An intraoperative tension adjustable graft fixation device and method of fixation

Abstract

The application discloses an intraoperative tension-adjustable graft fixing device and fixing method. The device comprises a bone fixing base and a tension-adjusting assembly which is movably connected to the bone fixing base and comprises a lever arm, a sliding torque converter, a graft connecting piece and a pre-tightness adjusting knob. The two ends of the lever arm are respectively a connecting end and an adjusting end. The sliding torque converter is arranged between the adjusting end and the bone fixing base. The graft connecting piece is arranged at the connecting end. The pre-tightness adjusting knob is connected to the end of the rotating shaft and extends to the outside. The application maps the joint activity angle to the change of the force arm through the cooperation of the lever arm and the sliding torque converter, so that the equivalent tension at the graft connecting piece and the rotating angle of the lever arm are in a non-linear inverse correlation relationship. Meanwhile, the pre-tightness adjusting knob can set the initial frictional damping in the operation. The application realizes the dynamic self-adaptive adjustment of the graft tension, solves the problem of re-tearing caused by the tension imbalance after the rotator cuff repair, and is safe, reliable and easy to operate.

Description

Technical Field

[0001] This invention specifically relates to an intraoperative tension-adjustable graft fixation device and fixation method. Background Technology

[0002] Rotator cuff tears are common musculoskeletal injuries, and arthroscopic rotator cuff repair is currently the mainstream surgical procedure. One of the core steps of this surgery is to reposition and securely fix the torn supraspinatus tendon and other grafts to the bone surface of the greater tuberosity of the humerus, creating a stable biomechanical environment for healing. However, clinical statistics show that the re-tear rate after rotator cuff repair, especially in the early postoperative period (within 6 months), remains high, posing a significant challenge for orthopedic surgeons and patients.

[0003] In-depth research shows that one of the key risk factors leading to postoperative re-tears lies in the inherent contradiction between the "static" characteristics of traditional fixation methods and the "dynamic" physiological activities of the shoulder joint. The shoulder joint has the largest range of motion in the human body. During daily activities, the physiological tension on the supraspinatus tendon and joint capsule is not constant, but rather exhibits complex dynamic changes with shoulder abduction, adduction, and rotation. For example, in a neutral shoulder position, the tendon is relatively relaxed; when abducted to a certain angle (such as around 60°), the tendon tension reaches its peak; with continued abduction, the tension may actually decrease.

[0004] However, existing graft fixation devices, whether single-row anchors, double-row anchors, or suture bridges, are essentially "rigid fixation" or "static fixation." They firmly fix the tendon to a single point on the bone surface, failing to adapt to the complex dynamic tension changes described above. If the fixation is too tight, the tendon will experience abnormally high stress during joint movement, causing micro-tears at the suture interface or even tendon laceration; if the fixation is too loose, it cannot provide sufficient initial stability for tendon healing, leading to repair failure. Although some studies have attempted to use elastic or absorbable materials to buffer stress, these solutions only provide linear, elongation-proportional buffering force, failing to achieve non-linear adjustment related to joint angles. In other words, they cannot provide maximum compliance at the angles most in need of protection while providing sufficient support at safe angles. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the technical problem to be solved by this invention is to provide an intraoperative tension-adjustable graft fixation device and fixation method that can dynamically balance tendon tension in real time according to shoulder joint movement, thereby effectively reducing the risk of postoperative re-tear.

[0006] To achieve the above objectives, the present invention provides a technique as follows: an intraoperative tension-adjustable graft fixation device, comprising: Bone fixation base, which can be fixedly connected to the bone surface; Tension adjustment assembly, movably connected to the bone fixation base, the tension adjustment assembly comprising: A lever arm, the middle part of which is pivotally connected to the bone fixation base via a pivot, and the two ends of the lever arm are a connecting end and an adjusting end, respectively; A sliding torque converter is disposed between the adjusting end of the lever arm and the bone fixation base, and is used to change the lever arm length of the lever arm; A graft connector is provided at the connecting end of the lever arm for connecting to the graft; A preload adjustment knob is connected to the end of the rotating shaft and extends to the outside of the bone fixation base, used to adjust the frictional damping of the rotating shaft; The lever arm tends to rotate around the pivot under the tension transmitted by the graft, and the sliding torque converter can change the support position according to the rotation angle of the lever arm, so that the equivalent tension at the graft connector has a non-linear inverse correlation with the rotation angle of the lever arm.

[0007] Furthermore, the bone fixation base includes: Base body; A fixation part, disposed on the bottom surface of the base body, is used for implantation into the bone; the fixation part is a screw rod with self-tapping threads or a press-fit anchor. A receiving cavity is provided at the top of the base body for accommodating the adjusting end and the sliding torque converter.

[0008] Furthermore, the sliding torque converter includes: A curved slide rail is fixed to the bone fixation base, and the center of the trajectory of the curved slide rail is located on the axis of the rotating shaft; and The slider is slidably disposed within the curved slide rail, and the connecting end is an elastic telescopic rod that is hinged to the slider.

[0009] Furthermore, the trajectory radius of the curved slide rail changes continuously along the circumference to form a cam profile surface.

[0010] Furthermore, the graft connector includes: A guide wheel is rotatably mounted on the connecting end; A flexible traction wire, the first end of which is used to connect the graft, and the second end of which passes around the guide wheel and is fixed to the bone fixation base.

[0011] Furthermore, the graft connector also includes a hook disposed at the first end of the flexible traction line.

[0012] Furthermore, the outer periphery of the guide wheel is provided with a plurality of annular grooves arranged along the axial direction for accommodating the plurality of flexible traction wires respectively.

[0013] Furthermore, a traction fixation post is provided on the bone fixation base, and the second end of the flexible traction line is fixed to the traction fixation post.

[0014] Furthermore, the preload adjustment knob includes a friction plate and an adjustment screw. The friction plate is mounted on the rotating shaft. The middle part of the adjustment screw is threadedly connected to the bone fixation base. The end of the adjustment screw is rotatably connected to the friction plate. Rotating the adjustment screw increases the clamping force that presses the friction plate against the rotating shaft.

[0015] A method for tension-adjustable graft fixation using the aforementioned intraoperative tension-adjustable graft fixation device includes the following steps: Fix the bone fixation base to the bone surface; Connect the graft connector to the graft, rotate the preload adjustment knob, and adjust the screw to drive the friction plate to change the clamping force on the rotating shaft, thus setting the initial tension; During postoperative joint movement, the graft drives the lever arm to rotate around the axis via the graft connector; The lever arm adjustment end drives the slider hinged to it to slide along the curved slide rail. The variable radius cam profile of the curved slide rail changes the support position of the slider on the adjustment end, thereby dynamically adjusting the lever arm length. By utilizing the lever principle, the equivalent tension at the graft connector is non-linearly inversely correlated with the rotation angle of the lever arm, thereby dynamically maintaining the graft tension within a preset range.

[0016] The beneficial effects of this invention are: The above-mentioned intraoperative tension-adjustable graft fixation device and fixation method have at least the following advantages: First, this invention uses a purely mechanical tension adjustment assembly consisting of a lever arm and a sliding torque converter to physically map the joint movement angle to changes in the lever arm of the lever system. When joint movement causes a change in the tension on the graft, the lever arm rotates accordingly, and the sliding torque converter changes its support position on the adjusting end of the lever arm based on the rotation angle, thereby dynamically adjusting the lever arm length. According to the lever principle, this dynamic change in the lever arm creates a "non-linear inverse correlation" between the equivalent tension at the graft connector and the rotation angle of the lever arm (i.e., the joint movement angle). This means that when the joint moves to a specific angle that is most likely to cause excessive tendon traction and injury, the actual tension acting on the graft will automatically decrease due to the increase in the lever arm, achieving a mechanical protection mechanism similar to "negative feedback." This dynamic adaptive characteristic completely changes the shortcomings of traditional static fixation methods that cannot adapt to dynamic joint movement, fundamentally solving the problem of micro-tears and re-tears caused by tension imbalance.

[0017] Secondly, this invention features a preload adjustment knob extending to the outside of the bone fixation base at the end of the rotating shaft. During surgery, the surgeon can precisely adjust the frictional damping of the rotating shaft by rotating this knob, based on the patient's specific condition as determined during the operation, such as tendon mass, tear size, and bone density. This allows the surgeon to tailor an optimal initial working state and tension baseline for each patient, embodying the concept of precision medicine and further improving the success rate of surgery. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of an intraoperative tension-adjustable graft fixation device according to an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the intraoperative tension-adjustable graft fixation device from another angle is shown; Figure 3 for Figure 1 A cross-sectional view of the lever arm in the intraoperative tension-adjustable graft fixation device shown; Figure 4 for Figure 1 The diagram shows a slide rail in an intraoperative tension-adjustable graft fixation device. Figure 5 for Figure 1 A schematic diagram at point A in the middle; Figure 6 for Figure 1 A schematic diagram at point B in the middle; Figure 7 for Figure 1 A schematic diagram of the pretension adjustment knob in the intraoperative tension-adjustable graft fixation device is shown. Figure 8 This is a schematic diagram of an intraoperative tension-adjustable graft fixation method according to an embodiment of the present invention; Figure label: 100. Bone fixation base; 110. Base body; 120. Fixation part; 130. Receiving cavity; 200. Tension adjustment assembly; 210. Lever arm; 211. Connecting end; 212. Adjusting end; 213. Rotating shaft; 220. Sliding torque converter; 221. Curved slide rail; 222. Slider; 230. Graft connector; 231. Guide wheel; 232. Flexible traction line; 233. Hook; 234. Traction fixation post; 240. Preload adjustment knob; 241. Friction pad; 242. Adjusting screw. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention; therefore, the invention is not limited to the specific embodiments disclosed below.

[0021] Please see Figures 1 to 7 This embodiment provides an intraoperative tension-adjustable graft fixation device, which is mainly used in rotator cuff repair surgery to fix grafts such as the supraspinatus tendon to the surface of the humerus and can dynamically adjust the tension on the tendon with the movement of the shoulder joint.

[0022] Please see Figure 1 and Figure 2 The intraoperative adjustable tension graft fixation device of this embodiment mainly includes the following parts: The bone fixation base 100 serves as the mounting foundation for the entire device. It is made of medical-grade titanium alloy or PEEK material, and its overall structure is designed to firmly bond with the bone surface. During surgery, the bone fixation base 100 is fixed to the pre-prepared bone hole through its bottom structure, ensuring that it will not loosen or shift during postoperative recovery.

[0023] The tension adjustment component 200 is movably connected to the bone fixation base 100, and the component specifically includes: The lever arm 210 is a long, rigid component, the central portion of which is rotatably mounted on the bone fixation base 100 via a transversely arranged pivot 213. The axis of the pivot 213 is substantially parallel to the bone surface. The lever arm 210, with the pivot 213 as its fulcrum, forms a seesaw-like structure, with a connecting end 211 and an adjusting end 212 at its two ends. The connecting end 211 is located outside the bone fixation base 100 and is used to connect the graft to be fixed; the adjusting end 212 is located inside the bone fixation base 100 and is used to cooperate with the sliding torque converter 220 described below.

[0024] A sliding torque converter 220 is positioned between the adjusting end 212 of the lever arm 210 and the inner wall of the bone fixation base 100. This is a crucial variable lever arm mechanism, whose function is to dynamically change the support position of the lever arm 210's adjusting end 212 according to the rotation angle of the lever arm 210. The change in support position directly causes a change in the distance (i.e., lever arm length) from the adjusting end 212 to the rotating shaft 213, thereby altering the mechanical amplification factor of the entire lever system.

[0025] The graft connector 230 is disposed at the connecting end 211 of the lever arm 210. It is an interface component for reliably connecting the graft (such as a sutured tendon end) to the lever arm 210 and transmitting the tension on the graft to the lever arm 210.

[0026] The preload adjustment knob 240 has its inner end connected to the rotating shaft 213. During surgery, the surgeon can adjust the frictional resistance of the rotating shaft 213 by rotating this knob. This design allows the surgeon to set a suitable initial working state for the device according to the patient's specific condition (such as tissue quality, tear size, etc.), reflecting the characteristic of "intraoperative adjustability".

[0027] In use, when the graft is subjected to tension, this tension acts on the connecting end 211 of the lever arm 210 through the graft connector 230. Since the lever arm 210 can rotate around the pivot 213, this tension generates a torque that causes the lever arm 210 to rotate around the pivot 213. The rotation of the lever arm 210 causes its adjusting end 212 to move, thereby changing the lever arm length of the adjusting end 212. The sliding torque converter 220 senses this positional change and accordingly changes its support point on the adjusting end 212. This change in support point essentially changes the fulcrum position or force-bearing point position of the lever system, thus creating a "non-linear inverse correlation" between the equivalent tension of the connecting end 211 and the rotation angle of the lever arm 210 (i.e., the joint's range of motion). Simply put, when the joint moves to certain angles that easily lead to excessive tendon traction, the actual tension acting on the graft is reduced through the adjustment of the sliding torque converter 220, thereby achieving dynamic protection.

[0028] Based on Example 1, this example further refines the structure of the bone fixation base 100.

[0029] Please see Figure 1 and Figure 2 The bone fixation base 100 specifically includes three parts: the base body 110, the fixation part 120, and the receiving cavity 130.

[0030] The base body 110 is the main body of the entire device, and is usually designed as a flat block or column to attach to the bone surface.

[0031] The fixation part 120 is located on the bottom surface of the base body 110. The fixation part 120 can take two common forms: one is a screw rod with self-tapping threads, which the doctor can directly screw into a pre-drilled bone hole, achieving fixation through the engagement of the threads with the bone. This method provides reliable fixation and is suitable for patients with good bone health. The other is a press-fit anchor, whose surface usually has barbs, grooves, or a coating. It is implanted into a bone hole slightly smaller than its diameter by tapping, relying on the interference fit and the anti-dislodgement effect of the barbs to achieve fixation. This method allows for fast implantation and causes less damage to the bone. The two forms can be selected according to clinical needs, expanding the applicability of the device.

[0032] The receiving cavity 130 is located at the top of the base body 110 and is a hollow cavity. The internal space of this cavity is precision machined to accommodate the adjusting end 212 of the lever arm 210 and the entire sliding torque converter 220. The design of the receiving cavity 130 not only provides protection for the internal moving parts, but also serves as a guide and limiter, ensuring that the lever arm 210 and the sliding torque converter 220 can move precisely along a predetermined trajectory.

[0033] In this embodiment, the sliding torque converter 220 includes a curved slide rail 221 and a slider 222.

[0034] The curved slide rail 221 is a curved track fixed to the inner wall of the cavity 130 of the bone fixation base 100. The center of the track's trajectory lies exactly on the axis of the pivot 213 of the lever arm 210.

[0035] Please see Figure 3The slider 222 is a slidable block component whose bottom shape is adapted to the curved slide rail 221, and it is slidably embedded in the rail. A key improvement in this embodiment is that the connecting end 211 of the lever arm 210 is designed as an elastic telescopic rod, and the end of this elastic telescopic rod is connected to the slider 222 via a hinge. An "elastic telescopic rod" refers to a rod that has a certain telescopic capacity in the axial direction (e.g., containing a micro-spring or made of elastic material), and this telescopic capacity is elastic and recoverable. The hinged connection allows not only the transmission of thrust between the connecting end 211 and the slider 222, but also adaptation to small changes in their angle and distance, avoiding the jamming or sticking that might occur with a rigid connection.

[0036] When lever arm 210 rotates around pivot 213, the movement trajectory of its adjusting end 212 (i.e., the elastic telescopic rod) is an arc around pivot 213. Since adjusting end 212 is connected to slider 222 via a hinge, the movement of adjusting end 212 causes slider 222 to slide along curved slide rail 221, which also centers on pivot 213. The elastic telescopic rod's design serves as a buffer and adaptive fine-tuning mechanism: when slider 222 encounters resistance or changes in slide rail curvature during its movement within the slide rail, the elastic telescopic rod can absorb positional errors through extension and retraction, ensuring that slider 222 always maintains good contact with the slide rail and moves smoothly.

[0037] In this embodiment, the trajectory radius of the curved slide rail 221 changes continuously along its circumference (i.e., the sliding direction of the slider 222), thereby forming a cam profile surface. That is to say, this arc track is not a standard circular arc (with a constant radius), but a curve with variable curvature.

[0038] Because the slide rail has a variable radius, the radial distance (i.e., the radius of curvature of the slide rail at that point) between the slider 222 and the axis of the rotating shaft 213 is different when the slider 222 is in different positions. The slider 222 is connected to the adjusting end 212 of the lever arm 210 via a hinge; therefore, the position of the slider 222 directly determines the spatial position of the adjusting end 212 relative to the rotating shaft 213. The perpendicular distance from this position to the axis of the rotating shaft 213 is the actual lever arm length of the adjusting end 212 of the lever arm 210. For example: The slide rail trajectory can be designed as follows: initial position (corresponding to joint 0°) radius 8mm (R1); rotation 10° (corresponding to joint 30°) radius gradually decreases to 10mm (R2); rotation 20° (corresponding to joint 60°) radius increases to a maximum of 15mm (R3); rotation 30° (corresponding to joint 90°) radius decreases back to 12mm (R4). This "increase-decrease" contour can minimize tendon tension around 60°.

[0039] Based on the lever principle, the formula can be derived as follows: F1×L1=F2×L2.

[0040] Where F1 is the tendon end tension, L1 is the distance from the pivot to the end of the connection (fixed value), F2 is the supporting force of the slider on the end of the lever arm adjustment (determined by the elastic force at the end of the adjustment and the normal reaction force of the slide rail), and L2 is the length of the adjustment end (variable value).

[0041] See Figure 4 By carefully designing this cam profile surface (i.e., the law of "continuous change of trajectory radius along the circumference"), arbitrary nonlinear changes in the lever arm length can be achieved with the rotation angle of lever arm 210 (i.e., joint movement angle). Specifically, as shown in the figure, it can be designed such that: in the neutral joint position, slider 222 is located in the section with a smaller slide rail radius (R1), and the lever arm of adjusting end 212 is shorter; as the joint abduction angle increases, slider 222 is pushed into the section with a gradually increasing slide rail radius, and the lever arm of adjusting end 212 also increases accordingly; when the joint is abducted to 60°, where tendon injury is most likely, slider 222 is located in the section with the largest slide rail radius (R2), and the lever arm of adjusting end 212 reaches its maximum value; thereafter, as the angle continues to increase, slider 222 enters the section with a decreasing slide rail radius, and the lever arm gradually shortens again until it becomes R1—that is, the equivalent tension transmitted to the tendon is mechanically "unloaded." In the neutral or extreme abduction positions, L2 is smaller and F1 is larger, providing sufficient fixation stability.

[0042] This ability to precisely control the lever arm change through the cam profile ensures the successful realization of the "nonlinear inverse correlation relationship." It allows the device's mechanical response characteristics to be "tailor-made" to adapt to the complex physiological needs of different joints and tendons.

[0043] Please see Figure 1 and Figure 6 In this embodiment, the graft connector 230 includes a guide wheel 231 and a flexible traction line 232.

[0044] The guide wheel 231 is a small, freely rotatable wheel mounted on the connecting end 211 of the lever arm 210 via a miniature bearing or a smooth shaft. Its function is to change the direction of force and reduce friction.

[0045] The flexible traction suture 232 uses medical high-strength sutures, such as ultra-high molecular weight polyethylene sutures. The traction suture has two ends: the first end is used to connect to the graft, for example, by fixing it to the tendon rupture end through braided sutures; the second end is led out from the graft, first passing around the guide wheel 231 of the lever arm 210 connecting end 211, changing its direction, and finally being fixed at a predetermined position on the bone fixation base 100.

[0046] This structure, consisting of a guide wheel 231 and a flexible traction line 232, allows for the transmission of tension through the flexible traction line 232 when the graft is subjected to tension. Because the traction line bypasses the freely rotating guide wheel 231, friction between the traction line and the guide wheel 231 is minimized, ensuring that the tension on the graft is transmitted to the connection end 211 of the lever arm 210 with virtually no loss. More importantly, the guide wheel 231 allows the direction of the traction line to change flexibly according to joint movement. Regardless of the direction of tendon traction, the force can effectively act along the traction line on the tangent of the guide wheel 231, thereby driving the lever arm 210 to rotate. This structure is simple, reliable, and entirely within the operating range of existing surgical instruments, making it easy to implement clinically.

[0047] Please see Figure 1 and Figure 5 In practical implementation, a hook 233 can be provided at the first end of the flexible traction line 232 (i.e., the end connected to the transplant). This hook 233 can be made of materials such as titanium alloy or PEEK, and has a hook-shaped structure and a tail that connects to the traction line.

[0048] During surgery, the surgeon can pre-place the flexible traction suture 232 and its hook 233 in the surgical area. When it is necessary to connect the graft, the surgeon simply inserts the pre-set suture loop or special suture from the graft into the hook 233, eliminating the need for cumbersome threading and knotting. This "plug-and-play" connection method greatly simplifies the surgical procedure and shortens the operation time, especially in arthroscopic surgery where the space is confined, its convenience is particularly outstanding. At the same time, the hook 233 structure can also be designed with a self-locking function to ensure that it will not accidentally come loose during postoperative movement.

[0049] Multiple annular grooves arranged parallel to each other along the axial direction (i.e., the thickness direction of the wheel) can be provided on the outer peripheral surface of the guide wheel 231. These grooves are like multiple parallel "tracks".

[0050] In surgeries such as rotator cuff repair, surgeons often use multi-strand sutures to enhance fixation strength (e.g., double-row sutures). These multi-strand sutures can be individually housed in different annular grooves, each following its own path without interference. This ensures that each suture slides smoothly on the guide wheel 231, preventing tangling, jamming, or friction within a single groove. This design guarantees that the combined force of the multi-strand sutures is smoothly and evenly transmitted to the lever arm 210, improving the device's applicability and stability in complex repair procedures.

[0051] Please see Figure 1In a preferred embodiment, a dedicated traction fixation post 234 is provided on the outer wall of the bone fixation base 100. This fixation post typically has a threading hole or a winding groove. After the second end of the flexible traction wire 232 passes around the guide wheel 231, it is tightened and finally fixed on this traction fixation post 234, which can be locked by knotting, crimping, or snapping.

[0052] Please see Figure 1 and Figure 6 In this embodiment, the preload adjustment knob 240 includes a friction plate 241 and an adjustment screw 242. The friction plate 241 is an annular or semi-annular gasket with a high coefficient of friction, which is directly placed on the end of the rotating shaft 213 or wrapped around the journal of the rotating shaft 213.

[0053] The adjusting screw 242 is a rod with external threads. Its middle part engages with the internal threaded hole on the bone fixation base 100 to achieve axial movement when screwed. The end of the adjusting screw 242 is rotatably connected to the friction plate 241 in a manner that does not disengage it (for example, the end has an annular boss that engages in the annular groove of the friction plate 241).

[0054] When the surgeon rotates the adjusting screw 242 during the procedure, the screw will move axially (forward or backward) due to the threaded engagement between the screw and the base. This axial movement will push or pull the friction plate 241, thereby changing the clamping force of the friction plate 241 on the rotating shaft 213. The greater the clamping force, the greater the frictional damping when the rotating shaft 213 rotates; and vice versa.

[0055] Through this precise "screw-friction plate 241" mechanism, surgeons can achieve stepless and precise adjustment of the friction damping of the rotating shaft 213. This is crucial for setting the ideal initial tension during surgery: if the damping is set too low, the device may be too sensitive, leading to tendon relaxation; if the damping is set too high, the device may be sluggish and lose its adjusting function. This structure allows surgeons to find an optimal balance point based on the specific conditions such as tendon tension and tissue quality observed during surgery, truly realizing the clinical value of "adjustability".

[0056] Please see Figure 1 Furthermore, this invention provides a method for tension adjustment using the aforementioned device, the method comprising the following steps: Step 1: Implantation of bone fixation base 100: Under arthroscopic monitoring, a special tool is used to fix the bone fixation base 100 to a predetermined bone surface on the glenoid fossa or the humeral head. Depending on the bone condition, the self-tapping fixation part 120 can be screwed into the bone, or a press-fit anchor can be hammered into a pre-drilled bone hole to ensure that the base body 110 fits firmly and securely against the bone surface without any wobbling.

[0057] Step 2: Graft Attachment and Initial Tension Setting: The graft connector 230 is connected to the graft to be repaired. Specifically, the hook 233 with the flexible traction suture 232 attached can be hung on the graft, or the traction suture can be sutured to the graft. Subsequently, the physician operates the pretension adjustment knob 240: rotating the adjustment screw 242 causes it to move axially, changing the clamping force on the rotating shaft 213 by pushing or pulling the friction plate 241, thereby setting a suitable frictional damping. This step sets the initial resting tension on the graft when the joint is in a neutral position, establishing the starting point for the entire adjustment system.

[0058] Step 3: Postoperative dynamic adjustment: Post-operatively, as the patient undergoes rehabilitation exercises, the joint begins to move. When joint movement causes changes in the tension on the graft, this change drives the lever arm 210 to rotate around its axis 213 via the graft connector 230 (flexible traction cable 232 and guide wheel 231). Simultaneously, the lever arm 210 rotates, and its adjusting end 212 (elastic telescopic rod) drives the slider 222, which is hinged to it, to slide along the curved slide rail 221. Because the curved slide rail 221 is designed as a cam profile with a variable radius, the position of the slider 222's support point on the adjusting end 212 changes continuously at different sliding positions, thus dynamically altering the lever arm length of the adjusting end 212. According to the lever principle, with the force point of the connecting end 211 essentially fixed, the change in the lever arm of the adjusting end 212 directly leads to a change in the equivalent tension of the connecting end 211. By pre-setting the cam profile, this variation pattern is precisely such that when the joint moves to certain specific angles, the equivalent tension at the connecting end 211 automatically decreases due to the increase in lever arm, forming a "non-linear inverse correlation" between the equivalent tension and the rotation angle. In this way, regardless of the joint's movement, the tension on the graft can be dynamically and passively maintained within a physiological range most favorable for healing, effectively avoiding stress concentration at specific angles and creating the optimal mechanical environment for tendon-bone healing.

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An intraoperative tension-adjustable graft fixation device, characterized in that, include: Bone fixation base, which can be fixedly connected to the bone surface; Tension adjustment assembly, movably connected to the bone fixation base, the tension adjustment assembly comprising: A lever arm, the middle part of which is pivotally connected to the bone fixation base via a pivot, and the two ends of the lever arm are a connecting end and an adjusting end, respectively; A sliding torque converter is disposed between the adjusting end of the lever arm and the bone fixation base, and is used to change the lever arm length of the lever arm; A graft connector is provided at the connecting end of the lever arm for connecting to the graft; A preload adjustment knob is connected to the end of the rotating shaft and extends to the outside of the bone fixation base, used to adjust the frictional damping of the rotating shaft; The lever arm tends to rotate around the pivot under the tension transmitted by the graft, and the sliding torque converter can change the support position according to the rotation angle of the lever arm, so that the equivalent tension at the graft connector has a non-linear inverse correlation with the rotation angle of the lever arm.

2. The intraoperative tension-adjustable graft fixation device according to claim 1, characterized in that, The bone fixation base includes: Base body; A fixation part, disposed on the bottom surface of the base body, is used for implantation into the bone; the fixation part is a screw rod with self-tapping threads or a press-fit anchor. A receiving cavity is provided at the top of the base body for accommodating the adjusting end and the sliding torque converter.

3. The intraoperative tension-adjustable graft fixation device according to claim 1, characterized in that, The sliding torque converter includes: A curved slide rail is fixed to the bone fixation base, and the center of the trajectory of the curved slide rail is located on the axis of the rotating shaft; and The slider is slidably disposed within the curved slide rail, and the connecting end is an elastic telescopic rod that is hinged to the slider.

4. The intraoperative tension-adjustable graft fixation device according to claim 3, characterized in that, The radius of the curved slide rail changes continuously in the circumferential direction to form the cam profile surface.

5. The intraoperative tension-adjustable graft fixation device according to claim 1, characterized in that, The graft connector includes: A guide wheel is rotatably mounted on the connecting end; A flexible traction wire, the first end of which is used to connect the graft, and the second end of which passes around the guide wheel and is fixed to the bone fixation base.

6. The intraoperative tension-adjustable graft fixation device according to claim 5, characterized in that, The graft connector also includes a hook disposed at the first end of the flexible traction line.

7. The intraoperative tension-adjustable graft fixation device according to claim 5, characterized in that, The outer periphery of the guide wheel is provided with multiple annular grooves arranged along the axial direction, which are used to accommodate multiple strands of the flexible traction wire.

8. The intraoperative tension-adjustable graft fixation device according to claim 7, characterized in that, The bone fixation base is provided with a traction fixation column, and the second end of the flexible traction line is fixed to the traction fixation column.

9. The intraoperative tension-adjustable graft fixation device according to claim 1, characterized in that, The preload adjustment knob includes a friction plate and an adjustment screw. The friction plate is mounted on the rotating shaft. The middle part of the adjustment screw is threaded to the bone fixation base. The end of the adjustment screw is rotatably connected to the friction plate. Rotating the adjustment screw increases the clamping force that presses the friction plate against the rotating shaft.

10. A method for tension-adjustable graft fixation using the intraoperative tension-adjustable graft fixation device according to any one of claims 1-9, characterized in that, Includes the following steps: Fix the bone fixation base to the bone surface; Connect the graft connector to the graft, rotate the preload adjustment knob, and adjust the screw to drive the friction plate to change the clamping force on the rotating shaft, thus setting the initial tension; During postoperative joint movement, the graft drives the lever arm to rotate around the axis via the graft connector; The lever arm adjustment end drives the slider hinged to it to slide along the curved slide rail. The variable radius cam profile of the curved slide rail changes the support position of the slider on the adjustment end, thereby dynamically adjusting the lever arm length. By utilizing the lever principle, the equivalent tension at the graft connector is non-linearly inversely correlated with the rotation angle of the lever arm, thereby dynamically maintaining the graft tension within a preset range.

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