Femoral neck rake angle measuring device adaptive to femoral stem prosthesis

Abstract

The utility model discloses a femoral neck anteversion angle measuring device adapted to a femoral stem prosthesis, which comprises a tracer and a measuring rod, a cylinder capable of being inserted into a hole is fixed at the bottom end of the measuring rod, and a bump capable of being inserted into a notch is fixed on the peripheral wall of the cylinder. In the state that the protruding block is inserted into the notch, the center line, perpendicular to the cylinder, of the protruding block is parallel to the center line of the notch, the projections, on the horizontal plane, of the protruding block and the center line of the notch coincide, and the top end of the measuring rod and the tail end of the tracer are fixedly connected and used for calibrating the center line of the protruding block. The device does not need to be sleeved on the femoral neck, does not affect hip joint reduction, still accurately measures the femoral neck rake angle after reduction, can display parameters such as lower limb length at the same time, can comprehensively analyze whether an operation is successful or not and adjust the rake angle according to requirements in combination with other parameters after reduction, improves reduction installation accuracy, and is beneficial for improving joint stability. And the dislocation risk and joint abrasion are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, in particular to a femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis. Background Art

[0002] During total hip arthroplasty (THA), appropriate anteversion is a key factor in ensuring surgical success and patient recovery. It helps increase joint stability, reduce the risk of dislocation and wear, and prolong the life of the prosthesis. The traditional method for measuring anteversion involves internally rotating the hip, flexing the knee, and positioning the lower leg perpendicular to the ground. A protractor or other device is used to measure the angle between the lower leg and the femoral neck, representing the anteversion angle. However, this method suffers from poor accuracy and reproducibility. Another approach involves using a robotic surgical system to measure anteversion. A tracer placed on the femoral neck calibrates the femoral neck axis and compares the anteversion angle to anatomical landmarks identified in CT data. While this method improves accuracy, it requires placement on the femoral neck and can only be performed in the presence of hip dislocation. It cannot simultaneously display parameters such as lower limb length and eccentricity. The procedure is cumbersome, and the anteversion displayed in the reduced position can be skewed, hindering the surgeon's judgment.

[0003] Therefore, there is an urgent need for a femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis to solve the above technical problems. Utility Model Content

[0004] The present invention aims to solve the above-mentioned technical problems, namely, to solve the problems that the existing robotic surgical system needs to be put on the femoral neck when measuring the anteversion angle, can only be performed under hip dislocation, cannot simultaneously display parameters such as lower limb length and eccentricity change, the steps are cumbersome, and the anteversion angle displayed in the reset state has deviations, which affects the surgeon's judgment.

[0005] To this end, the present invention provides a femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, wherein the shoulder of the femoral stem prosthesis is provided with a hole, and the edge of the hole is provided with a notch connected to the hole, and a center line of the notch perpendicular to the axis of the hole coincides with the projection of the axis of the femoral neck on the horizontal plane. It is characterized in that the femoral neck anteversion angle measuring device includes a tracer and a measuring rod, the bottom end of the measuring rod is fixed with a cylinder that can be inserted into the hole, and the outer peripheral wall of the cylinder is fixed with a protrusion that can be inserted into the notch, when the protrusion is inserted into the notch, the center line of the protrusion perpendicular to the cylinder and the center line of the notch are parallel to each other and their projections on the horizontal plane coincide with each other so as to achieve coincidence with the projection of the femoral neck axis on the horizontal plane, and the top end of the measuring rod is fixedly connected to the tail end of the tracer for calibrating the center line of the protrusion.

[0006] In a specific embodiment of the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, the measuring rod and the tail end of the tracer are integrally formed.

[0007] In a specific embodiment of the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, the measuring rod is provided with a groove, and the tail end of the tracer is inserted into the groove and fixedly connected.

[0008] In a specific embodiment of the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, the tail end of the tracer is fixed to the groove by bonding.

[0009] In a specific embodiment of the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, the axis of the measuring rod coincides with the axis of the tail end of the tracer.

[0010] In a specific embodiment of the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, the axis of the measuring rod forms a 90° angle with the axis of the tail end of the tracer.

[0011] In a specific embodiment of the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, the notch is a U-shaped structure, and the protrusion is a rectangular parallelepiped structure.

[0012] In the above-mentioned specific embodiment of the femoral neck anteversion angle measuring device adapted for the femoral stem prosthesis, the protrusion includes two protrusion petals, and the two protrusion petals are symmetrically fixed on the cylinder. The notch includes two notch petals, and the two notch petals are symmetrically distributed around the hole. The center line of the two notch petals coincides with the projection of the axis of the femoral neck on the horizontal plane where the center line is located. When the cylinder is inserted into the hole, the protrusion petals are inserted into the corresponding notch petals.

[0013] In a specific embodiment of the femoral neck anteversion angle measuring device adapted for the above-mentioned femoral stem prosthesis, the protrusion includes four protrusion petals, which are fixed on the cylinder in a circular array, and the notch includes four notch petals, which are distributed around the hole in a circular array, wherein the center line of two notch petals coincides with the projection of the axis of the femoral neck on the horizontal plane where the center line is located, and when the cylinder is inserted into the hole, the protrusion petals are inserted into the corresponding notch petals.

[0014] In a specific embodiment of the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, when the protrusion is inserted into the notch, the gap between the side wall thereof and the side wall of the notch is less than or equal to 0.1 mm; and / or

[0015] When the cylinder is inserted into the hole, the gap between the two is less than or equal to 0.1 mm.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] By arranging a cylinder and a bump at the bottom end of the measuring rod, when the cylinder is inserted into the hole on the shoulder of the femoral stem prosthesis, the bump is inserted into the gap so that the center line of the bump perpendicular to the axis of the cylinder coincides with the projection of the center line of the gap on the horizontal plane. Since the center line of the gap coincides with the projection of the axis of the femoral neck on the horizontal plane, the center line of the bump coincides with the projection of the axis of the femoral neck on the horizontal plane. In this way, the axis of the femoral neck can be calibrated by calibrating the center line of the bump with a tracer. The navigation system of the surgical robot can determine the location of the femoral neck axis by identifying the tracer. At the location, the anteversion angle of the femoral neck is determined in combination with the anatomical landmarks of the CT data. Since the connection between the tracer and the femoral stem is the hole on the shoulder of the femoral stem prosthesis, it does not need to be put on the femoral neck, which does not affect the reduction of the hip joint. The femoral neck anteversion angle can still be accurately measured after reduction, and parameters such as lower limb length and eccentricity change can be displayed at the same time. Other parameters after reduction can be combined to comprehensively analyze whether the operation is successful and adjust the anteversion angle as required, which improves the accuracy of reduction and installation, helps to increase joint stability, reduce the risk of dislocation and joint wear, and extend the service life of the prosthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0019] Figure 1 This is a schematic diagram of the overall structure of the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis provided by the present invention;

[0020] Figure 2 yes Figure 1 A partial enlarged view of middle A;

[0021] Figure 3 yes Figure 1 A schematic diagram of the structure of another angle at which the measuring rod, cylinder and bump are connected;

[0022] Figure 4 yes Figure 3 Left view of;

[0023] Figure 5 It is the distribution map of holes and notches on the femoral stem prosthesis;

[0024] Figure 6 yes Figure 5 A top view of

[0025] Figure 7 This is a schematic diagram of the structure in which a cylinder is inserted into a hole and a bump is inserted into a notch for measurement;

[0026] Figure 8 It is a schematic diagram of the shape of the gap when viewed from above;

[0027] Figure 9 It is a bump with Figure 8 Schematic diagram of the structure of the gap fit;

[0028] Figure 10 It is a schematic diagram of another shape of the notch when viewed from above;

[0029] Figure 11 It is a bump with Figure 10 Schematic diagram of the structure of the gap fit;

[0030] Figure 12 This is a schematic diagram of the installation structure in which the axis of the measuring rod and the axis of the tail end of the tracer are at 90 degrees.

[0031] List of reference numerals:

[0032] 1. Tracer; 2. Measuring rod; 3. Cylinder; 4. Bump; 41. Bump flap; 5. Femoral stem prosthesis; 6. Femoral neck; 7. Hole; 8. Notch; 81. Notch flap; 9. Long rod. DETAILED DESCRIPTION

[0033] To make the purpose, technical solution, and advantages of the present invention more clearly apparent, the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0034] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They are not intended to indicate or imply that the systems or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the use of terms such as "first" and "second" to define components is intended solely to facilitate distinction between such components. Unless otherwise stated, these terms have no special meanings and should not be construed as indicating or implying relative importance.

[0035] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "installed," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0036] The utility model relates to the field of medical device technology, and in particular to a femoral neck anteversion angle measurement device adapted for a femoral stem prosthesis. The purpose is to address the problems of existing robotic surgical systems that require a sleeve around the femoral neck when measuring anteversion angle, can only be performed under hip dislocation, cannot simultaneously display parameters such as lower limb length and eccentricity changes, and are cumbersome. Furthermore, the anteversion angle displayed in the reset state may be biased, affecting the surgeon's judgment. To this end, the utility model provides a femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, comprising a tracer and a measuring rod, wherein a cylinder capable of being inserted into a hole is fixed to the bottom end of the measuring rod, and a protrusion capable of being inserted into a notch is fixed to the outer peripheral wall of the cylinder. When the protrusion is inserted into the notch, a center line of the protrusion perpendicular to the cylinder and a center line of the notch are parallel to each other, and their projections on the horizontal plane coincide with each other so as to coincide with the projection of the femoral neck axis on the horizontal plane. The top end of the measuring rod is fixedly connected to the tail end of the tracer for calibrating the center line of the protrusion. Since the connection between the tracer and the femoral stem is the hole on the shoulder of the femoral stem prosthesis, it does not need to be put on the femoral neck, and does not affect the reduction of the hip joint. After reduction, the femoral anteversion angle can still be accurately measured, and parameters such as lower limb length and eccentricity change can be displayed simultaneously. Other parameters after reduction can be combined to comprehensively analyze whether the operation is successful and adjust the anteversion angle as required, thereby improving the accuracy of reduction and installation, helping to increase joint stability, reduce the risk of dislocation and joint wear, and extend the service life of the prosthesis.

[0037] Hereinafter, the femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis provided by an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0038] See Figure 1-7The present invention provides a femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis. A hole 7 is provided on the shoulder of the femoral stem prosthesis 5. A notch 8 communicating with the hole is provided at the edge of the hole 7. A center line of the notch 8 perpendicular to the axis of the hole 7 coincides with the projection of the axis of the femoral neck 6 on the horizontal plane. The femoral neck 6 anteversion angle measuring device comprises a tracer 1 and a measuring rod 2. A cylinder 3 capable of being inserted into the hole 7 is fixed to the bottom end of the measuring rod 2. A protrusion 4 capable of being inserted into the notch 8 is fixed on the outer peripheral wall of the cylinder 3. The protrusion cooperates with the notch. When the protrusion 4 is inserted into the notch 8, the center line of the protrusion 4 perpendicular to the cylinder 3 and the center line of the notch 8 are parallel to each other and their projections on the horizontal plane coincide with each other so as to achieve the projection of the femoral neck axis on the horizontal plane. The top end of the measuring rod 2 is fixedly connected to the tail end of the tracer 1 for calibrating the center line of the protrusion 4. The axis of the cylinder 3 coincides with the axis of the measuring rod 2.

[0039] The tracer 1 can be an existing tracer 1, including a reflective ball holder and multiple reflective balls, wherein the multiple reflective balls are asymmetrically and non-collinearly arranged on the reflective ball holder, and the measuring rod 2 is fixedly connected to the long rod of the reflective ball holder, and the tail end of the tracer is the tail end of the long rod. The navigation system of the surgical robot can identify the reflective ball of the tracer 1 and thus identify the tracer 1. The calibration of the axis of the measuring rod 2 and the center line of the bump 4 is completed using an articulated arm three-dimensional coordinate measuring machine. The specific process is to first stick the measuring rod 2 firmly on the table, then use the three-dimensional coordinate measuring machine to align the reflective ball surface, sample the cylindrical surface of the long rod on the reflective ball holder of the tracer 1 and the surface of the bump 4, obtain the point coordinates of the surface, and then use the three-dimensional coordinate measuring machine software to perform spherical fitting, cylindrical fitting and plane fitting to obtain the axis of the measuring rod 2 and the center line features of the bump 4 that we are concerned about. A coordinate system is established based on these features, and finally the coordinates of the four reflective balls are output based on this coordinate system. By identifying the reflective ball under an optical camera, we can obtain the established coordinate system, thereby determining the position and orientation of the axis of the measuring rod 2 and the centerline of the bump 4. In this application, the centerline of the bump 4 refers to the centerline parallel to the horizontal plane. Since the calibration method for the axis of the long rod of the reflective ball holder (i.e., the axis of the measuring rod 2) and the centerline of the bump 4 is common knowledge to those skilled in the art, it will not be described in detail here.

[0040] It should be noted that a hole 7 and a notch 8 are provided on the femoral stem prosthesis 5. The hole 7 is used to install and fix the femoral neck 6. When the rotation angle of the femoral neck 6 needs to be adjusted, the rotation angle can be adjusted by acting on the hole 7 and the notch 8 with the help of external tools.

[0041] When measuring, first insert the cylinder 3 into the hole 7, and then insert the protrusion 4 into the notch 8. At this time, the center line of the protrusion 4 perpendicular to the axis of the cylinder 3 coincides with the projection of the center line of the notch 8 on the horizontal plane. Since the center line of the notch 8 coincides with the projection of the axis of the femoral neck 6 on the horizontal plane (such as Figure 6 (as shown by the dotted line in the figure), the centerline of the bump 4 coincides with the horizontal projection of the axis of the femoral neck 6. Thus, by calibrating the centerline of the bump 4 with the tracer 1, the axis of the femoral neck 6 can be calibrated. The surgical robot's navigation system can identify the tracer 1 to determine the location of the axis of the femoral neck 6 and, in conjunction with the anatomical landmarks in the CT data, determine the anteversion angle of the femoral neck 6. Because the connection between the tracer 1 and the femoral stem is through the hole 7 on the shoulder of the femoral stem prosthesis 5, it does not need to be placed on the femoral neck 6, which does not affect the reduction of the hip joint. After reduction, the anteversion angle of the femoral neck 6 can still be accurately measured, and parameters such as lower limb length and eccentricity changes can be simultaneously displayed. The success of the surgery can be comprehensively analyzed in combination with other parameters after reduction.

[0042] In one embodiment, the notch 8 is in a U-shaped structure. In order to adapt to the shape of the notch 8, the protrusion 4 is designed to be a rectangular parallelepiped structure. It should be noted that although the notch is in a U-shaped shape and the protrusion is in a rectangular parallelepiped as described above, this is only an example and other structures are also possible. For example, see Figure 9 and Figure 8 The convex block includes two convex block petals, which are symmetrically fixed on the cylinder. The notch includes two notch petals, which are symmetrically distributed around the hole. The center line of the two notch petals coincides with the projection of the axis of the femoral neck on the horizontal plane where the center line is located. When the cylinder is inserted into the hole, the convex petals are inserted into the corresponding notch petals. Figure 8 The dotted line in the figure represents the center line of the gap. Figure 9 The dotted line in FIG represents a center line of the protrusion and is parallel to the center line of the notch when inserted into the notch. Figure 10 and Figure 11 The protrusion includes four protrusion petals fixed to the cylinder in a circumferential array, and the notch includes four notch petals distributed in a circumferential array around the hole. The centerline of two notch petals coincides with the projection of the axis of the femoral neck on the horizontal plane of the centerline. When the cylinder is inserted into the hole, the protrusion petals are inserted into the corresponding notch petals. All of this is within the scope of protection of this application. Figure 10 The dotted line in the figure represents the center line of the gap. Figure 11 The dotted line in FIG. 1 represents a center line of the bump and is parallel to the center line of the notch when the bump is inserted into the notch.

[0043] In one embodiment, the measuring rod 2 is integrally formed with the tail end of the tracer 1. Specifically, the measuring rod 2 and the bracket of the tracer 1 are an integrated structure.

[0044] In one embodiment, a groove is provided on the measuring rod 2, and the tail end of the tracer 1 is inserted into the groove and fixedly connected. The tail end of the tracer 1 refers to the tail end of the long rod on the reflective ball bracket. This application does not specifically limit the fixing method between the tail end of the tracer and the groove. For example, the tail end of the tracer 1 and the groove are fixed by bonding. The measuring rod 2 and the tracer 1 are designed to be detachable, which facilitates the replacement of the measuring rod 2 and is more convenient to use.

[0045] In one embodiment, the axis of the measuring rod coincides with the axis of the tail end of the tracer (the axis of the long rod). Figure 4 shown.

[0046] It should be noted that although the axis of the measuring rod described above coincides with the axis of the tail end of the tracer, this is only an example and not a limitation. It can also be in other forms. For example, the axis of the measuring rod is 90° to the axis of the tail end of the tracer, such as Figure 12 As shown, the groove is set on the side wall of the measuring rod. Therefore, the installation angle between the tracer and the measuring rod needs to be flexibly set.

[0047] In one embodiment, when the projection 4 is inserted into the notch 8, the clearance between the sidewalls of the projection 4 and the sidewalls of the notch 8 is less than or equal to 0.1 mm. This relatively small clearance between the projection 4 and the notch 8 ensures that the centerline of the projection 4 is parallel to the centerline of the notch 8 after the projection 4 is inserted into the notch 8, i.e., on the same plane. This ensures the accuracy of determining the axis of the femoral neck 6, thereby improving the accuracy of anteversion angle measurement.

[0048] In one embodiment, the gap between the cylinder 3 and the hole 7 is less than or equal to 0.1 mm, which ensures that the cylinder 3 is restrained after being inserted into the hole 7, so that the measuring rod 2 and the tracer 1 do not swing, which is beneficial to the measurement accuracy.

[0049] In the present application, the cylinder 3 and the measuring rod 2 are an integrated structure, and the connection between the cylinder 3 and the measuring rod 2 is firm, preventing the relative position between the bump and the reflective ball in the tracer from changing.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the protection scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis, wherein a hole is provided at the shoulder of the femoral stem prosthesis, a notch is provided at the edge of the hole and is connected to the hole, a center line of the notch perpendicular to the axis of the hole coincides with the projection of the axis of the femoral neck on the horizontal plane where the center line is located, characterized in that: The femoral neck anteversion angle measuring device includes a tracer and a measuring rod, a cylinder that can be inserted into the hole is fixed to the bottom end of the measuring rod, a protrusion that can be inserted into the notch is fixed on the outer wall of the cylinder, when the protrusion is inserted into the notch, a center line on the protrusion that is perpendicular to the cylinder is parallel to the center line of the notch and their projections on the horizontal plane coincide with each other so as to achieve coincidence with the projection of the femoral neck axis on the horizontal plane, and the top end of the measuring rod is fixedly connected to the tail end of the tracer for calibrating the center line of the protrusion.

2. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 1, characterized in that: The measuring rod and the tail end of the tracer are integrally formed.

3. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 1, characterized in that: The measuring rod is provided with a groove, and the tail end of the tracer is inserted into the groove and fixedly connected.

4. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 3, characterized in that: The tail end of the tracer is fixed to the groove by bonding.

5. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 1, characterized in that: The axis of the measuring rod coincides with the axis of the tail end of the tracer.

6. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 1, characterized in that: The axis of the measuring rod is at 90° to the axis of the tail end on the tracer.

7. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 1, characterized in that: The notch is in a U-shaped structure, and the protrusion is in a rectangular parallelepiped structure.

8. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 1, characterized in that: The protrusion includes two protrusion petals, which are symmetrically fixed on the cylinder. The notch includes two notch petals, which are symmetrically distributed around the hole. The overlapping center line of the two notch petals coincides with the projection of the axis of the femoral neck on the horizontal plane where the center line is located. When the cylinder is inserted into the hole, the protrusion petals are inserted into the corresponding notch petals.

9. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 1, characterized in that: The protrusion includes four protrusion petals, which are fixed on the cylinder in a circular array. The notch includes four notch petals, which are distributed around the hole in a circular array, wherein the center line of two notch petals coincides with the projection of the axis of the femoral neck on the horizontal plane where the center line is located, and when the cylinder is inserted into the hole, the protrusion petals are inserted into the corresponding notch petals.

10. The femoral neck anteversion angle measuring device adapted for a femoral stem prosthesis according to claim 1, characterized in that: When the protrusion is inserted into the notch, the gap between the side wall of the protrusion and the side wall of the notch is less than or equal to 0.1 mm; and / or When the cylinder is inserted into the hole, the gap between the two is less than or equal to 0.1 mm.

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