Non-image hip replacement navigation system and method based on transverse ligament positioning

Abstract

The invention belongs to the technical field of medical equipment, and discloses a non-image hip replacement navigation system and method based on transverse ligament positioning, and the system comprises a navigation positioning module, a human body horizontal plane and central axis positioning module, a transverse ligament spatial position positioning module and an acetabulum reconstruction module; the navigation positioning module is used for positioning the pose of the surgical instrument in real time; the human body horizontal plane and central axis positioning module is used for calculating an abduction angle and a front inclination angle; the transverse ligament spatial position positioning module is used for planning the shape and position of the acetabular prosthesis; and the acetabulum reconstruction module is used for implanting a prosthesis according to an intraoperative plan. According to the method, the position of the prosthesis is planned by positioning the acetabular transverse ligament, accurate intraoperative guidance is provided for acetabular grinding and prosthesis placement of a doctor, and the problems that an existing navigation system highly depends on preoperative images and intraoperative registration, so that hip replacement is complex in operation, low in efficiency and the like are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical equipment, and in particular to an image-free hip replacement navigation system and method based on transverse ligament positioning. Background Art

[0002] Hip osteoarthritis is a common joint disease in humans. It is a degenerative disease caused by wear and tear of the hip cartilage, primarily manifesting as joint pain, stiffness, and limited mobility. Total hip replacement, a proven and effective treatment for hip osteoarthritis, replaces the diseased acetabulum and femoral head with an artificial joint to restore joint function and mobility. During surgery, the placement and angle of the prosthesis are critical parameters affecting postoperative outcomes, and their accuracy is directly related to the lifespan and clinical efficacy of the artificial joint.

[0003] Traditional hip replacement surgeries mostly utilize large incisions to expose as much of the joint structure as possible, allowing the surgeon to better observe the surgical area. However, large incisions result in heavy bleeding, prolonged recovery time, and uncertain safety and accuracy. Furthermore, the implant placement and angle of the prosthesis during current hip replacements rely primarily on the surgeon's clinical experience, making it difficult to accurately determine implant placement. This often leads to prosthetic dislocation, a leading cause of revision surgery.

[0004] The surgical navigation system is a comprehensive medical device that integrates key technologies such as medical image processing, intraoperative instrument positioning, and patient-image registration. It can provide real-time spatial position information of surgical instruments relative to the lesion area, and can provide precise guidance on the operating range, boundaries, and installation position and angle of the acetabulum during hip replacement surgery.

[0005] Currently, navigation systems for hip replacement surgery typically rely on preoperative imaging data for preoperative planning. During surgery, dozens of anatomical feature points are collected from the patient's acetabulum surface for registration. This aligns the intraoperative space with the preoperative planned space to ensure accurate prosthesis installation. However, this method of preoperative imaging and intraoperative registration requires the collection of a large number of feature points, significantly increasing surgical time and reducing surgical efficiency. Furthermore, the procedure is complex and cumbersome, resulting in low physician acceptance and a lack of widespread adoption. Summary of the Invention

[0006] The present invention aims to provide an image-free hip replacement navigation system and method based on transverse ligament positioning, which is used to solve the problems that the existing navigation system is highly dependent on preoperative images and intraoperative alignment, resulting in complex hip replacement operations and low efficiency.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] An image-free hip replacement navigation system based on transverse ligament positioning includes a navigation positioning module, a human body horizontal plane and central axis positioning module, a transverse ligament spatial position positioning module, and an acetabulum reconstruction module;

[0009] The navigation and positioning module uses visual coding as positioning markers for real-time positioning of surgical instrument postures, including marker installation, registration and positioning of surgical instruments;

[0010] The human body horizontal plane and central axis positioning module determines the patient's current horizontal plane according to the navigation positioning module to calculate the abduction angle and the anteversion angle;

[0011] The transverse ligament spatial position positioning module obtains the position of the transverse ligament according to the navigation positioning module to achieve the planning of the acetabular prosthesis shape and position;

[0012] The acetabular reconstruction module implants the prosthesis according to the intraoperative plan.

[0013] Furthermore, the surgical instrument is provided with a position sensing mark, which serves as a visual positioning mark and is used to provide spatial posture information of the surgical instrument; the navigation and positioning module includes a hardware module and a software module, the hardware module includes a binocular camera, a workstation and a display screen, the binocular camera is used to track the position of the visual positioning mark in real time, the workstation is used for algorithm deployment, and the display screen is used to display the navigation and positioning results; the software module includes a visual marker recognition module, a surgical instrument registration module and a surgical instrument positioning module; the visual marker recognition module obtains the three-dimensional posture of the visual positioning mark by image processing the image stream captured by the binocular camera and detecting the two-dimensional features of the visual positioning mark; the surgical instrument registration module is used to obtain the feature distribution of the visual positioning mark, and the relative position of the tip of the surgical instrument relative to the visual positioning mark; the surgical instrument positioning module obtains the three-dimensional coordinates of the feature through a binocular triangulation method based on the visual positioning mark.

[0014] Furthermore, the registration and positioning of surgical instruments include cylindrical marker registration and tip registration and positioning; wherein, the method for cylindrical marker registration is: placing the surgical instrument with the position sensing marker attached under a binocular camera, and the binocular camera captures paired images containing position sensing marker features from multiple perspectives, these images are continuous and the position sensing marker features are overlapping, and then a multi-view reconstruction method is applied to reconstruct the marker space, and finally a global beam method is applied to optimize the final reprojection error to reduce the cumulative error in the reconstruction; the method for tip registration and positioning is: rotating the tip of the surgical instrument around a fixed point, and then determining the tip position from the spherical equation obtained from the rotating frame.

[0015] Furthermore, the human body horizontal plane and central axis positioning module includes a flat plate with position sensing marks attached and a probe tool. The flat plate is provided with a level indicator, which is placed on the operating table and leveled to determine the horizontal plane of the patient. The probe tool is used to collect human body feature points to determine the central axis in order to calculate the abduction angle and anteversion angle of the surgical instrument.

[0016] Furthermore, the abduction angle α of the surgical instrument is the angle between the surgical instrument and the central axis of the human body, and the anteversion angle β is the angle between the axis of the surgical instrument and the horizontal. The calculation method of the abduction angle α and the anteversion angle β is as follows: a plane plate with a view angle marker attached is placed on a horizontal plane to determine the coordinate system of the plane plate; during the operation, the plane plate is placed on the operating table and adjusted to the level to calculate the anteversion angle of the horizontal plane, and then a probe tool is used to touch the patient's navel and pubic symphysis respectively to determine the position of the human body midline, thereby determining the coordinate system of the patient during the operation; the tip point a (X1, Y1, Z1) of the instrument and the end feature fitting point b (X2, Y2, Z2) are set to obtain the abduction angle α and the anteversion angle β as follows:

[0017]

[0018] Furthermore, the transverse ligament spatial position positioning module plans the shape and position of the acetabular prosthesis, including the grinding angle, grinding range, shape diameter and prosthesis installation position and angle of the acetabulum shaping.

[0019] Furthermore, the method for the transverse ligament spatial position positioning module to obtain the position of the transverse ligament is: using a probe tool to contact the patient's acetabular transverse ligament, aligning the bottom edge of the hemispherical head with the bottom edge of the transverse ligament, collecting data and transmitting it to the computer, and calculating the final prosthesis position based on the preoperatively planned prosthesis size.

[0020] Furthermore, the method by which the visual marker recognition module processes the image captured by the binocular camera through image processing is one or more of a FAST corner detector, a non-maximum suppression or a triangulation algorithm.

[0021] Furthermore, the binocular camera is composed of two industrial cameras of the same model, and the two industrial cameras are connected to a workstation via a network data cable to realize data transmission; the binocular camera is fixed as a whole through a connecting plate and installed on the pan-tilt bracket of the mobile trolley.

[0022] Furthermore, the probe tool includes a probe and a hemispherical head connected by an internal hexagonal structure, and a position sensing marker is attached to the end of the probe for real-time positioning of the instrument posture; the radius size of the hemispherical head is the same as that of the acetabulum, and the plane edge of the hemisphere has a triangular mark for recording the midpoint of the transverse ligament of the acetabulum.

[0023] Furthermore, the position sensing mark is a sticker made of high-temperature resistant self-adhesive sticker, and the sticker is attached to the outer surface of the surgical instrument.

[0024] Furthermore, the mark of the sticker is a pattern composed of equilateral triangles and dots filled alternately in black and white, wherein each intersection constitutes a positioning feature point, and each feature point has self-identification.

[0025] The method for hip replacement navigation using the above-mentioned image-free hip replacement navigation system based on transverse ligament positioning includes the following steps:

[0026] S1. Use a probe tool to obtain the midpoint position of the transverse acetabular ligament, and obtain the midpoint position P1 of the transverse acetabular ligament during surgery, as well as the anteversion angle α1 and abduction angle β1 at this time;

[0027] S2. Plan the final implantation position of the prosthesis based on the position of the transverse ligament. Since the prosthesis is to be placed flush with the transverse ligament of the acetabulum, the final prosthesis position also passes through the midpoint of the transverse ligament of the acetabulum, P1, which is the common tangent point. Set the radius of the hemisphere at the time of initial contact to r1, the final prosthesis radius obtained through preoperative planning to r2, and the initial ball head position obtained through the navigation and positioning module to O1. Based on the information of the common tangent point, the final prosthesis ball center position O2 is obtained as:

[0028]

[0029] S3. The acetabulum reconstruction module performs acetabulum grinding and prosthesis implantation according to the intraoperative plan: During the operation, the doctor uses a trackable bone drill for grinding and files, and observes its abduction angle and anteversion angle in real time; during the prosthesis implantation process, the doctor obtains the position information and angle information of the prosthesis according to step S2 and the intraoperative plan, and uses the implant to accurately implant the prosthesis.

[0030] The present invention provides an image-free hip replacement navigation system and method based on transverse ligament positioning, which has the following beneficial effects:

[0031] (1) Simplified navigation operation process: This method does not require the patient's preoperative imaging data, nor does it require fluoroscopic scanning during surgery, effectively eliminating the risk of radiation exposure for both doctors and patients. Secondly, this method does not require the intraoperative registration step of traditional navigation methods, avoiding the process of collecting a large number of patient anatomical features during surgery, significantly shortening the surgical time occupied by navigation and improving surgical efficiency;

[0032] (2) Visualization of surgical data: The display screen shows the instrument position, angle, and planned prosthesis position in real time, making the doctor's operation more intuitive and confident, reducing hesitation and trial and error;

[0033] (3) Convenience of using the navigation system: After the transverse ligament position is obtained, the system can automatically calculate the precise position of the prosthesis center based on the principle of common tangency, replacing the doctor's manual measurement and estimation; and the main operation steps (placing the adjustment plate, using the probe to point the key points, and using the hemispherical head to align the ligament) are relatively intuitive, which is easier to use than interpreting complex medical images or mastering complex image navigation registration processes;

[0034] (4) High acceptance among doctors and easy to promote and apply: The system-guided standardized operating procedures help doctors with different experience levels to obtain more consistent results. It is applicable to various situations, especially patients undergoing emergency surgery or with difficulty in obtaining images. It does not require specialized imaging technicians to handle preoperative CT or operate intraoperative fluoroscopy equipment, eliminating the radiation hazards to patients and medical staff during surgery, which is in line with the development trend of minimally invasive and low-radiation surgery in modern times.

[0035] (5) Significantly improve implant accuracy and safety: The stable and critical anatomical structure of the acetabulum transverse ligament is used as the core reference point (common tangent point) for the position of the prosthesis, directly linking the prosthesis with the patient's inherent anatomy, which is more reliable and personalized than relying on intraoperative estimation or fluoroscopic images; and the navigation and positioning module based on binocular vision and coding markers can track the spatial position and posture of surgical instruments (probes, filings, and injectors) in real time and with high precision (submillimeter level), ensuring that each step of the operation (ligament positioning, filing, and implantation) is under precise monitoring. The doctor can immediately see the angle deviation and make corrections during the filing and implantation process, avoiding the disadvantages of traditional methods that rely on experience and repeated fluoroscopic confirmation, greatly reducing the risk of dislocation or impact caused by poor angles, and effectively improving the accuracy, safety and efficiency of acetabulum prosthesis implantation.

[0036] In summary, the present invention provides an image-free hip replacement navigation system and method based on transverse ligament positioning, which abandons the reliance on preoperative CT or MRI images, and does not require the acquisition of multiple acetabular surface feature points for alignment during surgery, effectively simplifying the surgical process, reducing the doctor's operating burden, and shortening the operation time. By locating the transverse ligament of the acetabulum to plan the position of the prosthesis, accurate intraoperative guidance is provided for the doctor's acetabulum grinding and prosthesis placement. In addition, during the process of acetabulum grinding and prosthesis placement, a safe boundary of the surgical area is established, and the operation is performed under visual guidance to reduce the risk of misgrinding or bone wall penetration and ensure intraoperative safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a diagram showing the components of an image-free hip replacement navigation system based on transverse ligament positioning according to the present invention;

[0038] Figure 2 This is a diagram showing the composition of a navigation and positioning module of an image-free hip replacement navigation system based on transverse ligament positioning according to the present invention;

[0039] Figure 3 Schematic diagram of the hardware modules of an image-free hip replacement navigation system based on transverse ligament positioning according to the present invention;

[0040] Figure 4 Schematic diagram of a probe tool for an image-free hip replacement navigation system based on transverse ligament positioning according to the present invention;

[0041] Figure 5 This is a diagram showing the software modules of an image-free hip replacement navigation system based on transverse ligament positioning according to the present invention;

[0042] Figure 6 This is a schematic diagram of a human body horizontal plane and central axis positioning module of an image-free hip replacement navigation system based on transverse ligament positioning according to the present invention;

[0043] Figure 7 Schematic diagram of prosthesis planning during surgery in the embodiment;

[0044] Figure 8 Schematic diagram of acetabulum grinding in the embodiment.

[0045] The names of the corresponding symbols in the accompanying drawings are:

[0046] Navigation and positioning module W100, hardware module W101, binocular camera W1011, visual positioning marker W1012, probe tool W1013, workstation W1014, display screen W1015, surgical instrument W1016, software module W102, visual marker recognition module W1021, surgical instrument registration module W1022, surgical instrument positioning module W1023, human body horizontal plane and central axis positioning module W200, transverse ligament spatial position positioning module W300, acetabulum reconstruction module W400. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0048] Example 1: Figure 1 As shown, an image-free hip replacement navigation system based on transverse ligament positioning includes a navigation positioning module W100, a human body horizontal plane and central axis positioning module W200, a transverse ligament spatial position positioning module W300 and an acetabulum reconstruction module W400;

[0049] The navigation and positioning module W100 uses visual coding as a positioning mark for real-time positioning of the surgical instrument W1016, including the mark installation, registration and positioning of the surgical instrument W1016; wherein, the surgical instrument W1016 is provided with a position sensing mark, which serves as a visual positioning mark W1012 for providing spatial posture information of the surgical instrument W1016; Figure 2 As shown, the navigation and positioning module W100 includes a hardware module W101 and a software module W102. Figure 3 As shown, the hardware module W101 includes a binocular camera W1011, a probe tool W1013, a workstation W1014 and a display screen W1015. The binocular camera W1011 is composed of two industrial cameras of the same model, and the two industrial cameras are connected to the workstation via a network port data cable to realize data transmission. The binocular camera W1011 is fixed as a whole through a connecting plate and installed on the pan-tilt bracket of the mobile trolley for real-time tracking of the position of the visual positioning marker W1012; the workstation W1014 is used for algorithm deployment, and the display screen W1015 is used to display the navigation positioning results; as shown Figure 4 As shown, the probe tool W1013 is used to obtain the position of the acetabulum transverse ligament and collect bone surface feature points, including a probe and a hemispherical head connected by an internal hexagonal structure. A position sensing mark is attached to the end of the probe for real-time positioning of the instrument posture. The radius of the hemispherical head is the same as that of the acetabulum. There is a triangular mark on the plane edge of the hemisphere for recording the midpoint of the acetabulum transverse ligament; the position sensing mark is in the form of a high-temperature resistant self-adhesive sticker, and the sticker is marked with a pattern composed of equilateral triangles and dots filled with black and white alternating fillings, where each intersection constitutes a positioning feature point, and each feature point is self-identifiable; the sticker is attached to the plane or cylindrical surface of the surgical instrument W1016, and the position sensing mark includes a first mark, a second mark, a third mark and a fourth mark. The first mark is used to determine the patient's horizontal plane, that is, the horizontal plane determination module; the second mark is used for the transverse ligament positioning module; the third mark and the fourth mark are used for the bone drill and the impactor, respectively, for locating their positions and angles;

[0050] like Figure 5 As shown, the software module W102 includes a visual marker recognition module W1021, a surgical instrument registration module W1022 and a surgical instrument positioning module W1023. The visual marker recognition module W1021 processes the image stream captured by the binocular camera W1011 through images (such as FAST corner detector, non-maximum suppression or triangulation algorithm) and detects the two-dimensional features of the visual positioning marker to obtain the three-dimensional pose of the visual positioning marker. The surgical instrument registration module W1022 is used to obtain the feature distribution of the visual positioning marker and the relative position of the tip of the surgical instrument W1016 relative to the visual positioning marker. The surgical instrument positioning module W1023 obtains the three-dimensional coordinates of the feature through the binocular triangulation method according to the visual positioning marker;

[0051] The registration and positioning of surgical instrument W1016 include cylindrical marker registration and tip registration and positioning. The cylindrical marker registration method is as follows: the surgical instrument W1016 with attached position-sensing markers is placed under a binocular camera W1011. The binocular camera W1011 captures paired images containing position-sensing marker features from multiple perspectives. These images are continuous and the position-sensing marker features overlap. A multi-view reconstruction method is then applied to reconstruct the marker space. Finally, a global bundle method is applied to optimize the final reprojection error to reduce the cumulative error in the reconstruction. The tip registration and positioning method is as follows: The tip of the surgical instrument W1016 is rotated around a fixed point, and the tip position is then determined from the spherical equation derived from the rotation frame. After the surgical instrument W1016 is registered, its position and orientation can be located in real time. During tracking, a rigid matching process is also required: overlapping features between the registered model and the features in the current captured frame are calculated. The SVD algorithm is then used to estimate undetected features and the tip position. Therefore, robust tracking can be achieved even in poor visibility conditions, such as in minimally invasive surgery, where surgeons and other instruments may obscure markers.

[0052] The human body horizontal plane and central axis positioning module determines the patient's current horizontal plane based on the navigation positioning module to calculate the abduction angle and anteversion angle; Figure 6 As shown, the human body horizontal plane and central axis positioning module includes a plane plate with a position sensing mark attached and a probe tool W1013. The plane plate is provided with a level indicator, which is placed on the operating table and leveled to determine the horizontal plane of the patient. The probe tool W1013 is used to collect human body feature points to determine the central axis to calculate the abduction angle and anteversion angle of the surgical instrument; wherein, the abduction angle α of the surgical instrument W1016 is the angle between the surgical instrument W1016 and the central axis of the human body, and the anteversion angle β is the angle between the axis of the surgical instrument W1016 and the horizontal; the calculation method of the abduction angle α and the anteversion angle β is:

[0053] Place a flat plate with position sensing markers on a horizontal surface to determine the coordinate system of the flat plate. During surgery, place the flat plate on the operating table and adjust the level to calculate the anteversion angle of the horizontal plane. Then, use the probe tool W1013 to touch the patient's navel and pubic symphysis respectively to determine the body midline position, thereby determining the patient's coordinate system during surgery. Set the instrument's tip point a (X1, Y1, Z1) and the end feature fitting point b (X2, Y2, Z2) to obtain the abduction angle α and anteversion angle β as follows:

[0054]

[0055] The transverse ligament spatial positioning module W300 uses the navigation positioning module W100 to obtain the position of the transverse ligament to plan the shape and position of the acetabular prosthesis. The shape and position of the acetabular prosthesis include the reaming angle, grinding range, shape diameter, and the position and angle of the prosthesis installation during acetabular shaping. The transverse ligament spatial positioning module W300 obtains the position of the transverse ligament by using the probe tool W1013 to contact the patient's acetabular transverse ligament, aligning the bottom edge of the hemispherical head with the bottom edge of the transverse ligament, collecting data and transmitting it to the computer, and calculating the final prosthesis position based on the preoperatively planned prosthesis size.

[0056] The acetabular reconstruction module W400 implants the prosthesis according to the intraoperative plan.

[0057] Example 2: Figure 7 and Figure 8 As shown, a hip replacement navigation method using an image-free hip replacement navigation system based on transverse ligament positioning according to Example 1 includes the following steps:

[0058] S1. Use the probe tool W1013 to obtain the midpoint position of the acetabular transverse ligament, and obtain the intraoperative midpoint position P1 of the acetabular transverse ligament, as well as the anteversion angle α1 and abduction angle β1;

[0059] S2. Plan the final implantation position of the prosthesis based on the position of the transverse ligament. Since the prosthesis is to be placed flush with the transverse ligament of the acetabulum, the final prosthesis position also passes through the midpoint of the transverse ligament of the acetabulum, P1, which is the common tangent point. Set the radius of the hemisphere at the time of initial contact to r1, the final prosthesis radius obtained through preoperative planning to r2, and the initial ball head position obtained through the navigation and positioning module W100 to O1. Based on the information of the common tangent point, the final prosthesis ball center position O2 is obtained as:

[0060]

[0061] S3. The acetabulum reconstruction module W400 performs acetabulum grinding and prosthesis implantation according to the intraoperative plan: During the operation, the doctor uses a trackable bone drill for grinding and files, and observes its abduction angle and anteversion angle in real time; during the prosthesis implantation process, the doctor obtains the position and angle information of the prosthesis according to step S2 and the intraoperative plan, and uses the implant to accurately implant the prosthesis.

[0062] The above is only an embodiment of the present invention, and common knowledge such as the specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. An image-free hip replacement navigation system based on transverse ligament positioning, characterized in that: It includes navigation positioning module, human body horizontal plane and central axis positioning module, transverse ligament spatial position positioning module and acetabulum reconstruction module; The navigation and positioning module uses visual coding as positioning markers for real-time positioning of surgical instrument postures, including marker installation, registration and positioning of surgical instruments; The human body horizontal plane and central axis positioning module determines the patient's current horizontal plane according to the navigation positioning module to calculate the abduction angle and the anteversion angle; The transverse ligament spatial position positioning module obtains the position of the transverse ligament according to the navigation positioning module to achieve the planning of the acetabular prosthesis shape and position; The acetabular reconstruction module implants the prosthesis according to the intraoperative plan.

2. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 1, characterized in that: The surgical instrument is provided with a position sensing mark, which serves as a visual positioning mark and is used to provide spatial posture information of the surgical instrument; the navigation and positioning module includes a hardware module and a software module, the hardware module includes a binocular camera, a workstation and a display screen, the binocular camera is used to track the position of the visual positioning mark in real time, the workstation is used for algorithm deployment, and the display screen is used to display the navigation and positioning results; the software module includes a visual marker recognition module, a surgical instrument registration module and a surgical instrument positioning module; the visual marker recognition module obtains the three-dimensional posture of the visual positioning mark by image processing the image stream captured by the binocular camera and detecting the two-dimensional features of the visual positioning mark; the surgical instrument registration module is used to obtain the feature distribution of the visual positioning mark and the relative position of the tip of the surgical instrument relative to the visual positioning mark; the surgical instrument positioning module obtains the three-dimensional coordinates of the feature through a binocular triangulation method based on the visual positioning mark.

3. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 2, characterized in that: The registration and positioning of surgical instruments include cylindrical marker registration and tip registration and positioning; wherein, the method for cylindrical marker registration is: placing the surgical instrument with attached position sensing markers under a binocular camera, and the binocular camera captures paired images containing position sensing marker features from multiple perspectives, these images are continuous and the position sensing marker features are overlapping, and then a multi-view reconstruction method is applied to reconstruct the marker space, and finally a global beam method is applied to optimize the final reprojection error to reduce the cumulative error in the reconstruction; the method for tip registration and positioning is: rotating the tip of the surgical instrument around a fixed point, and then determining the tip position from the spherical equation derived from the rotating frame.

4. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 3, characterized in that: The human body horizontal plane and central axis positioning module includes a plane plate with position sensing marks attached and a probe tool. The plane plate is provided with a level indicator, which is placed on the operating table and leveled to determine the patient's horizontal plane. The probe tool is used to collect human body feature points to determine the central axis, so as to calculate the abduction angle and anteversion angle of the surgical instrument.

5. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 4, characterized in that: The abduction angle α of the surgical instrument is the angle between the surgical instrument and the human body's midline, and the anteversion angle β is the angle between the surgical instrument's axis and the horizontal. The abduction angle α and anteversion angle β are calculated as follows: a flat plate with a viewpoint marker attached is placed on a horizontal plane to determine the coordinate system of the flat plate; during surgery, the flat plate is placed on the operating table and adjusted to the level to calculate the anteversion angle of the horizontal plane, and then a probe tool is used to contact the patient's navel and pubic symphysis respectively to determine the position of the human body's midline, thereby determining the patient's coordinate system during surgery; the tip point a (X1, Y1, Z1) of the instrument and the end feature fitting point b (X2, Y2, Z2) are set to obtain the abduction angle α and anteversion angle β as follows:

6. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 5, characterized in that: The transverse ligament spatial position positioning module plans the shape and position of the acetabular prosthesis, including the grinding angle, grinding range, shape diameter and prosthesis installation position and angle of the acetabulum shaping.

7. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 6, characterized in that: The method for the transverse ligament spatial position positioning module to obtain the position of the transverse ligament is: using a probe tool to contact the patient's acetabular transverse ligament, aligning the bottom edge of the hemispherical head with the bottom edge of the transverse ligament, collecting data and transmitting it to the computer, and calculating the final prosthesis position based on the prosthesis size planned before surgery.

8. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 7, characterized in that: The method by which the visual marker recognition module processes the image captured by the binocular camera is one or more of a FAST corner detector, a non-maximum suppression algorithm or a triangulation algorithm.

9. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 7, characterized in that: The binocular camera is composed of two industrial cameras of the same model, and the two industrial cameras are connected to a workstation via a network port data cable to realize data transmission; the binocular camera is fixed together through a connecting plate and installed on the pan-tilt bracket of the mobile trolley.

10. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 7, characterized in that: The probe tool includes a probe and a hemispherical head connected by an internal hexagonal structure. A position sensing marker is attached to the end of the probe for real-time positioning of the instrument. The radius of the hemispherical head is the same as that of the acetabulum, and the plane edge of the hemisphere has a triangular mark for recording the midpoint of the transverse ligament of the acetabulum.

11. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 7, characterized in that: The position sensing mark is a sticker made of high-temperature resistant self-adhesive sticker, and the sticker is attached to the outer surface of the surgical instrument.

12. The image-free hip replacement navigation system based on transverse ligament positioning according to claim 11, characterized in that: The mark of the sticker is a pattern composed of equilateral triangles and dots filled alternately in black and white, wherein each intersection constitutes a positioning feature point, and each feature point is self-identifiable.

13. A method for hip replacement navigation using the image-free hip replacement navigation system based on transverse ligament positioning according to claim 7, characterized in that: The following steps are involved: S1. Use a probe tool to obtain the midpoint position of the transverse acetabular ligament, and obtain the midpoint position P1 of the transverse acetabular ligament during surgery, as well as the anteversion angle α1 and abduction angle β1 at this time; S2. Plan the final implantation position of the prosthesis based on the position of the transverse ligament. Since the prosthesis is to be placed flush with the transverse ligament of the acetabulum, the final prosthesis position also passes through the midpoint of the transverse ligament of the acetabulum, P1, which is the common tangent point. Set the radius of the hemisphere at the time of initial contact to r1, the final prosthesis radius obtained through preoperative planning to r2, and the initial ball head position obtained through the navigation and positioning module to O1. Based on the information of the common tangent point, the final prosthesis ball center position O2 is obtained as: S3. The acetabulum reconstruction module performs acetabulum grinding and prosthesis implantation according to the intraoperative plan: During the operation, the doctor uses a trackable bone drill for grinding and files, and observes its abduction angle and anteversion angle in real time; during the prosthesis implantation process, the doctor obtains the position information and angle information of the prosthesis according to step S2 and the intraoperative plan, and uses the implant to accurately implant the prosthesis.

Images