Adjustable fixed retraction device for knee arthroplasty and method of use

Abstract

This invention belongs to the field of medical device technology, specifically relating to an adjustable fixation and retraction device and its usage method for knee replacement surgery. It includes two supporting components, each comprising a guide rail with a horizontal bar slidably connected to it. A locking mechanism is located at one end of the horizontal bar near the guide rail, and a first vertical bar is fixedly mounted at the other end of the horizontal bar. A second vertical bar is fixedly mounted at the end of the guide rail away from the horizontal bar. Hoffman hooks are fixedly mounted at the lower ends of both the first and second vertical bars. These Hoffman hooks are used to hook the tibia and femur, respectively. This invention, by sliding the horizontal bar on the guide rail and using the locking mechanism, allows for stepless or graded adjustment of the distance between the first and second vertical bars on the same supporting component. The surgeon can quickly adjust the lateral span of the two Hoffman hooks according to the actual width of the patient's tibial plateau or femoral condyle, ensuring stable hooking at the optimal bony attachment point.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to an adjustable fixation and distraction device and its usage method used in knee replacement surgery. Background Technology

[0002] Total knee arthroplasty (TKA) is an effective treatment for end-stage knee joint disease. Adequate surgical visualization during the procedure is crucial for ensuring precise prosthesis placement and preventing soft tissue damage. Therefore, various retraction devices are widely used clinically to open the gap between the tibia and femur, exposing deep structures such as the posterior chamber of the knee joint and the attachment points of the collateral ligaments.

[0003] Currently, commonly used knee joint surgery retraction devices are mainly divided into two categories. One category is fixed retractors, such as Z-shaped retractors and Hoffman retractors. These have a simple structure but require an assistant to hold them, which not only consumes manpower but also results in unstable traction force, making them prone to slippage or soft tissue injury due to fatigue. The other category is mechanical fixed retractors, such as Lomboard retractors or rack and pinion retractors. These connect two support arms through a crossbar and use a rack or screw mechanism to achieve lateral or longitudinal retraction.

[0004] However, existing mechanical retractors still have the following shortcomings when applied to knee replacement surgery: First, the lateral span adjustment capability of a single support arm is limited. The two hooks of the existing device are usually fixed at both ends of the same support arm, and the distance between them cannot be infinitely or finely adjusted according to the actual width of the patient's tibial plateau or femoral condyle due to differences in body size. This results in the hooks not being able to stably hook onto the optimal bony attachment point and are prone to displacement during surgery.

[0005] Second, there is a lack of flexibility in changing the surgical field shape during surgery. In standard medial approach knee arthroplasty, when exposing the lateral space or posterior joint capsule, it is often necessary to adjust the two support arms from a parallel to a non-parallel state to accommodate irregular incision shapes or avoid soft tissue obstruction. However, the crossbars of existing retractors are mostly rigidly connected, and the two support arms are always in a parallel state, which cannot flexibly change the angle during surgery, thus limiting the dynamic exposure of the surgical field.

[0006] Third, the adjustment and locking operations are cumbersome. Most devices require multiple independent locking mechanisms for lateral expansion and longitudinal tension adjustment, which need to be tightened with special tools during the operation. This is time-consuming, and the complex steps in a sterile environment affect the smoothness of the operation.

[0007] Fourth, the height adjustment lacks personalization. Because patients' knee joint soft tissue thickness and joint space size vary, the height of the hooks in existing devices is mostly a fixed value, which cannot be adaptively adjusted according to the incision location and soft tissue thickness. This can easily cause excessive traction or compression of important posterior blood vessels and nerve structures by the hooks.

[0008] Therefore, there is an urgent need to provide a traction device for knee replacement surgery that can achieve adjustable lateral span, flexible change of support arm angle, and convenient locking operation, in order to solve the problems of insufficient surgical field exposure, cumbersome operation, and high risk of tissue damage in the existing technology. Summary of the Invention

[0009] This invention addresses the aforementioned problems by providing an adjustable fixation and retraction device and its usage method for knee replacement surgery, thereby resolving the issues of insufficient surgical field exposure, cumbersome operation, and high risk of tissue damage in existing technologies.

[0010] To achieve the above objectives, the present invention employs the following technical solution: An adjustable fixation and retraction device for knee replacement surgery includes two supporting components. Each supporting component includes a guide rail, on which a crossbar is slidably connected. The crossbar is positioned outside the guide rail so that it slides above the guide rail. A plug-in locking component is located at one end of the crossbar near the guide rail. This plug-in locking component passes through the crossbar and can be selectively inserted into any arc-shaped locking position to achieve relative locking between the crossbar and the guide rail. A vertical rod is fixedly mounted at the other end of the crossbar. A second vertical rod is fixedly installed at the end of the rail furthest from the horizontal bar. Hoffman hooks are fixedly installed at the lower ends of both the first and second vertical rods. The Hoffman hooks at the lower ends of the first and second vertical rods are used to hook the tibia and femur, respectively. The middle parts of the two first and two second vertical rods are connected by adjusting components. A sliding locking component is provided between the adjusting component and the first and second vertical rods. The adjusting component is used to adjust the relative distance and angle between the two supporting components.

[0011] Furthermore, the insertion and locking component includes a locking block, a top pin fixedly mounted on the locking block, a spring sleeved on the outside of the top pin, the lower end of the spring fixedly mounted on the upper end of the locking block, a handle fixedly mounted on the upper end of the top pin, a base provided on the crossbar, a limiting sleeve provided on the base, the inner diameter of the limiting sleeve being smaller than the outer diameter of the spring, the upper end of the spring contacting the lower end face of the limiting sleeve, the limiting sleeve slidingly connected to the top pin, a plurality of arc-shaped locking positions evenly arranged on the guide rail, the locking block corresponding to the arc-shaped locking positions, and the distance between the first vertical rod and the second vertical rod being adjusted by pulling the handle to achieve relative displacement between the guide rail and the crossbar, and the locking block locking into the arc-shaped locking positions under the action of the spring.

[0012] Furthermore, the sliding locking component includes a slider, which is slidably connected to a first vertical rod. Two locking blocks are slidably disposed at both ends inside the slider. These locking blocks are connected to the center of the slider by bolts. One end of the bolt is provided with an adjusting handle, which is rotated to lock and release the two locking blocks. A fixed cylinder is disposed at the end of the slider away from the first vertical rod, and a locking cap is disposed on the outside of the fixed cylinder. Both ends of the adjusting component are disposed inside the fixed cylinder and are fixedly connected by the locking caps. The fixed cylinder and the slider are integrally formed.

[0013] Furthermore, the adjusting component includes two adjusting rods. One end of each adjusting rod is respectively disposed inside two fixed cylinders and fixed by locking caps. The other ends of the two adjusting rods pass through an annular handle. The annular handle has threaded holes at positions corresponding to the adjusting rods. The adjusting rods are adjusted by rotating the annular handle. A fixing nut is provided at the end of the adjusting rod near the annular handle.

[0014] Furthermore, the adjusting rod is configured as an "L" shape, with the long rod of the adjusting rod in contact with the annular handle, and the short rod of the adjusting rod being engaged with the fixed cylinder. A cylindrical locking block is provided at the end of the short rod of the adjusting rod, and the cylindrical locking block corresponds to the fixed cylinder. The diameter of the through hole of the locking cap is smaller than the outer diameter of the cylindrical locking block. The locking cap is sleeved on the adjusting rod, and the locking cap is configured as a constricted structure.

[0015] A method of using an adjustable fixation and distraction device in knee replacement surgery includes the following steps: Step 1: Before the operation, according to the size of the patient's knee, the guide rail and crossbar are clamped to the corresponding size to achieve lateral fixation between the guide rail and the crossbar. The guide rail and crossbar are fixed by pulling the handle to achieve longitudinal fixation of the entire support component. The two support components are assembled in the same way. Step 2: Fix the sliders at the same horizontal position of vertical rod 1 and vertical rod 2 using the adjusting handles. At the same time, connect the two adjusting rods to a ring handle with threads, and then fix the adjusting rods with fixing nuts. The adjusting rods are respectively clamped in the corresponding fixing cylinders and fixed with locking caps. Step 3: Fix the two support components with a circular grip according to the size of the patient's knee flexion. Then, place the Hoffman hooks at the bottom of the two support components into the tibia and femur respectively to expose the tibia and femur. Step 4: After placing the device under the patient's knee, loosen the locking cap to allow the two support components to rotate relative to the sliding locking component, achieving parallel or intersecting placement. Compared with the prior art, the present invention has the following advantages: 1. This invention achieves stepless or graded adjustment of the distance between the first and second vertical rods on the same support component by sliding a crossbar on the guide rail and using a locking component. The surgeon can quickly adjust the lateral span of the two Hoffman hooks according to the actual width of the patient's tibial plateau or femoral condyle, so that they are stably hooked at the optimal bony attachment point, avoiding hook slippage or unstable hooking due to span mismatch. Compared with existing fixed span retractors, this invention significantly improves the device's adaptability to body shape and intraoperative stability.

[0016] 2. This invention utilizes the fixed cylinder and locking cap structure in the sliding locking component to allow the two supporting components to rotate relative to the adjusting component. During the operation, the locking cap can be loosened at any time as needed to adjust the two supporting components from a parallel state to an intersecting state or to a certain angle, in order to adapt to irregular surgical incision shapes, avoid soft tissue obstruction, or expose joint spaces in different directions. This flexible ability to change between parallel and intersecting states is not available in existing rigid crossbar-connected retractors, significantly enhancing the dynamic exposure capability of the surgical field, and is especially suitable for exposing the lateral space or posterior joint capsule in the medial approach of the knee joint.

[0017] 3. This invention uses a plug-in locking component with a handle, spring, top pin, and arc-shaped locking position to lock or release the guide rail and crossbar. The surgeon only needs to pull or release the handle to complete the operation, without any special tools such as wrenches or screwdrivers. It can be completed with one hand, which greatly simplifies the intraoperative adjustment steps. At the same time, the sliding locking component adopts a bolt and adjustment handle structure. By turning the adjustment handle, the slider can be locked and slid on the vertical rod. The operation is intuitive and time-saving, and meets the operation requirements in a sterile surgical environment.

[0018] 4. This invention, by setting a sliding locking component in the middle of the first and second vertical rods, allows the installation height of the adjustment component to be freely adjusted according to the thickness of the soft tissue of the patient's knee joint and the incision location. The surgeon can fix the adjustment component at the most suitable vertical height, making the direction of the traction force of the Hoffman retractor on the tibia and femur more reasonable, avoiding excessive compression or traction of posterior blood vessels, nerves or soft tissues due to improper fixation height, and reducing the risk of iatrogenic injury.

[0019] 5. The adjustment component of this invention adopts a structure of two L-shaped adjustment rods, a ring handle, and a fixing nut. The two adjustment rods pass through the ring handle and are threadedly connected to it. The surgeon only needs to rotate the ring handle to adjust the effective length of the two adjustment rods simultaneously, thereby changing the distance between the two support components in a synchronous manner and achieving balanced adjustment of the retraction force on both sides. After adjustment, it is fixed by the fixing nut. Compared with the cumbersome operation of adjusting the left and right sides separately in the prior art, this invention significantly improves the efficiency of intraoperative adjustment and ensures the symmetry and stability of the retraction on both sides.

[0020] 6. The insertion and locking component of this invention uses a spring-preloaded locking block that engages with multiple arc-shaped locking positions on the guide rail. After locking, it has a clear locking feel and strong anti-slip capability. The sliding locking component clamps the vertical rod with two opposing blocks, resulting in a large contact area and stable locking. The cylindrical block at the end of the adjusting rod engages with the fixing cylinder and locking cap, effectively preventing the adjusting rod from loosening or rotating during use. Each locking mechanism is independent and complementary, ensuring that the device remains stable under continuous traction during surgery and does not loosen or shift.

[0021] 7. The invention has a simple overall structure, requires no complex processing technology, and has low manufacturing costs. Each component is detachable and assembleable, facilitating preoperative disinfection and postoperative cleaning. Furthermore, it contains no electronic components or precision sensors, ensuring high reliability. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the parallel configuration of the present invention; Figure 2 This is a schematic diagram of the intersecting structure of the present invention; Figure 3 This is a schematic diagram of the structure of the support component of the present invention; Figure 4 This is a schematic diagram of the crossbar structure of the present invention; Figure 5 This is a cross-sectional view of the crossbar and guide rail of the present invention; Figure 6 This is a schematic diagram of the insertion and removal locking component of the present invention; Figure 7 This is a schematic diagram of the sliding locking component of the present invention; Figure 8 This is a schematic diagram of the structure of the fixed cylinder of the present invention; Figure 9 This is a schematic diagram of the structure of the adjusting component of the present invention; In the diagram, the components are: support component 1, guide rail 101, crossbar 102, first vertical bar 103, second vertical bar 104, arc-shaped locking position 105, plug-in locking component 2, locking block 201, top pin 202, spring 203, handle 204, base 205, limit sleeve 206, Hoffman hook 3, adjusting component 4, adjusting rod 401, ring handle 402, cylindrical locking block 403, sliding locking component 5, slider 501, first locking block 502, bolt 503, adjusting handle 504, fixing cylinder 505, and locking cap 506. Detailed Implementation

[0023] To further illustrate the technical solution of the present invention, the present invention will be further described below through embodiments.

[0024] like Figure 1-9As shown, an adjustable fixation and retraction device for knee replacement surgery includes two support components 1. Each support component 1 includes a guide rail 101 with a plurality of arc-shaped locking positions 105 evenly arranged on it. A crossbar 102 is slidably connected to the guide rail 101, located above the guide rail 101. A plug-in locking component 2 is provided at one end of the crossbar 102 near the guide rail 101. The plug-in locking component 2 passes through the crossbar 102 and can be selectively inserted into any one of the arc-shaped locking positions 105. A vertical rod 103 is fixedly installed at the other end of the crossbar 102. The guide rail 101 is located away from the crossbar 102. A second vertical rod 104 is fixedly installed at one end. Hoffman hooks 3 are fixedly installed at the lower ends of both the first vertical rod 103 and the second vertical rod 104. The Hoffman hooks 3 at the lower ends of the first vertical rod 103 and the second vertical rod 104 are used to hook the tibia and femur, respectively. The middle parts of the two first vertical rods 103 and the two second vertical rods 104 are connected by adjusting components 4. The adjusting components 4 are connected to the first vertical rod 103 and the second vertical rod 104 by sliding locking components 5, and can slide and rotate along the first vertical rod 103 and the second vertical rod 104 to change the relative lateral distance and included angle between the two supporting components 1.

[0025] like Figure 5 and Figure 6 As shown, the insertion and locking component 2 includes a locking block 201, a top pin 202 fixedly mounted on the locking block 201, a spring 203 sleeved on the outside of the top pin 202, the lower end of the spring 203 fixedly mounted on the upper end of the locking block 201, a handle 204 fixedly mounted on the upper end of the top pin 202, a base 205 provided on the crossbar 102, and a limiting sleeve 206 provided on the base 205, the inner diameter of the limiting sleeve 206 being smaller than that of the spring 203. The outer diameter of the spring 203 is such that the upper end of the spring 203 abuts against the lower end face of the limiting sleeve 206, the limiting sleeve 206 is slidably connected to the top pin 202, the locking block 201 corresponds to the arc-shaped locking position 105, and the relative displacement of the guide rail 101 and the crossbar 102 is achieved by pulling the handle 204 to adjust the distance between the first vertical rod 103 and the second vertical rod 104. The locking block 201 is locked into the arc-shaped locking position 105 under the action of the spring 203.

[0026] like Figure 7As shown, the sliding locking component 5 includes a slider 501, which is slidably connected to a first vertical rod 103. Two locking blocks 502 are slidably disposed at both ends inside the slider 501. The locking blocks 502 are connected to the center of the slider 501 via bolts 503. One end of the bolt 503 is provided with an adjusting handle 504. Rotating the adjusting handle 504 allows the locking and unlocking of the two locking blocks 502 to be achieved. A fixing cylinder 505 is disposed at the end of the slider 501 away from the first vertical rod 103. A locking cap 506 is disposed on the outside of the fixing cylinder 505. Both ends of the adjusting component 4 are respectively disposed inside the fixing cylinder 505 and are fixedly connected via the locking caps 506. The fixing cylinder 505 and the slider 501 are integrally formed. The bolt 503 and the locking blocks 502 are threaded together. Rotating the adjusting handle causes the two locking blocks to move towards the center or sides.

[0027] like Figure 9 As shown, the adjusting component 4 includes two adjusting rods 401. One end of each adjusting rod 401 is respectively disposed within two fixed cylinders 505 and fixed by locking caps 506. The other ends of the two adjusting rods 401 pass through an annular handle 402. The annular handle 402 has threaded holes corresponding to the positions of the adjusting rods 401. Adjustment of the adjusting rods 401 is achieved by rotating the annular handle 402. A fixing nut is provided at the end of the adjusting rod 401 near the annular handle 402. The adjusting rod 401 is configured as an "L" shape. The long rod of the adjusting rod 401 contacts the annular handle 402, and the short rod of the adjusting rod 401 is engaged with the fixed cylinder 505. A cylindrical locking block 403 is provided at the end of the short rod of the adjusting rod 401. The cylindrical locking block 403 corresponds to the fixed cylinder 505. The diameter of the through hole of the locking cap 506 is smaller than the outer diameter of the cylindrical locking block 403. The locking cap 506 is sleeved on the adjusting rod 401, and the end of the locking cap 506 has a constricted structure.

[0028] A method of using an adjustable fixation and distraction device in knee replacement surgery includes the following steps: Step 1: Before the operation, according to the size of the patient's knee, the guide rail 101 and the crossbar 102 are clamped in the corresponding size to achieve the lateral fixation between the guide rail 101 and the crossbar 102. The guide rail 101 and the crossbar 102 are fixed by pulling the handle 204 to achieve the longitudinal fixation of the entire support component 1. The two support components 1 are assembled in the same way. Step 2: Fix the slider 501 at the same horizontal position of vertical rod 103 and vertical rod 104 using the adjusting handle 504. At the same time, thread the two adjusting rods 401 to a ring handle 402, and then fix the adjusting rods 401 with fixing nuts. The adjusting rods 401 are respectively clamped in the corresponding fixing cylinders 505 and fixed by locking caps 506, which are sleeved on the adjusting rods. Step 3: Fix the two support components 1 with the ring handle 402 according to the size of the patient's knee flexion. Then, put the Hoffman hooks 3 at the bottom of the two support components 1 into the tibia and femur respectively to expose the tibia and femur. Step 4: After the device is placed under the patient's knee, loosen the locking cap 506 to allow the two support parts 1 to rotate relative to the sliding locking part 5, so as to achieve parallel or intersecting placement.

[0029] The foregoing has shown and described the main features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0030] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An adjustable fixation and distraction device for use in knee replacement surgery, characterized in that: The device includes two support components (1). Each support component (1) includes a guide rail (101). The guide rail (101) has a plurality of arc-shaped locking positions (105) evenly arranged on it. A crossbar (102) is slidably connected to the guide rail (101). The crossbar (102) is located outside the guide rail (101) so that it slides above the guide rail (101). A plug-in locking component (2) is provided at one end of the crossbar (102) near the guide rail (101). The plug-in locking component (2) passes through the crossbar (102) and can be selectively inserted into any arc-shaped locking position (105) to achieve relative locking between the crossbar (102) and the guide rail (101). A vertical rod is fixedly installed at the other end of the crossbar (102). (103) A second vertical rod (104) is fixedly installed at one end of the guide rail (101) away from the crossbar (102). Hoffman hooks (3) are fixedly installed at the lower ends of the first vertical rod (103) and the second vertical rod (104). The Hoffman hooks (3) at the lower ends of the first vertical rod (103) and the second vertical rod (104) are used to hook the tibia and femur respectively. The middle parts of the two first vertical rods (103) and the two second vertical rods (104) are connected by adjusting components (4). A sliding locking component (5) is provided between the adjusting component (4) and the first vertical rod (103) and the second vertical rod (104). The relative distance and angle between the two supporting components (1) are adjusted by the adjusting component (4).

2. The adjustable fixation and distraction device for knee replacement surgery according to claim 1, characterized in that: The insertion and extraction locking component (2) includes a locking block (201), a top pin (202) is fixedly installed on the locking block (201), a spring (203) is sleeved on the outside of the top pin (202), the lower end of the spring (203) is fixedly installed on the upper end of the locking block (201), a handle (204) is fixedly installed on the upper end of the top pin (202), a base (205) is provided on the crossbar (102), a limit sleeve (206) is provided on the base (205), and the inner diameter of the limit sleeve (206) is smaller than that of the spring (203). The outer diameter of the spring (203) is such that the upper end of the spring (203) contacts the lower end face of the limiting sleeve (206), the limiting sleeve (206) is slidably connected to the top pin (202), the locking block (201) corresponds to the arc-shaped locking position (105), and the relative displacement of the guide rail (101) and the crossbar (102) is achieved by pulling the handle (204) to adjust the distance between the first vertical rod (103) and the second vertical rod (104). The locking block (201) is locked into the arc-shaped locking position (105) under the action of the spring (203).

3. The adjustable fixation and distraction device for knee replacement surgery according to claim 1, characterized in that: The sliding locking component (5) includes a slider (501), which is slidably connected to a first vertical rod (103). Two first locking blocks (502) are slidably arranged at both ends inside the slider (501). The first locking blocks (502) are connected to the center of the slider (501) by bolts (503). One end of the bolt (503) is provided with an adjusting handle (504). By rotating the adjusting handle (504), the two first locking blocks (502) can be locked and released. A fixed cylinder (505) is provided at the end of the slider (501) away from the first vertical rod (103). A locking cap (506) is provided on the outside of the fixed cylinder (505). The two ends of the adjusting component (4) are respectively arranged inside the fixed cylinder (505) and are fixedly connected by the locking cap (506). The fixed cylinder (505) and the slider (501) are integrally formed.

4. The adjustable fixation and distraction device for knee replacement surgery according to claim 3, characterized in that: The adjusting component (4) includes two adjusting rods (401). One end of each adjusting rod (401) is respectively set in two fixed cylinders (505) and fixed by locking caps (506). The other ends of the two adjusting rods (401) pass through an annular handle (402). The annular handle (402) is provided with threaded holes at positions corresponding to the adjusting rods (401). The adjusting rods (401) are adjusted by rotating the annular handle (402). A fixing nut is provided at the end of the adjusting rod (401) near the annular handle (402).

5. An adjustable fixation and distraction device for knee replacement surgery according to claim 4, characterized in that: The adjusting rod (401) is set in an "L" shape. The long rod of the adjusting rod (401) contacts the annular handle (402). The short rod of the adjusting rod (401) is engaged with the fixed cylinder (505). A cylindrical locking block (403) is provided at the end of the short rod of the adjusting rod (401). The cylindrical locking block (403) corresponds to the fixed cylinder (505). The diameter of the through hole of the locking cap (506) is smaller than the outer diameter of the cylindrical locking block (403). The locking cap (506) is sleeved on the adjusting rod (401). The locking cap (506) is set in a constricted structure.

6. A method of using an adjustable fixation and retraction device for knee replacement surgery according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Before the operation, according to the size of the patient's knee, the guide rail (101) and the crossbar (102) are clamped to the corresponding size to achieve the lateral fixation between the guide rail (101) and the crossbar (102). The guide rail (101) and the crossbar (102) are fixed by pulling the handle (204) to achieve the longitudinal fixation of the entire support component (1). The two support components (1) are assembled in the same way. Step 2: Fix the slider (501) at the same horizontal position of the first vertical rod (103) and the second vertical rod (104) through the adjusting handle (504). At the same time, thread the two adjusting rods (401) to a ring handle (402), and then fix the adjusting rods (401) through the fixing nut. The adjusting rods (401) are respectively clamped in the corresponding fixing cylinder (505) and fixed by the locking cap (506). Step 3: Fix the two support components (1) with the ring handshake (402) according to the size of the patient's knee flexion. Then, place the Hoffman hooks (3) at the bottom of the two support components (1) into the tibia and femur respectively to expose the tibia and femur. Step 4: After the device is placed on the patient's knee, loosen the locking cap (506) to allow the two support parts (1) to rotate relative to the sliding locking part (5) to achieve parallel or intersecting placement.

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