 2 is a schematic view of a distal femoral stem provided in this embodiment of the present invention;

FIG. 3 is a cross-sectional view of FIG. 2;

FIG. 4 is a schematic view of the overall assembly femoral stem for reconstruction of a severe bone defect in a femur according to the present invention;

the figures are marked as follows:

1-a proximal sleeve, 101-a sleeve body, 102-a female cone, 103-a femoral head connection part;

2-distal femoral stem;

201-an inner core body; 202-an outer sleeve, 2021-longitudinal ridges; 203-male cone; 204-coating;

3-screw.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are intended to be within the scope of the present disclosure.

Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The terms "first," "second," "third," "fourth," and the like as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

The elastic modulus of the existing traditional cobalt-chromium-molybdenum or titanium alloy femoral stem prosthesis is far more than that of bone (the cobalt-chromium-molybdenum alloy is 220GPa, the titanium alloy is 110GPa, and the cortical bone is only 18 GPa), so that a series of complications such as stress concentration, stress shielding, small effective fixing area, unstable prosthesis fixation and the like are generated. Considering that the PaproskyIV bone defect femur has weak bone quality, the elastic modulus is lower than that of a normal femur, and the bone quality is softer. The present application incorporates the "snowshoe effect" in daily life, namely: on softer snowfields, larger snowshoes are worn, increasing the contact area, so that snowshoes with larger contact areas are less likely to sink into soft snowfields. This application designs into softer prosthesis with the femoral stem prosthesis, and modulus of elasticity is lower promptly, with softer, easy deformation, the thick toper takes spine femoral stem to throw into soft PaproskyIV bone defect femur, increases the area of contact of femoral stem and bone bed, can avoid stress concentration and increase bone bed stress conduction area, reduces complications such as fracture in the art, postoperative stress shelter from and prosthetic subsidence, increases the initial stability of femoral stem.

The technical scheme of the invention is described in detail below with reference to the accompanying drawings.

1-3, which are schematic views of a low elastic modulus assembled femoral stem for reconstruction of serious bone defect of femur according to the present invention, including a proximal sleeve 1, a distal femoral stem body 2 and a screw 3 which are designed separately, wherein the proximal sleeve 1 includes a sleeve body 101 and a femoral head connecting portion 103 provided on the sleeve body 101, and a female cone 102 is further provided on the sleeve body 101; the distal femur stem 2 includes an inner core 201 and an outer sleeve 202 sleeved outside the inner core 201, and a male cone 203 adapted to the female cone 102 is provided at the proximal end of the inner core 201. The distal femur handle body 2 and the proximal sleeve 1 are connected through taper locking, and simultaneously the distal and proximal ends are locked by the screw 3, so that the distal and proximal taper locking failure is prevented.

Further, in the actual process of performing the artificial total hip revision, the screw 3 and the inner core 201 are located on the same axis, so that the stability of assembling the femoral stem can be ensured. More preferably, the screw has a length of between 5cm and 8cm, a diameter of 5mm, a threaded portion at the screw tip and a length of 1cm, and a screw tail cap portion of hexagonal design.

In some preferred embodiments of the invention, the proximal sleeve 1 is cylindrical, has a diameter of between 18mm and 35mm and a length of between 70mm and 100mm, and the distal portion has a tapered female taper 102 (taper hole), the female taper 102 having a depth of 5cm and the proximal male taper 203 of the distal femoral stem 2 having the same taper lock.

In some preferred embodiments of the present invention, the core body 201 is made of cobalt chromium molybdenum alloy, the core body 201 is cylindrical, has an elastic modulus of 220GPa, a diameter of between 6mm and 12mm, and a length of between 17cm and 42cm.

Further, the whole of the distal femur handle body 2 is conical, the taper is 1.5-4 degrees, the diameter is 1 cm-4.5 cm, and the whole length of the distal femur handle body 2 is between 12cm and 35 cm. More preferably, the outer sleeve 202 has a thickness of between 2mm and 16.5mm and a length of between 12cm and 35cm at the middle section of the distal femoral stem 2, and is generally tapered with a taper of between 1.5 ° and 4 °.

Further, the male taper 203 has a length of between 4cm and 8cm and a taper of 12/14. The male cone 203 is provided with a threaded hole, and the threaded hole is internally provided with 1cm of internal surface threads, so that the male cone can be locked with a screw.

In some preferred embodiments of the present invention, the outer sleeve 202 is made of Polyetheretherketone (PEEK), and since the PEEK composite prosthesis has similar mechanical properties to bone tissue, the deformation amounts of the PEEK composite prosthesis and the PEEK composite prosthesis are similar when loaded with stress, the stress bearing area is relatively large, the axial shear stress resistance and the rotation resistance of the femoral stem are increased, the initial stability of the prosthesis is increased, and a foundation is provided for bone ingrowth of the prosthesis, thereby helping to obtain long-term biological fixation.

Further, the outer wall surface of the PEEK outer sleeve 202 is provided with a porous coating structure, which can be 3D printed titanium alloy porous, or a titanium slurry plasma coating and a surface covering hydroxyapatite coating or a porous tantalum metal coating, the coating part is 1cm to 6cm long, and the coating thickness is 50um to 2mm. The coating is uniformly provided with 6 to 12 protruding longitudinal ridges 2021 at intervals, the height of the protruding longitudinal ridges 2021 is between 0.5mm and 2mm, the heights of the protruding longitudinal ridges 2021 can be uniform and uniform, the protruding longitudinal ridges 2021 can also be distributed at different heights, and the protruding longitudinal ridges 2021 can be wedged into the cortical bone of the inner surface of the femur when the femoral stem is driven into the femoral medullary cavity, so that the rotation stability is provided, and the initial fixation of the femoral stem is enhanced.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low modulus of elasticity assembled femoral stem for reconstruction of a severe bone defect in a femur, comprising:

the device comprises a proximal sleeve (1), wherein the proximal sleeve (1) comprises a sleeve body (101) and a femoral head connecting part (103) arranged on the sleeve body (101), and a female cone (102) is further arranged on the sleeve body (101);

the distal femur stem body (2), the distal femur stem body (2) comprises an inner core body (201) and an outer sleeve body (202) sleeved outside the inner core body (201), and a male cone (203) matched with the female cone (102) is arranged at the proximal end of the distal femur stem body (2);

the proximal sleeve (1) is detachably connected with the distal femur handle body (2).

2. The low elastic modulus assembled femoral stem for reconstruction of severe bone defects in the femur according to claim 1, wherein a longitudinal ridge (2021) is provided on the outer wall surface of the outer casing (202).

3. The low elastic modulus assembled femoral stem for reconstruction of severe bone defects in the femur according to claim 1, further comprising a screw (3), said male taper (203) being provided with a screw hole for receiving said screw (3).

4. A low elastic modulus assembled femoral stem for reconstruction of severe bone defects of the femur according to claim 3, characterized in that the screw (3) is co-axially located with the inner core (201).

5. The low elastic modulus assembled femoral stem for reconstruction of severe bone defects in the femur according to claim 1, characterized in that the proximal sleeve (1) is entirely cylindrical, the female taper (102) has the same taper as the male taper (203).

6. The low elastic modulus assembled femoral stem for reconstruction of severe femoral bone defects according to claim 1, wherein the distal femoral stem body (2) is conical overall, with a taper of 1.5 ° to 6 ° and a diameter of 1cm to 4.5cm.

7. The low elastic modulus assembled femoral stem for reconstruction of severe bone defects in the femur according to claim 1, wherein the inner core (201) is generally cylindrical, having a diameter of 6mm to 12mm and a length of 17cm to 42cm.

8. The low elastic modulus assembled femoral stem for reconstruction of severe bone defects in the femur according to claim 1, wherein the male taper (203) is 4cm to 8cm in length and the taper is 12/14.

9. The low elastic modulus assembled femoral stem for reconstruction of severe bone defects of femur according to claim 1, wherein the outer wall surface of the outer casing (202) is coated with a porous coating (204), the length of the coating (204) is 10 cm-38 cm, and the thickness of the coating (204) is 50 um-2 mm.

10. The low elastic modulus assembled femoral stem for reconstruction of severe bone defects in femur according to claim 2, wherein the longitudinal ridges (2021) are 6 to 12 longitudinally arranged ridges uniformly spaced on the outer wall of the outer casing (202), having a height of 0.5mm to 2mm and a width of 1mm to 2mm.