A measuring component for determining the model of a femoral head prosthesis

Abstract

A measuring assembly for determining the model of a femoral head prosthesis comprises a first measuring device and a second measuring device, the first measuring device comprising a first assembly fixed to the upper edge of the acetabulum and provided with a first scale and a second assembly fixed to the lesser trochanter of the femur, the second measuring device being provided with an opening, a sliding portion being provided in the opening, the sliding portion being provided with a connecting groove for connecting a femoral stem prosthesis, the sliding portion being further provided with a second scale and a second rack, and the second measuring device being provided with a screw rod that cooperates with the second rack rod for transmission; the present invention drives the sliding portion to move the femoral stem prosthesis by driving the screw rod, and at the same time the first assembly slides out of the second assembly, when the first scale is equal to the normal value from the upper edge of the acetabulum to the lesser trochanter of the femur, the corresponding second scale value is the difference in radial dimension of the femoral head prosthesis during surgery relative to a standard femoral head prosthesis, thereby determining the model selection of the femoral head prosthesis during artificial hip replacement surgery and solving the problem of unequal length of the lower limbs after total hip replacement surgery.

Description

Technical Field

[0001] The present invention relates to the technical field of medical instruments, and in particular to a measuring component for determining the model of a femoral head prosthesis. Background Art

[0002] Total hip arthroplasty (THA) is an effective clinical procedure for treating severe hip pain, deformity, and dysfunction. It can significantly reduce pain in patients with advanced hip arthritis and is known as the "forgotten surgery." It has been widely performed both domestically and internationally. However, leg length discrepancy is a major complication after THA, potentially leading to altered hip biomechanics, abnormal gait, low back pain, sciatica, instability, and early implant loosening. Leg length discrepancy is a major cause of patient dissatisfaction after THA and a common cause of orthopedic litigation.

[0003] For years, lower limb length discrepancy has been a hotly debated issue among researchers and clinicians, and numerous studies have explored how to address this issue postoperatively. However, the length of the prosthesis used has typically been determined by intraoperatively measuring the distance between the greater trochanter and the acetabulum, without considering the radial dimensional differences of the femoral head prosthesis. Without practical measurement tools, the specific model and length of the femoral head prosthesis used has largely been determined by the surgeon's clinical experience, resulting in poor accuracy. Summary of the Invention

[0004] In view of the shortcomings of the background technology, the purpose of the present invention is to provide a measurement component for determining the model of a femoral head prosthesis.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A measuring assembly for determining the model of a femoral head prosthesis, comprising:

[0007] A first measuring device includes a first component fixed to the upper edge of the acetabulum and a second component fixed to the lesser trochanter of the femur, the first component slidably fitted within the second component, one of the first component and the second component being provided with a knob portion, the other being provided with a first rack that is transmission-engaged with the knob portion, and one end of the first component that slidably fits within the second component being further provided with a first scale, the first scale being used to display the distance from the upper edge of the acetabulum to the lesser trochanter of the femur;

[0008] A second measuring device, wherein the second measuring device is provided with an opening, a sliding portion is provided in the opening which slides along the axis of the opening, the sliding portion is provided with a connecting groove for connecting a femoral stem prosthesis, the sliding portion is further provided with a second scale and a second rack, the second scale includes a plurality of negative scales, a zero scale and a plurality of positive scales, the zero scale is flush with the end face of the connecting groove, the largest positive scale is flush with the bottom end face of the connecting groove, and the second measuring device is further provided with a screw rod which cooperates with the second rack gear;

[0009] The first component and the second component are fixed to the upper edge of the acetabulum and the lesser trochanter of the femur, respectively. The second measuring device is placed between the upper edge of the acetabulum and the lesser trochanter of the femur and is connected to the femoral stem prosthesis. The sliding part is driven by the screw to move the femoral stem prosthesis, and at the same time, the first component slides out of the second component. When the first scale is equal to the normal value from the upper edge of the acetabulum to the lesser trochanter of the femur, the corresponding second scale value is the difference in radial size of the femoral head prosthesis to be used during the operation relative to the standard femoral head prosthesis.

[0010] Furthermore, the first component includes a first through hole and a first measuring part, a first fixed arm is connected between the first through hole and the first measuring part, and the second component includes a second through hole and a second measuring part, a second fixed arm is connected between the second through hole and the second measuring part; the first measuring part is slidably sleeved in the second measuring part, one of the first measuring part and the second measuring part is provided with the knob part, and the other is provided with the first rack that is transmission-matched with the knob part, and the first measuring part is provided with the first scale.

[0011] Furthermore, the first measuring part is provided with the first rack, and the second measuring part is provided with the knob part.

[0012] Furthermore, the knob portion includes a knob body and a gear. The knob body is inserted into the second measuring portion. The gear is disposed inside the second measuring portion and is in transmission cooperation with the first measuring portion.

[0013] Furthermore, the first scale is the first rack.

[0014] Furthermore, the first rack includes a plurality of engaging teeth, and the width of each engaging tooth is 1-4 mm.

[0015] Furthermore, a slide groove is provided in the second measuring device, and the sliding part is slidably connected to the slide groove.

[0016] Furthermore, the sliding portion includes a shaft portion, a neck portion and the connecting groove from bottom to top, the shaft portion is provided with the second scale and the second rack, the neck portion is slidably connected to the sliding groove, and the connecting groove is provided outside the sliding groove.

[0017] Furthermore, the smallest negative scale is flush with the end surface of the shaft portion, and the measurement range of the second scale is -10 to +10 mm.

[0018] Furthermore, the second measuring device is provided with a notch for facilitating the movement of the screw.

[0019] Furthermore, the second knob is provided with a scale inside the femoral head prosthesis.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention proposes a measuring component for determining the model of a femoral head prosthesis. The measuring component for determining the model of a femoral head prosthesis includes a first measuring device and a second measuring device. The first measuring device includes a first component fixed to the upper edge of the acetabulum and provided with a first scale and a second component fixed to the lesser trochanter of the femur. The second measuring device is provided with an opening, a sliding portion is provided in the opening, the sliding portion is provided with a connecting groove for connecting the femoral stem prosthesis, the sliding portion is also provided with a second scale and a second rack, and the second measuring device is provided with a screw rod that cooperates with the second rack gear transmission; the present invention drives the sliding portion to move the femoral stem prosthesis by the screw rod, and at the same time the first component slides out of the second component. When the first scale is equal to the normal value from the upper edge of the acetabulum to the lesser trochanter of the femur, the corresponding second scale value is the difference in radial size of the femoral head prosthesis during surgery relative to the standard femoral head prosthesis, thereby determining the model selection of the femoral head prosthesis during artificial hip replacement surgery and solving the problem of unequal length of the lower limbs after total hip replacement surgery.

[0022] 2. The present invention proposes a measuring component for determining the model of a femoral head prosthesis, wherein the first component includes a first through hole and a first measuring part, a first fixing arm is connected between the first through hole and the first measuring part, and the second component includes a second through hole and a second measuring part, a second fixing arm is connected between the second through hole and the second measuring part; the first measuring part is slidably sleeved in the second measuring part, one of the first measuring part and the second measuring part is provided with a knob part, and the other is provided with a first rack that is transmission-matched with the knob part, the first measuring part is provided with a first scale, and the combination of the first component and the second component is used to measure the distance from the upper edge of the acetabulum on the affected side of the patient to the lesser trochanter of the femur.

[0023] 3. The present invention proposes a measuring component for determining the model of a femoral head prosthesis. The first measuring part is provided with a first rack, and the second measuring part is provided with a knob part. The knob part includes a knob body and a gear. The knob body is passed through the second measuring part, and the gear is arranged inside the second measuring part and cooperates with the first measuring part in transmission. By rotating the knob body by hand, the first measuring part can be telescopically moved inside the second measuring part.

[0024] 4. The present invention proposes a measuring component for determining the model of a femoral head prosthesis. The minimum negative scale is flush with the end face of the shaft, and the measuring range of the second scale is -10 to +10 mm. The second measuring device is also provided with a notch for facilitating the turning of the screw. By turning the screw, the sliding part can slide inward 10 mm or outward 10 mm, and the second scale displays the sliding distance in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 is a schematic diagram of a first measuring device;

[0027] Figure 2 is an exploded view of the first measuring device;

[0028] Figure 3 is a schematic diagram of a second measuring device;

[0029] Figure 4 This is a second schematic diagram of the second measuring device;

[0030] Figure 5 is an exploded view of the second measuring device;

[0031] Figure 6 is a front view of a second measuring device;

[0032] Figure 7 is a schematic diagram of the sliding part;

[0033] Figure 8 It is a front view of the sliding part;

[0034] In the figure, 10, first component; 101, first through hole; 102, first measuring part; 103, first fixed arm; 104, first rack; 20, second component; 201, second through hole; 202, second measuring part; 203, second fixed arm; 30, knob part; 40, opening; 50, sliding part; 501, connecting groove; 502, second scale; 503, second rack; 504, shaft; 505, neck; 60, screw; 70, slide groove; 80, notch. DETAILED DESCRIPTION

[0035] The following combination Figure 1-8 The present invention will be described in detail.

[0036] A measuring assembly for determining the model of a femoral head prosthesis, comprising:

[0037] The first measuring device includes a first component 10 fixed to the upper edge of the acetabulum and a second component 20 fixed to the lesser trochanter of the femur. The first component 10 is slidably fitted in the second component 20. One of the first component 10 and the second component 20 is provided with a knob portion 30, and the other is provided with a first rack 104 that is transmission-engaged with the knob portion 30. The end of the first component 10 that is slidably fitted in the second component 20 is also provided with a first scale, which is used to display the distance from the upper edge of the acetabulum to the lesser trochanter of the femur.

[0038] The second measuring device is provided with an opening 40, a sliding portion 50 is provided in the opening 40 and slides along the axis of the opening 40, the sliding portion 50 is provided with a connecting groove 501 for connecting the femoral stem prosthesis, the sliding portion 50 is further provided with a second scale 502 and a second rack 503, the second scale 502 includes a plurality of negative scales, a zero scale and a plurality of positive scales, the zero scale is flush with the end surface of the notch of the connecting groove 501, and the maximum positive scale is flush with the bottom end surface of the connecting groove 501. The second measuring device is further provided with a screw 60 that is in transmission cooperation with the second rack 503;

[0039] The first component 10 and the second component 20 are fixed to the upper edge of the acetabulum and the lesser trochanter of the femur, respectively. The second measuring device is placed between the upper edge of the acetabulum and the lesser trochanter of the femur and is connected to the femoral stem prosthesis. The sliding portion 50 is driven by the screw 60 to move the femoral stem prosthesis. At the same time, the first component 10 slides out of the second component 20. When the first scale is equal to the normal value from the upper edge of the acetabulum to the lesser trochanter of the femur, the corresponding second scale 502 value is the difference in radial size of the femoral head prosthesis to be used during the operation relative to the standard femoral head prosthesis. Specifically, the first component 10 and the second component 20 are fixed to the upper edge of the acetabulum and the lesser trochanter of the femur, respectively, by locking screws with a diameter of 3.5 mm.

[0040] In this embodiment, the first component 10 includes a first through-hole 101 and a first measuring portion 102, with a first fixed arm 103 connected between the first through-hole 101 and the first measuring portion 102. The second component 20 includes a second through-hole 201 and a second measuring portion 202, with a second fixed arm 203 connected between the second through-hole 201 and the second measuring portion 202. The first measuring portion 102 is slidably mounted within the second measuring portion 202. One of the first measuring portion 102 and the second measuring portion 202 is provided with a knob portion 30, and the other is provided with a first rack 104 that engages with the knob portion 30. The first measuring portion 102 is provided with a first scale. Specifically, the first through-hole 101 and the second through-hole 201 are configured to be threadedly connected to a locking screw with a diameter of 3.5 mm. The first measuring portion 102 is rotatably connected to the first fixed arm 103, and the second measuring portion 202 is rotatably connected to the second fixed arm 203.

[0041] In this embodiment, the first measuring portion 102 is provided with a first rack 104 , and the second measuring portion 202 is provided with a knob portion 30 .

[0042] In this embodiment, the knob portion 30 includes a knob body and a gear. The knob body is disposed through the second measuring portion 202, and the gear is disposed within the second measuring portion 202 and engages with the first measuring portion 102. Specifically, when the knob body is rotated clockwise, the gear within the second measuring portion 202 also rotates clockwise, causing the first measuring portion 102, which includes the first rack 104 engaged with the gear, to extend outward, thereby increasing the distance between the first measuring portion 102 and the second measuring portion 202. When the knob body is rotated counterclockwise, the gear within the second measuring portion 202 also rotates counterclockwise, causing the first measuring portion 102, which includes the first rack 104 engaged with the gear, to retract inward, thereby decreasing the distance between the first measuring portion 102 and the second measuring portion 202.

[0043] In this embodiment, the first scale is the first rack 104. Specifically, when the first rack 104 is provided on the first measuring portion 102 and the knob portion 30 is provided on the second measuring portion 202, the first rack 104 can also function as the first scale, and thus no additional first scale is provided. When the first rack 104 is provided on the second measuring portion 202 and the knob portion 30 is provided on the first measuring portion 102, the first scale is additionally provided on the first measuring portion 102 in the form of a rack or a scale.

[0044] In this embodiment, the first rack 104 includes a plurality of meshing teeth, each with a width of 1-4 mm. Specifically, each meshing tooth is 2 mm wide, and the first rack 104 has a total of 23 meshing teeth. A 4 mm wide transition plane is also provided between the first fixed arm 103 and the first rack 104. The total length of the second measuring portion 202, which is positioned outside the first measuring portion 102, remains constant at 50 mm. Calculating the first scale requires the sum of the width of the transition plane and the width of the exposed meshing teeth, and finally adding this to the total length of the second measuring portion 202, which is 50 mm. For example, when the portion of the first measuring portion 102 exposed from the second measuring portion 202 has one occlusal tooth, the first scale indicates that the distance from the superior edge of the acetabulum to the lesser trochanter of the femur is 56 mm; when the portion of the first measuring portion 102 exposed from the second measuring portion 202 has two occlusal teeth, the first scale indicates that the distance from the superior edge of the acetabulum to the lesser trochanter of the femur is 58 mm; when the portion of the first measuring portion 102 exposed from the second measuring portion 202 has 23 occlusal teeth, the first scale indicates that the distance from the superior edge of the acetabulum to the lesser trochanter of the femur is 100 mm.

[0045] In this embodiment, a slide groove 70 is provided within the second measuring device, and the sliding portion 50 is slidably connected to the slide groove 70. Furthermore, the sliding portion 50 includes, from bottom to top, a shaft portion 504, a neck portion 505, and a connecting groove 501. The shaft portion 504 is provided with a second scale 502 and a second rack 503. The neck portion 505 is slidably connected to the slide groove 70. The connecting groove 501 is provided outside the slide groove 70.

[0046] In this embodiment, the smallest negative scale mark is flush with the end face of the shaft portion 504, and the measuring range of the second scale 502 is -10 to +10 mm. Specifically, there are five long scale marks, representing the -10, -5, 0, +5, and +10 scale marks from the outside to the inside, respectively, in millimeters. Several short scale marks are located between each long scale mark. The sliding portion 50 is driven by the screw 60 to slide within the visible range of the second scale 502. When the sliding stops, the second scale 502 displays the value corresponding to the scale mark with which the opening 40 is flush when viewed from the front. For example, if the opening 40 of the second measuring device is flush with the scale mark +1, the second scale 502 displays a value of +1.

[0047] In this embodiment, the second measuring device is provided with a notch 80 for facilitating the movement of the screw rod 60. Specifically, the screw rod 60 is moved upward to slide the sliding portion 50 inward, and the screw rod 60 is moved downward to slide the sliding portion 50 outward.

[0048] The measurement assembly for determining the model of a femoral head prosthesis proposed in the present invention is used as follows:

[0049] First, determine the normal distance, E, from the superior rim of the acetabulum to the lesser trochanter on the patient's healthy side. This distance is the distance the patient should reach after total hip replacement surgery. This normal value is calculated by taking a radiograph and then measuring it on the radiograph.

[0050] The total hip replacement procedure begins. During the procedure, osteotomy is performed, the femoral head is removed, the acetabulum is opened, and the remnants of the acetabular labrum are removed from the acetabular rim. Acetabular retractors, ranging from small to large, are then used to induce bleeding in the cancellous bone surrounding the acetabular roof and walls. A trial liner is then placed to determine the acetabular cup size. The femoral neck osteotomy is then ground with 12-15° of anteversion, and the medullary cavity is gradually expanded until it is tamped firmly into place. The femoral stem prosthesis is then inserted, and a second measuring device is placed in place of the actual femoral head prosthesis for trial molding. Simultaneously, the first component 10 of the first measuring device is screwed to the superior rim of the acetabulum, and the second component 20 is screwed to the lesser trochanter.

[0051] The screw rod 60 of the second measuring device is first moved upward or downward, causing the sliding portion 50 in the second measuring device to slide inward or outward, stopping after sliding to a certain distance. Adjusting the sliding portion 50 changes the distance between the superior edge of the patient's acetabulum and the lesser trochanter of the femur. At this point, the distance between the first through hole 101 and the second through hole 201 changes from being equal to the distance between the first measuring portion 102 and the second measuring portion 202 to being greater than or less than the distance between the first measuring portion 102 and the second measuring portion 202. To measure the current distance between the first through hole 101 and the second through hole 201 using the first measuring portion 102 and the second measuring portion 202, the knob portion 30 is manually rotated to extend or retract the first measuring portion 102 within the second measuring portion 202. The first measuring portion 102 is extended or retracted until the distance between the first through hole 101 and the second through hole 201 is equal to the distance between the first measuring portion 102 and the second measuring portion 202. At this time, check whether the distance between the first measuring part 102 and the second measuring part 202, that is, the first scale, shows the normal value E. If so, then the corresponding second scale 502 value is the difference in radial size between the femoral head prosthesis to be used during the operation and the standard femoral head prosthesis. If not, continue to turn the screw 60 to adjust the distance between the first through hole 101 and the second through hole 201, and check whether the distance reaches the normal value E after adjustment.

[0052] There are 21 models of femoral head prosthesis, and each model of femoral head prosthesis is marked with corresponding label-10 to 0 to +10, and wherein label 0 represents the femoral head prosthesis of standard model.Different models of femoral head prosthesis, the depth of their connecting groove 501 is the same, but the length between the connecting groove 501 end and the femoral head prosthesis end is different, and this section length can be called the femoral head prosthesis neck length.Femoral head prosthesis neck length is different, so the total length of femoral head prosthesis is also different.When the notch end face of the connecting groove 501 of the second measuring device is flush with opening 40, the neck length of the second measuring device at this moment is identical with the neck length of the femoral head prosthesis of standard model.When just beginning to install the second measuring device, the notch end face that sliding portion 50 is transferred to connecting groove 501 is flush with opening 40 by default, but if the numerical value that the first measuring device shows at this moment is not normal value E, just illustrate that the femoral head prosthesis of standard model can not reach the surgical effect of patient's postoperative double lower limb isometric after installing, need to install the femoral head prosthesis of other models just suitable. By turning the screw 60 to adjust the sliding part 50, when the value displayed by the first measuring device is the normal value E, the current second scale 502 value is the difference in radial size between the femoral head prosthesis to be used during the operation and the standard femoral head prosthesis. For example, if the second scale 502 shows -3, it means that the sliding part 50 has slid inward by 3mm. At this time, if the second measuring device used for trial molding is removed, the standard femoral head prosthesis cannot be installed. The standard femoral head prosthesis is too long and too large for the current affected side. Only a femoral head prosthesis with a neck length 3mm smaller than that of the standard femoral head prosthesis is suitable, that is, the femoral head prosthesis with the label -3 is selected; if the second scale 502 shows +5, it means that the sliding part 50 has slid outward by 5mm. At this time, if the second measuring device used for trial molding is removed, and the standard femoral head prosthesis is installed, the femoral head prosthesis is easy to dislocate because the standard femoral head prosthesis is too short and too small for the current affected side. Therefore, a femoral head prosthesis with a neck length 5mm longer than that of the standard femoral head prosthesis is suitable, that is, the femoral head prosthesis with the label +5 is selected.

[0053] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand and implement the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A measuring assembly for determining the model of a femoral head prosthesis, characterized in that: include: A first measuring device includes a first component fixed to the upper edge of the acetabulum and a second component fixed to the lesser trochanter of the femur, the first component slidably fitted within the second component, one of the first component and the second component being provided with a knob portion, the other being provided with a first rack that is transmission-engaged with the knob portion, and one end of the first component that slidably fits within the second component being further provided with a first scale, the first scale being used to display the distance from the upper edge of the acetabulum to the lesser trochanter of the femur; A second measuring device, wherein the second measuring device is provided with an opening, a sliding portion is provided in the opening which slides along the axis of the opening, the sliding portion is provided with a connecting groove for connecting a femoral stem prosthesis, the sliding portion is further provided with a second scale and a second rack, the second scale includes a plurality of negative scales, a zero scale and a plurality of positive scales, the zero scale is flush with the end face of the connecting groove, the largest positive scale is flush with the bottom end face of the connecting groove, and the second measuring device is further provided with a screw rod which cooperates with the second rack gear; The first component and the second component are fixed to the upper edge of the acetabulum and the lesser trochanter of the femur, respectively. The second measuring device is placed between the upper edge of the acetabulum and the lesser trochanter of the femur and is connected to the femoral stem prosthesis. The sliding part is driven by the screw to move the femoral stem prosthesis, and at the same time, the first component slides out of the second component. When the first scale is equal to the normal value from the upper edge of the acetabulum to the lesser trochanter of the femur, the corresponding second scale value is the difference in radial size of the femoral head prosthesis to be used during the operation relative to the standard femoral head prosthesis.

2. A measuring assembly for determining the model of a femoral head prosthesis according to claim 1, characterized in that: The first component includes a first through hole and a first measuring part, and a first fixed arm is connected between the first through hole and the first measuring part. The second component includes a second through hole and a second measuring part, and a second fixed arm is connected between the second through hole and the second measuring part. The first measuring part is slidably sleeved in the second measuring part, and one of the first measuring part and the second measuring part is provided with the knob part, and the other is provided with the first rack that is in transmission cooperation with the knob part. The first measuring part is provided with the first scale.

3. A measuring assembly for determining the model of a femoral head prosthesis according to claim 2, characterized in that: The first measuring part is provided with the first rack, and the second measuring part is provided with the knob part.

4. A measuring assembly for determining the model of a femoral head prosthesis according to claim 3, characterized in that: The knob portion includes a knob body and a gear. The knob body is inserted into the second measuring portion. The gear is disposed inside the second measuring portion and is in transmission cooperation with the first measuring portion.

5. A measuring assembly for determining the model of a femoral head prosthesis according to claim 3, characterized in that: The first scale is the first rack.

6. A measuring assembly for determining the model of a femoral head prosthesis according to claim 5, characterized in that: The first rack includes a plurality of engaging teeth, and the width of each engaging tooth is 1-4 mm.

7. A measuring assembly for determining the model of a femoral head prosthesis according to claim 1, characterized in that: A sliding groove is provided in the second measuring device, and the sliding part is slidably connected to the sliding groove.

8. A measuring assembly for determining the model of a femoral head prosthesis according to claim 7, characterized in that: The sliding portion includes a shaft portion, a neck portion and the connecting groove from bottom to top, the shaft portion is provided with the second scale and the second rack, the neck portion is slidably connected to the sliding groove, and the connecting groove is provided outside the sliding groove.

9. A measuring assembly for determining the model of a femoral head prosthesis according to claim 8, characterized in that: The smallest negative scale is flush with the end surface of the shaft portion, and the measuring range of the second scale is -10 to +10 mm.

10. The measuring assembly for determining the model of a femoral head prosthesis according to claim 1, wherein: The second measuring device is provided with a notch for facilitating the movement of the screw.

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