CN104921796A - Tumor type knee joint prosthesis intramedullary needle - Google Patents

Abstract

The invention discloses an intramedullary nail for tumor type knee joint prosthesis, which comprises the lower section of the femoral bone marrow needle and the upper section of the femoral bone marrow needle inserted into the femoral medullary cavity during operation, and the lower section of the femoral bone marrow needle and the upper section of the femoral bone marrow needle are connected and the marrow The self-adaptive part of the inner needle has a certain degree of freedom of rotation; the self-adaptive part includes an self-adaptive support column arranged at the end of the upper section of the femoral bone marrow needle, and an inner pin hole opened on the self-adaptive support column; The outer pin hole that offers on the side wall of the femur, the self-adaptive support taper hole that the self-adaptive support column that offers at the end of femoral bone medullary needle lower section can insert; Also includes the pin that can insert outer pin hole and inner pin hole; Intramedullary nail of the present invention It can adapt to the physiological curvature of the femur that is obliquely upward and downward, and can better solve the mismatch between the femoral intramedullary nail and the femoral anatomical shape of the existing artificial knee joint prosthesis. question.

Description

A kind of intramedullary nail for tumor type knee joint prosthesis

technical field

The invention belongs to the field of biomechanics, and in particular relates to an intramedullary needle for a tumor type knee joint prosthesis.

Background technique

With the significant increase in the survival rate of malignant bone tumors and the success rate of limb salvage, patients have higher requirements for the function and long-term stability of long-segment prosthesis replacement. Tumor-type knee prosthesis replacement can complete functional reconstruction in a short period of time, but previous clinical studies have shown that the survival time of prostheses varies greatly. Although tumor-type knee prosthesis replacement can achieve functional reconstruction, anatomical reconstruction is difficult. Due to the large volume and long line of force of the tumor-type artificial knee prosthesis, theoretically the matching of the bone and the line of force of the prosthesis will affect its survival time. At the anatomical level, it is difficult for the prosthetic force line to conform to the physiological curvature of long bones, especially the sagittal force line of the femur. At present, there have been a lot of researches on the influence of coronal position and rotational force line of femoral tumor prosthesis on functional recovery and prosthesis service life after replacement. Doctors have high requirements for the alignment accuracy of the femur and the prosthesis in the coronal position, but the alignment accuracy of the femur and the prosthesis in the sagittal position is often ignored, resulting in poor sagittal alignment and affecting the sterility of the prosthesis. The main mechanical factors of loosening. The design of the traditional tumor-type knee prosthesis is too simple. Only the length of the limb and the width of the joint are reconstructed, which cannot ensure a good match between the force line of the prosthesis and the anatomical force line during the operation, which will affect the postoperative effect of the prosthesis.

Contents of the invention

In order to overcome the problems existing in the above-mentioned prior art, the object of the present invention is to provide an intramedullary needle for tumor-type knee joint prosthesis, which can be applied to reconstruction of residual limb function in tumor-type knee joint prosthesis replacement, and can better solve the problem of The problem of the mismatch between the physiological curvature of the lateral femur and the force line of the prosthesis, the intramedullary nail of the tumor-type prosthesis can better solve the problem of loosening and sinking of the prosthesis caused by the poor alignment of the prosthesis and the lateral force line of the femur. The problems of poor alignment of the lateral force line of the femur and inconformity with the physiological curvature of the lateral femur are better resolved.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A kind of intramedullary nail for tumor-type knee joint prosthesis, including the lower segment 1 of the femoral bone marrow needle and the upper segment 7 of the femoral bone marrow needle inserted into the femoral medullary cavity during operation, and connecting the lower segment 1 of the femoral bone marrow nail and the upper segment 7 of the femoral bone marrow needle to make the marrow The inner needle has an adaptive part with a certain degree of freedom of rotation; the adaptive part includes an adaptive support column 5 arranged at the end of the upper section 7 of the femoral bone marrow needle, and an inner pin hole 6 provided on the adaptive support column 5; The outer pin hole 2 provided on the end side wall of the lower part of the needle 1, the self-adaptive support taper hole 4 that can be inserted into the self-adaptive support column 5 opened at the end of the lower part of the femoral bone marrow needle 1; also includes the outer pin hole 2 and the inner pin that can be inserted Pin 3 for hole 6.

The diameter of the intramedullary nail is 8-13mm, the size of the adaptive part is small, and only a single pin is placed. At the same time, in order to ensure the tensile strength of the pin 3 and reduce the tensile strength of the self-adaptive support column 5 and the wall of the self-adaptive support taper hole 4 The weakening of the compressive strength, the cross-section of the pin 3 is oval.

The fit between the outer pin hole 2 and the pin 3 is an interference fit to prevent the pin from slipping along the axis of the pin 3 during implantation and use.

The cross-sectional dimension of the inner pin hole 6 is larger than that of the pin 3 to ensure that the existence of the pin 3 will not hinder the prosthesis self-adaptation process.

The self-adaptive support cone hole 4 has a taper, that is, the hole wall has an inclination angle, which is set to 5° in each direction, which allows the self-adaptive support column 5 and its upper part to be able to move relative to the self-adaptive support cone during the prosthesis implantation process. The hole 4 and its lower part have a certain degree of freedom of deviation, so as to better adapt to different shapes of the femoral medullary cavity; after implantation, the vacant part of the self-adaptive support cone hole 4 needs to be filled with bone cement to limit its relative movement.

Both the top end of the self-adaptive support column 5 and the bottom end of the self-adaptive support taper hole 4 adopt spherical surfaces, so that the two are in spherical contact.

Compared with the prior art, the present invention has the following advantages:

1. A movable part is inserted between the upper and lower parts of the intramedullary needle of the femoral component, so that the relative angle between the upper and lower parts can be changed within a certain range to adapt to different radians of the femoral medullary cavity; it makes up for the lack of radian of the existing prosthetic intramedullary needle Changes that cannot adapt to the individual differences in the curvature of the bone marrow cavity.

2. A spherical surface is used at the top of the self-adaptive support column 5 and the bottom of the self-adaptive support taper hole 4, so that the maximum contact area can still be ensured under different self-adaptive angles, and the pressure on the contact surface can be reduced when the pressure is applied. The stress and the shear stress of the pin 3 in turn reduce the probability of failure at this location.

3. The cross-sectional shape of the pin 3 is elliptical rather than the common circular shape, which increases the shear resistance of the pin 3 and reduces the pin holes to the upper self-adaptive support column 5 and the lower self-adaptive support taper hole 4 decrease in mechanical strength.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the intramedullary nail of the present invention.

Fig. 2 is a partial side sectional view of the adaptive component of the prosthesis, wherein Fig. 2b is an enlarged view of detail A in Fig. 2a.

Fig. 3 is a partial frontal cross-sectional view of the adaptive component of the prosthesis, wherein Fig. 3b is an enlarged view of detail B in Fig. 3a.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Other parts of the prosthesis connected with the design components are not considered as the content of this design, so they will not be described.

As shown in Fig. 1, Fig. 2 and Fig. 3, a kind of intramedullary needle of tumor-type knee joint prosthesis of the present invention comprises the femoral marrow needle lower section 1 and the femoral marrow needle upper section 7 inserted in the femoral medullary cavity during the operation and the femoral marrow needle The lower part 1 of the needle is connected with the upper part 7 of the femoral bone marrow needle and the self-adaptive part that makes the intramedullary needle have a certain degree of freedom of rotation; Adapt to the internal pin hole 6 provided on the support column 5; the external pin hole 2 provided on the end side wall of the lower segment of the femoral bone marrow needle 1, and the self-adaptive support column 5 opened at the end of the lower segment of the femoral bone marrow pin 1 can be inserted into the self-adaptive Support taper hole 4; also includes pin 3 that can be inserted into outer pin hole 2 and inner pin hole 6.

As a preferred embodiment of the present invention, the diameter of the intramedullary nail is only 8-13mm, the size of the adaptive part is small, and only a single pin is placed. 1. The weakening of the tensile and compressive strength of the wall of the self-adaptive support taper hole 4, the cross section of the pin 3 is elliptical.

As a preferred embodiment of the present invention, the fit between the outer pin hole 2 and the pin 3 is an interference fit, that is, the diameter of the outer pin hole 2 is slightly smaller than the diameter of the pin 3 to prevent the pin from moving along the axis of the pin 3 during implantation and use. slide.

As a preferred embodiment of the present invention, the cross-sectional dimension of the inner pin hole 6 is larger than that of the pin 3 to ensure that the existence of the pin 3 will not hinder the prosthesis self-adaptation process.

The self-adaptive support cone hole 4 has a taper, that is, the hole wall has an inclination angle, which is set to 5° in each direction, which allows the self-adaptive support column 5 and its upper part to be able to move relative to the self-adaptive support cone during the prosthesis implantation process. Hole 4 and its lower part have a certain degree of freedom of deviation and are set to 5° in each direction to better adapt to different shapes of the femoral medullary cavity; after implantation, the vacant part of the self-adaptive support taper hole 4 needs to be filled with bone cement to limit its relative motion.

In the present invention, the curvature of the femur is obtained by measuring the X-ray film with the PACS system. According to the physiological curvature of the patient's femur, the intramedullary needle can adjust the angles of each direction through the free axis during the operation, so as to adapt to the physiological curve of the human femur to the greatest extent. Require. Since the diameter of the pin is larger than that of the outer pin hole, the stability of the intramedullary nail at the free axis is guaranteed. After the intramedullary nail is implanted, the vacant part of the adaptive bearing taper hole is filled with bone cement to fix the intramedullary nail. This invention provides a prosthetic intramedullary nail that can better solve the mismatch between the physiological curvature of the lateral femur and the force line of the prosthesis, and is suitable for reconstructing the function of the residual limb in tumor-type knee prosthesis replacement. . The tumor-type prosthetic intramedullary nail can better solve the problem of loosening and sinking of the prosthesis caused by the poor alignment of the prosthesis and the lateral force line of the femur.

Claims (6)

1. a tumorous type knee-joint prosthesis intramedullary needle, is characterized in that: comprise in operation the femur bone marrow pin hypomere (1) and femur bone marrow pin epimere (7) that insert femur bone marrow intracavity and femur bone marrow pin hypomere (1) and femur bone marrow pin epimere (7) coupled together and make intramedullary needle have the self adaptation part of certain rotational freedom; Described self adaptation part comprises the self adaptation support column (5) being arranged on femur bone marrow pin epimere (7) end, the inner pinhole (6) that self adaptation support column (5) is offered; The outer pin-and-hole (2) that the end sidewalls of femur bone marrow pin hypomere (1) is offered, in self adaptation supporting taper hole (4) that the self adaptation support column (5) of the end opens of femur bone marrow pin hypomere (1) can insert; Also comprise the pin (3) that can insert outer pin-and-hole (2) and inner pinhole (6).

2. tumorous type knee-joint prosthesis intramedullary needle according to claim 1, it is characterized in that: described intramedullary needle diameter is 8-13mm, self adaptation portion size is little, only lay single pin, simultaneously in order to ensure the shear strength of pin (3) and the weakening reduced self adaptation support column (5), self adaptation supporting taper hole (4) hole wall Anti-pull-press intensity, the cross section of pin (3) is oval.

3. tumorous type knee-joint prosthesis intramedullary needle according to claim 1, it is characterized in that: described outer pin-and-hole (2) is interference fit with coordinating of pin (3), to prevent the slip of implanting and selling in use procedure along pin (3) axis direction.

4. tumorous type knee-joint prosthesis intramedullary needle according to claim 1, is characterized in that: the cross sectional dimensions of described inner pinhole (6) is greater than the cross sectional dimensions of pin (3) to ensure that the existence of selling (3) can not hinder prosthese adaptive process.

5. tumorous type knee-joint prosthesis intramedullary needle according to claim 1, it is characterized in that: described self adaptation supporting taper hole (4) with tapering and hole wall with angle of inclination, be set to all directions 5 °, allow self adaptation support column (5) and upper part thereof in Using prosthesis process relatively can have certain bias degree of freedom, better to adapt to different femur bone marrow cavity shapes in self adaptation supporting taper hole (4) and its underpart; After implanting, the rest of self adaptation supporting taper hole (4) need by Cement fixation to limit its relative motion.

6. tumorous type knee-joint prosthesis intramedullary needle according to claim 1, is characterized in that: the bottom of the top of described self adaptation support column (5) and self adaptation supporting taper hole (4) all have employed spherical surface, makes the two for sphere-contact.