An experimental device for lower limb length changes during hip replacement surgery

Abstract

The present invention discloses an experimental device for lower limb length changes during hip replacement surgery, comprising: an artificial pelvis and an artificial lower limb, with an artificial hip joint disposed between the artificial pelvis and the artificial lower limb; the artificial hip joint comprising an artificial acetabulum, with a groove disposed on the bottom surface of the artificial acetabulum, the groove being matched with an artificial femoral head, and by adjusting the spatial position of the spherical center of the artificial femoral head, different hip rotation centers can be simulated; the artificial hip joint also comprising an artificial femoral stem, with the artificial lower limb being sleeved on the artificial femoral stem, and by adjusting the sleeve length of the artificial lower limb and the artificial femoral stem, different lower limb lengths can be simulated. The experimental device for lower limb length changes during hip replacement surgery is simple to operate and has good versatility. It can analyze in vitro the effects of artificial hip joints of different sizes and models on the patient's lower limb hip rotation center and lower limb length difference, and provide reference opinions for doctors to adjust the trial mold during surgery.

Description

Technical Field

[0001] The present invention relates to the technical field of analysis and testing platforms, and in particular to an experimental device for lower limb length changes during hip replacement surgery. Background Art

[0002] Total hip replacement is one of the most common orthopedic procedures, involving the use of an artificial hip prosthesis to replace a terminally diseased or damaged hip joint. The artificial hip joint typically consists of an acetabulum, liner, ball head, and femoral stem. These components vary in size and length, and the appropriate prosthesis must be selected based on the patient's actual bone age. Incorrect prosthesis selection can lead to complications such as lower limb length discrepancy, which alters the biomechanics of the lower limbs and lower back, and can cause a limping gait, compensatory pelvic tilt, and scoliosis after surgery.

[0003] Complications of lower limb length discrepancy are primarily caused by hip center of rotation deviation and femoral stem length abnormalities. Intraoperative testing and analysis of the impact of the prosthesis (acetabular cup, femoral head, and stem size and length) on the patient's hip center of rotation and lower limb length is risky, costly, and time-consuming, hindering surgeons' ability to adjust the trial model. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of the above-mentioned background technology and to provide an experimental device for lower limb length change during hip replacement surgery.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An experimental device for lower limb length changes during hip replacement surgery comprises: an artificial pelvis and an artificial lower limb, with an artificial hip joint arranged between the artificial pelvis and the artificial lower limb; the artificial hip joint comprises an artificial acetabulum, which engages with the artificial pelvis, and has a groove on the bottom surface of the artificial acetabulum, which is matched with an artificial femoral head, and different hip rotation centers can be simulated by adjusting the spatial position of the center of the sphere of the artificial femoral head; the artificial hip joint also comprises an artificial femoral stem, and the artificial lower limb is sleeved on the artificial femoral stem and fixed by bolts, and different lower limb lengths can be simulated by adjusting the sleeve length of the artificial lower limb and the artificial femoral stem.

[0007] As a further solution of the present invention: all outer surfaces of the artificial acetabular cup except the bottom surface are provided with gaskets, and the spatial position of the spherical center of the artificial femoral head can be adjusted by adjusting the number of the gaskets.

[0008] As a further solution of the present invention: the gasket includes a second gasket, a third gasket and a fourth gasket, the second gasket is arranged on the top surface of the artificial acetabular cup, and the number of the second gaskets is adjusted to adjust the height position of the center of the artificial femoral head; the third gasket is arranged on the left and right sides of the artificial acetabular cup, and the fourth gasket is arranged on the front and back sides, and the number of the third gasket and the fourth gasket is adjusted to adjust the planar position of the center of the artificial femoral head.

[0009] As a further solution of the present invention: the artificial femoral head is composed of a solid spherical segment and an internally threaded circular tube, and the end surface of the internally threaded circular tube is fixedly connected to the circular cross-section of the solid spherical segment.

[0010] As a further solution of the present invention: the artificial femoral head is threadedly connected to an artificial femoral head connecting rod, and the artificial femoral head connecting rod is a cylindrical rod. The upper part of the artificial femoral head connecting rod is provided with an external thread, and the lower part is a smooth curved surface.

[0011] As a further solution of the present invention: the artificial lower limb is connected to an artificial femoral stem via bolts, and the artificial femoral stem is provided with a connecting rod through hole that is compatible with the smooth curved surface of the lower part of the artificial femoral head connecting rod.

[0012] As a further solution of the present invention: the connecting rod through hole is a hole opened obliquely.

[0013] As a further solution of the present invention: the artificial femoral stem is provided with a limiting groove, and the limiting groove is provided with a limiting gasket.

[0014] As a further solution of the present invention: a plurality of first gaskets are provided between the limiting gasket and the artificial lower limb, and the sleeve length of the artificial lower limb and the artificial femoral stem can be adjusted by adjusting the number of the first gaskets.

[0015] As a further solution of the present invention: an artificial femoral head fixing cover is fixed to the bottom surface of the artificial acetabular cup by bolts, and the artificial femoral head fixing cover is provided with a through hole adapted to the artificial femoral head.

[0016] Beneficial effects of the present invention:

[0017] In the present invention, the experimental device for lower limb length change during hip replacement surgery is simple to operate and has good versatility. It can analyze in vitro the effects of artificial hip joints of different sizes and models on the patient's lower limb hip rotation center and lower limb length difference, and provide reference opinions for doctors to adjust the trial model during surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] Figure 1This is a schematic structural diagram of an experimental device for lower limb length changes during hip replacement surgery provided by the present invention;

[0020] Figure 2 This is a schematic cross-sectional view of a partial structure of an experimental device for lower limb length change during hip replacement surgery provided by the present invention;

[0021] Figure 3 yes Figure 2 Enlarged view of point A in the middle;

[0022] Figure 4 The present invention provides a schematic exploded view of the structure of a lower limb length change experimental device during hip replacement surgery.

[0023] In the figure: 1. artificial hip joint; 101. first gasket; 102. limiting gasket; 103. second gasket; 104. third gasket; 105. fourth gasket; 106. artificial femoral head fixation cover; 107. artificial acetabulum; 108. artificial femoral head; 109. artificial femoral head connecting rod; 110. connecting rod through hole; 111. artificial femoral stem; 112. limiting groove; 2. artificial pelvis; 201. artificial acetabulum; 3. artificial lower limb; 301. femoral stem groove. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] See also Figure 1 、 Figure 4 As shown, the present invention is an experimental device for lower limb length change during hip replacement surgery, comprising: an artificial pelvis 2 and an artificial lower limb 3, with an artificial hip joint 1 arranged between the artificial pelvis 2 and the artificial lower limb 3.

[0026] The artificial pelvis 2 is bilaterally symmetrical and includes two artificial acetabulums 201, which are also symmetrically distributed. The artificial acetabulums 201 are square grooves and have multiple screw holes for assembling the artificial hip joint 1. Two artificial hip joints 1 are also provided, which are distributed symmetrically. Accordingly, two artificial hip joints 1 are provided for each artificial hip joint 1, which are also distributed symmetrically.

[0027] See also Figure 2-Figure 3As shown, the artificial hip joint 1 includes an artificial acetabulum 107, which engages with the artificial pelvis 2, specifically within the artificial acetabulum 201. The bottom surface of the artificial acetabulum 107 has a hemispherical groove, which is matched with the artificial femoral head 108. By adjusting the spatial position of the center of the sphere of the artificial femoral head 108, different hip rotation centers can be simulated.

[0028] Specifically, all outer surfaces of the artificial acetabular cup 107 except the bottom surface are provided with gaskets, and the number of gaskets is adjusted to adjust the spatial position of the center of the artificial femoral head 108. The gaskets are all square plates with uniform thickness, and specifically include a second gasket 103, a third gasket 104 and a fourth gasket 105.

[0029] The second gasket 103 is set on the top surface of the artificial acetabular cup 107. The number of the second gaskets 103 is adjusted to adjust the height position of the center of the sphere of the artificial femoral head 108. The third gasket 104 is set on the left and right sides of the artificial acetabular cup 107, and the fourth gasket 105 is set on the front and back sides. The number of the third gasket 104 and the fourth gasket 105 is adjusted to adjust the plane position of the center of the sphere of the artificial femoral head 108. The bottom surface of the artificial acetabular cup 107 is fixed with an artificial femoral head fixing cover 106 by bolts. The artificial femoral head fixing cover 106 is a square plate with a through hole adapted to the artificial femoral head 108. The through hole is spherical, so that the artificial femoral head 108 can be assembled on the artificial acetabular cup 107.

[0030] The artificial femoral head 108 is composed of a solid spherical segment and an internally threaded circular tube, and the end face of the internally threaded circular tube is fixedly connected to the circular cross-section of the solid spherical segment. The spherical radius of the solid spherical segment of the artificial femoral head 108, the spherical radius of the hemispherical groove of the artificial acetabulum 107, and the spherical radius of the central spherical through hole of the artificial femoral head fixing cover 106 are identical, so that the solid spherical segment of the artificial femoral head 108 can rotate in the above-mentioned groove and through hole, and can simulate the movement of the human femoral head in the acetabulum.

[0031] Moreover, the artificial femoral head 108 is also threadedly connected to an artificial femoral head connecting rod 109. The artificial femoral head connecting rod 109 is a cylindrical rod. The upper part of the artificial femoral head connecting rod 109 is provided with an external thread, and the lower part is a smooth curved surface.

[0032] The artificial hip joint 1 also includes an artificial femoral stem 111. The artificial lower limb 3 is provided with a femoral stem slot 301 adapted to fit within the artificial femoral stem 111. The artificial lower limb 3 is sleeved within the artificial femoral stem 111, allowing the artificial femoral stem 111 to slide within the femoral stem slot 301. Once slid to a predetermined position, the artificial femoral stem 111 is secured to the artificial lower limb 3 via bolts. By adjusting the sleeve length between the artificial lower limb 3 and the artificial femoral stem 111, different lower limb lengths can be simulated.

[0033] Specifically, the artificial femoral stem 111 is provided with a connecting rod through hole 110 that is compatible with the smooth curved surface of the lower part of the artificial femoral head connecting rod 109. The connecting rod through hole 110 is an obliquely opened hole, which is convenient for adjusting the embedded position of the artificial femoral head connecting rod 109 in the connecting rod through hole 110.

[0034] See also Figure 3-Figure 4 As shown, the artificial femoral stem 111 is provided with a limiting groove 112, which is an annular groove structure. The limiting groove 112 is provided with a limiting gasket 102. The shape of the limiting gasket 102 is adapted to the limiting groove 112, so that the limiting gasket 102 can be inserted into the limiting groove 112 for fixation. After the limiting gasket 102 is inserted into the limiting groove 112, it will extend out of the surface of the artificial femoral stem 111 and serve as a limiting mark. A plurality of first gaskets 101 are arranged between the limiting gasket 102 and the artificial lower limb 3. The shape of the first gasket 101 is adapted to the artificial lower limb 3, which can avoid interfering with the insertion of the artificial femoral stem 111 into the femoral stem groove 301. The length of the sleeve between the artificial lower limb 3 and the artificial femoral stem 111 can be adjusted by adjusting the number of the first gaskets 101.

[0035] The inventors discovered that intraoperative testing and analysis of the effects of artificial hip prostheses on patients' hip rotation centers and lower limb lengths carries significant risks, is costly, and requires extended timelines, hindering physicians' ability to adjust trial models. Therefore, in vitro research on the effects of artificial hip joints on hip rotation centers and lower limb length is a pressing issue.

[0036] When using this hip replacement surgery lower limb length change experimental device, first select a hip rotation center and lower limb length as preoperative data.The second pad 103, the 3rd pad 104, the 4th pad 105 and artificial acetabulum 107 are assembled.Particularly, select several 3rd pads 104 and the 4th pad 105 to place the surrounding of artificial acetabulum 107, and use bolt that artificial acetabulum 107 is fastened in the artificial acetabulum 201.Again the internal threaded circular tube of artificial femoral head 108 is passed through the through hole in the center of artificial femoral head fixed cover 106, and use bolt that artificial femoral head fixed cover 106 is fixed on the artificial acetabulum 107 from four corners, at this moment, artificial femoral head fixed cover 106 fits with the contact surface of artificial acetabulum 107, the through hole of artificial femoral head fixed cover 106 cooperates with artificial acetabulum 107 grooves to form a spherical space, artificial femoral head 108 is locked in the spherical space, to ensure that artificial femoral head 108 both can rotate, can not produce loosening again. Then, the end of the artificial femoral head connecting rod 109 with an external thread is screwed into the internal threaded round tube of the artificial femoral head 108 and tightened. The other end of the artificial femoral head connecting rod 109 is inserted into the connecting rod through hole 110, and the artificial femoral head connecting rod 109 is pressed and fixed in the connecting rod through hole 110 by a bolt. Then, the limiting washer 102 is inserted into the limiting groove 112, and the lower end of the artificial femoral stem 111 is inserted into the femoral stem groove 301. One side of the limiting washer 102 is close to the top of the femoral stem groove 301, and the artificial femoral stem 111 is pressed and fixed in the femoral stem groove 301 by a bolt.

[0037] Rotate the artificial lower limb 3 and record the dynamic trajectory of a certain point on the artificial lower limb 3. The center position of the femoral head can be obtained by spatial spherical fitting, and the preoperative hip rotation center is recorded. The length from the preoperative rotation center to the capture point on the artificial lower limb 3 is temporarily recorded as the lower limb length.

[0038] The hip rotation center and the length of the lower limbs are quantitatively changed to analyze their effects on the change in the length of the lower limbs. Specifically, the number of the second gasket 103, the third gasket 104, and the fourth gasket 105 around the artificial acetabular cup 107 is adjusted, thereby changing the spatial position of the artificial acetabular cup 107. The thickness of the second gasket 103, the third gasket 104, and the fourth gasket 105 are uniform and the same. Then, the thickness of one gasket can be quantitatively calculated as the minimum amount of the spatial displacement of the artificial acetabular cup 107. The spatial position of the artificial acetabular cup 107 changes, and the spatial position of the center of the sphere of the artificial femoral head 108 changes accordingly, so the hip rotation center changes. The first gasket 101 is inserted between the limiting gasket 102 and the femoral stem groove 301. The number of the first gaskets 101 is several, and the thickness is the same and uniform. By controlling the number of the first gaskets 101, the change in the length of the lower limbs caused by the change in the length of the femoral stem of the artificial hip joint is simulated.

[0039] After quantitatively changing the number of first shims 101 and the number of second shims 103, third shims 104, and fourth shims 105 around the artificial acetabulum 107, the artificial lower limb 3 is shaken to determine the new spatial position of the hip rotation center and the lower limb length. By comparing the positions of the hip rotation center and lower limb length before and after the change in the number of shims, the spatial position difference of the hip rotation center and the lower limb length difference can be determined. Combined with the change in the number of shims, this device can assist physicians in analyzing the effects of the shift in the hip rotation center and the change in femoral stem prosthesis length on lower limb length (or human body posture) after total hip replacement. This device simulates in vitro the effects of different sizes and models of artificial hip joints (with different acetabulum, femoral head, and femoral stem prosthesis sizes and lengths) on the difference in lower limb length. This facilitates surgical guidance for physicians, provides reference for intraoperative adjustments to the trial model, and helps patients achieve equal lower limb length after surgery. This experimental device for lower limb length change during hip replacement surgery is simple to operate and highly versatile.

[0040] Working principle: The number of the second gasket 103, the third gasket 104, and the fourth gasket 105 around the artificial acetabular cup 107 is adjusted to thereby change the spatial position of the artificial acetabular cup 107. The thickness of the second gasket 103, the third gasket 104, and the fourth gasket 105 are uniform and the same. The thickness of one gasket can be quantified as the minimum amount of spatial displacement of the artificial acetabular cup 107. As the spatial position of the artificial acetabular cup 107 changes, the spatial position of the center of the sphere of the artificial femoral head 108 changes accordingly, thus changing the center of hip rotation. A first gasket 101 is inserted between the limiting gasket 102 and the femoral stem groove 301. The number of first gaskets 101 is several, and the thickness is uniform. By controlling the number of first gaskets 101, the change in lower limb length caused by the change in the length of the femoral stem of the artificial hip joint is simulated.

[0041] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. An experimental device for measuring the length change of lower limbs during hip replacement surgery, characterized in that: include: An artificial pelvis (2) and an artificial lower limb (3), wherein an artificial hip joint (1) is provided between the artificial pelvis (2) and the artificial lower limb (3); The artificial hip joint (1) includes an artificial acetabulum (107), the artificial acetabulum (107) is engaged with the artificial pelvis (2), a groove is provided on the bottom surface of the artificial acetabulum (107), and the groove is matched with an artificial femoral head (108), and different hip rotation centers are simulated by adjusting the spatial position of the center of the sphere of the artificial femoral head (108); The outer surfaces of the artificial acetabulum (107) except the bottom surface are all provided with gaskets, and the spatial position of the spherical center of the artificial femoral head (108) is adjusted by adjusting the number of the gaskets; The gasket comprises a second gasket (103), a third gasket (104) and a fourth gasket (105), wherein the second gasket (103) is arranged on the top surface of the artificial acetabular cup (107), and the number of the second gaskets (103) is adjusted to adjust the height position of the center of the artificial femoral head (108); The third gaskets (104) are provided on the left and right sides of the artificial acetabulum (107), and the fourth gaskets (105) are provided on the front and back sides. The number of the third gaskets (104) and the fourth gaskets (105) is adjusted to adjust the plane position of the center of the sphere of the artificial femoral head (108); The artificial hip joint (1) further comprises an artificial femoral stem (111), the artificial lower limb (3) is sleeved on the artificial femoral stem (111) and fixed by bolts, and different lower limb lengths can be simulated by adjusting the sleeve length of the artificial lower limb (3) and the artificial femoral stem (111); The artificial femoral stem (111) is provided with a limiting groove (112), the limiting groove (112) is provided with a limiting gasket (102), a plurality of first gaskets (101) are provided between the limiting gasket (102) and the artificial lower limb (3), and the sleeve length of the artificial lower limb (3) and the artificial femoral stem (111) is adjusted by adjusting the number of the first gaskets (101).

2. The experimental device for measuring the length change of lower limbs during hip replacement surgery according to claim 1, characterized in that: The artificial femoral head (108) is composed of a solid spherical segment and an internally threaded circular tube, and the end surface of the internally threaded circular tube is fixedly connected to the circular cross-section of the solid spherical segment.

3. The experimental device for measuring the length change of lower limbs during hip replacement surgery according to claim 1, characterized in that: The artificial femoral head (108) is threadedly connected to an artificial femoral head connecting rod (109), and the artificial femoral head connecting rod (109) is a cylindrical rod. The upper portion of the artificial femoral head connecting rod (109) is provided with an external thread, and the lower portion is a smooth curved surface.

4. The experimental device for measuring the length change of lower limbs during hip replacement surgery according to claim 3, characterized in that: The artificial lower limb (3) is connected to an artificial femoral stem (111) via a bolt, and the artificial femoral stem (111) is provided with a connecting rod through hole (110) adapted to the lower smooth curved surface of the artificial femoral head connecting rod (109).

5. The experimental device for measuring the length change of lower limbs during hip replacement surgery according to claim 4, characterized in that: The connecting rod through hole (110) is a hole opened obliquely.

6. The experimental device for measuring the length change of lower limbs during hip replacement surgery according to claim 1, characterized in that: An artificial femoral head fixing cover (106) is fixed to the bottom surface of the artificial acetabulum (107) via bolts, and the artificial femoral head fixing cover (106) is provided with a through hole adapted to the artificial femoral head (108).

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