Variable stiffness external fixation device for accelerating healing of lower limb fracture

Abstract

The invention discloses a variable stiffness external fixing device for accelerating lower limb fracture healing, which comprises two oppositely arranged fixing rings, a plurality of support arms connected between the two fixing rings, and kirschner wires arranged inwards along the radial direction on the fixing rings, and is characterized in that the fixing rings are also provided with kirschner wire applied stiffness adjusting mechanisms. The rigidity change of the fixing end of the external bone fixing device can be adjusted, the structure is simple, adjustment is convenient and fast, and the rigidity adjusting requirements of different stages in the bone rehabilitation process can be better met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of orthopedic external fixation devices, in particular to a variable stiffness external fixation device for accelerating lower limb fracture healing. BACKGROUND

[0002] In the rehabilitation process of fracture patients, especially limb fracture patients, orthopedic external fixation supports are usually used to fix the fracture site to avoid secondary injury during the rehabilitation process. However, both too high fixation stiffness and too low fixation stiffness are not conducive to the growth and rehabilitation of the fracture site. Too high fixation stiffness will lead to stress shielding phenomenon, and most of the load received by the broken bone will be borne by the external fixator, and the force stimulation received by the fracture site of the broken bone will be too small, which is not conducive to the rapid healing and rehabilitation of the bone. Too low fixation stiffness will lead to unstable mechanical environment of the fracture site of the broken bone, resulting in delayed healing of the bone. Different patients have different needs for fixation stiffness corresponding to different fracture conditions, and the same patient has different needs for fixation stiffness corresponding to different stages in the fracture rehabilitation process, so it is necessary to consider adding a function of adjusting the fixation stiffness on the fixation device.

[0003] The existing orthopedic external fixation support is usually composed of two fixation rings and connecting arms connected between the fixation rings. When in use, Kirschner wires are installed on the fixation rings and fixed at both ends of the limb fracture site, and then the connecting arms with telescopic function are used to adjust the relative position of the fixation rings to keep the limb in a normal fixed growth state. The stiffness of such conventional orthopedic external fixation support cannot be adjusted, which makes it difficult to better meet the use requirements.

[0004] CN202310326669.9 has disclosed a bone external fixation auxiliary holding system, which comprises two oppositely arranged fixation rings, a bone needle mounting structure is arranged on the fixation ring, a plurality of support arms are hingedly arranged between the two fixation rings, and each support arm is provided with a variable stiffness joint capable of adjusting the axial stiffness of the support arm. The application has the advantages of better meeting the requirements of different periods of growth and healing of the fracture site and being more conducive to the rehabilitation and growth of the fracture site. However, it still has the following defects: 1. The support arm needs to bear the function of adjusting the axial length during the use of the device, and the addition of the stiffness adjustment function greatly increases the structural complexity and the inconvenience of operation of the device. 2. During the rehabilitation process of the skeleton, not only is there a need for stiffness change in the axial direction, but there is also a need for stiffness change adjustment in the swing direction. However, the existing device support arm can only adjust the axial stiffness change and cannot adjust the swing direction stiffness change, which cannot better meet the adjustment requirements of the stiffness change during the rehabilitation process of the skeleton. SUMMARY

[0005] In view of the deficiencies of the prior art, the technical problem to be solved by the present application is how to provide a variable stiffness external fixation device for accelerating lower limb fracture healing, which can adjust the stiffness change, has simple structure and is convenient to adjust, so as to better meet the stiffness adjustment requirements in different stages of the bone rehabilitation process.

[0006] In order to solve the above technical problems, the present application adopts the following technical scheme: The variable stiffness external fixation device for accelerating lower limb fracture healing comprises two oppositely arranged fixing rings, a plurality of support arms are connected and arranged between the two fixing rings, and Kirschner wires are arranged on the fixing rings and arranged radially inward, characterized in that a Kirschner wire applied stiffness adjusting mechanism is further arranged on the fixing ring.

[0007] In this way, the Kirschner wire applied stiffness adjusting mechanism can be used to adjust and change the Kirschner wire applied stiffness, so that the stiffness (flexibility) requirements of the bone in the axial elongation direction and the stiffness (flexibility) requirements in the swing direction can be realized by the deflection of the Kirschner wire. Therefore, the stiffness adjustment requirements in the bone rehabilitation process can be better met, and the bone rehabilitation growth is more beneficial.

[0008] Further, an axial length adjusting mechanism is further arranged on the support arm. In this way, the axial length of the support arm can be adjusted when needed.

[0009] Further, the axial length adjusting mechanism is a lead screw and nut mechanism, the lead screw and the nut are coaxially arranged with the support arm in the lead screw and nut mechanism, the nut is fixed to one end of the support arm, and the lead screw is installed on the motor output shaft fixed to the other end of the support arm and cooperates with the nut to realize adjustment. In this way, the structure is simple, and the adjustment is convenient and reliable.

[0010] Further, the two ends of the support arm are respectively hinged to the mounting positions which are outwardly protruded and uniformly arranged on the outer periphery of the fixing ring. In this way, the adjustment of the spatial position of the fixing ring can be conveniently realized.

[0011] Further, the support arm is six and the end portions of the support arms of the same fixing ring are two by two adjacent to form a V shape, and the V shapes formed by the support arms connected to the two fixing rings are arranged in a staggered manner.

[0012] In this way, the six support arms form six support chains, which can realize the adjustment of the three rotational degrees of freedom and the three movement degrees of freedom of the fixing ring by the axial adjustment of the support arms.

[0013] Further, the Kirschner wire is a plurality of Kirschner wires which are uniformly arranged along the circumferential direction of the fixing ring.

[0014] In this way, the fixation of the bone can be better realized.

[0015] Further, a Kirschner pin fixing seat is arranged on the fixing ring, an outer end of the Kirschner pin is fixed on the Kirschner pin fixing seat, the Kirschner pin rigidity adjusting mechanism comprises the Kirschner pin fixing seat, further comprises a Kirschner pin sliding seat, the Kirschner pin sliding seat is arranged with a first sliding hole and a Kirschner pin slidable cooperation, a reinforcing shaft parallel to the Kirschner pin is further arranged between the Kirschner pin sliding seat and the Kirschner pin fixing seat, one end of the reinforcing shaft is fixedly arranged, and the other end is slidable cooperation with a second sliding hole.

[0016] Thus, due to the existence of the reinforcing shaft, the deflection of the Kirschner pin between the Kirschner pin sliding seat and the Kirschner pin fixing seat is very low (approximately zero), the deflection of the Kirschner pin is mainly provided by the distance between the Kirschner pin sliding seat and the inner end of the Kirschner pin, so the length of the distance that the Kirschner pin can provide deflection can be adjusted by sliding the Kirschner pin sliding seat on the Kirschner pin, thereby changing the size of the deflection that the Kirschner pin can provide, and thereby realizing the adjustment of the rigidity of the Kirschner pin. Compared with the previous method of adjusting the rigidity by arranging a rigidity adjusting mechanism on the support arm, the structure is simpler and the adjustment is more convenient, and does not affect the extension adjustment of the support arm itself. At the same time, since the deflection adjustment of the Kirschner pin changes the size of the deflection angle that the Kirschner pin can provide to the inner end, this adjustment can meet the requirements of the fixed end in axial extension and circumferential deflection (because both requirements can be converted into the bending deflection of the inner end of the Kirschner pin). Moreover, the deflection size of the Kirschner pin in different directions can be adjusted according to needs (for example, the orientation of the fracture healing prescription is different), so as to realize different adjustment of the swing allowance of the device in different directions, and better meet the needs of bone healing.

[0017] Further, the first sliding hole and the Kirschner pin are gap cooperation. In this way, the sliding cooperation can be better maintained and the Kirschner pin between the Kirschner pin fixing seat and the Kirschner pin sliding seat can be prevented from participating in the deflection adjustment.

[0018] Further, the inner end of the reinforcing shaft is fixed with the Kirschner pin sliding seat, the outer end is slidable cooperation with the second sliding hole arranged on the Kirschner pin fixing seat, and the Kirschner pin fixing seat is further arranged with a reinforcing shaft fixing mechanism.

[0019] In this way, after the position of the Kirschner wire sliding seat is adjusted, the fixing of the reinforcing shaft can be realized through the reinforcing shaft fixing mechanism, and then the position of the Kirschner wire sliding seat is fixed, so that the uncertainty caused by the movement of the Kirschner wire sliding seat in the use process is avoided. At the same time, the fixing mechanism of the Kirschner wire sliding seat after the position is adjusted is changed to the Kirschner wire fixed seat, which can reduce the burden on the Kirschner wire sliding seat and avoid affecting the Kirschner wire when the reinforcing shaft is fixed. In addition, while realizing the fixation of the Kirschner wire sliding seat, the Kirschner wire and the first sliding hole are still in slidable cooperation. Since the Kirschner wire itself is a structure with large flexibility, it can provide a certain self-axial extension function, so the Kirschner wire still has the extension allowance provided by the entire length direction in the axial direction, and the extension allowance can better meet the adjustment requirement of the device fixed end to the deflection angle. In the implementation, the reinforcing shaft and the second sliding hole are in clearance fit.

[0020] Further, the reinforcing shaft fixing mechanism comprises a fastening screw hole arranged opposite to the second sliding hole, and a fastening bolt is arranged in the fastening screw hole in screwing fit.

[0021] In this way, the fastening bolt can be tightened to realize the fixation of the reinforcing shaft, and the structure is simple and convenient and fast to fix.

[0022] Further, the radial rigidity range of the Kirschner wire is 150N / mm-1200N / mm.

[0023] The application has the following characteristics: 1. Compared with other variable rigidity adjustment structure modes, the application has a large rigidity adjustment range and the ability of non-step rigidity adjustment; 2. Compared with other methods of increasing a variable rigidity joint on a connecting arm, the variable rigidity joint structure is complex and increases the overall structure weight, the application has a simple structure and is lightweight, and can avoid affecting the function of the connecting arm itself; 3. The application manually adjusts the fixing distance of the reinforcing shaft on each Kirschner wire, which is low in cost, while the traditional mechanism often uses a motor to actively drive, which increases the driving cost and is not convenient for actual use; 4. The application has a simple and compact structure, is low in processing and manufacturing cost, is high in modularization degree, is convenient to maintain, and is good in economy.

[0024] In summary, the application can adjust the rigidity change of the fixed end of the bone external fixation device, has a simple structure, is convenient to adjust, and can better meet the rigidity adjustment requirement in different stages of the bone rehabilitation process. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a structure schematic diagram in the use state of the application. DETAILED DESCRIPTION

[0026] The application will be further described in detail in combination with the specific implementation mode.

[0027] For specific implementation: see [link / reference] Figure 1 As shown, a variable stiffness external fixation device for accelerating the healing of lower limb fractures includes two opposing fixation rings 7, with multiple support arms 8 connected between the two fixation rings 7. Kirschner wires 2 are installed on the fixation rings and arranged radially inward. The device is characterized in that the fixation rings 7 are also provided with a Kirschner wire stiffness adjustment mechanism.

[0028] In this way, the stiffness adjustment mechanism of the Kirschner wires can be used to adjust and change the magnitude of the applied stiffness. Thus, the stiffness (flexibility) requirements of the bone in both the axial elongation direction and the swing direction can be achieved by the deflection of the Kirschner wires. Therefore, it can better meet the stiffness adjustment needs during bone rehabilitation and is more conducive to bone recovery and growth. Figure 1 This represents the usage state of the device of the present invention, where reference numeral 1 represents the bone to be rehabilitated.

[0029] The support arm 8 is also equipped with an axial length adjustment mechanism 9. This allows the axial length of the support arm to be adjusted when needed.

[0030] The axial length adjustment mechanism 9 is a lead screw and nut mechanism. In this mechanism, the lead screw and nut are coaxially arranged with the support arm. The nut is fixed to one end of the support arm, and the lead screw is mounted on the motor output shaft fixed to the other end of the support arm and works with the nut to achieve adjustment. This structure is simple, and the adjustment is convenient and reliable.

[0031] The support arm 8 is hinged at both ends to mounting positions that protrude outwards and are evenly distributed on the outer circumference of the fixing ring 7. This facilitates adjustment of the spatial position of the fixing ring.

[0032] Among them, there are 6 support arms 8, and the ends of the support arms of the fixed rings are adjacent to each other in a V shape. The V-shapes formed by the support arms 8 connected to the two fixed rings 7 are staggered.

[0033] In this way, the six support arms form six branches, which can adjust the three rotational degrees of freedom and three translational degrees of freedom of the fixed ring by adjusting the axial direction of the support arms.

[0034] During implementation, a pressure sensor 10 is also installed on the support arm 8 to detect the magnitude of the axial pressure on the support arm, so as to better achieve detection feedback and adjustment.

[0035] The Kirschner wires 2 are multiple ones that are evenly arranged along the circumference of the fixed ring.

[0036] This allows for better fixation of the bones.

[0037] The fixed ring 7 is provided with a Kirschner pin fixing seat 4, the outer end of the Kirschner pin 2 is fixed on the Kirschner pin fixing seat 4, the Kirschner pin rigidity adjusting mechanism comprises the Kirschner pin fixing seat 4, further comprises a Kirschner pin sliding seat 6, the Kirschner pin sliding seat is provided with a first sliding hole and a Kirschner pin slidable cooperation, a reinforcing shaft 5 parallel to the Kirschner pin is further arranged between the Kirschner pin sliding seat and the Kirschner pin fixing seat, one end of the reinforcing shaft 5 is fixedly arranged, and the other end is slidable with a second sliding hole.

[0038] Therefore, due to the existence of the reinforcing shaft, the deflection of the Kirschner pin between the Kirschner pin sliding seat and the Kirschner pin fixing seat is very low (close to zero), the deflection of the Kirschner pin is mainly provided by the distance between the Kirschner pin sliding seat and the inner end of the Kirschner pin, so that the length of the distance that the Kirschner pin can provide deflection can be adjusted by sliding the Kirschner pin sliding seat on the Kirschner pin, thereby changing the size of the deflection that the Kirschner pin can provide, and then realizing the adjustment of the rigidity of the Kirschner pin. Compared with the previous method of adjusting the rigidity by arranging a rigidity adjusting mechanism on the support arm, the structure is simpler, the adjustment is more convenient, and the telescopic adjustment of the support arm itself is not affected. At the same time, since the deflection adjustment of the Kirschner pin changes the size of the deflection angle that the Kirschner pin can provide to the inner end, this adjustment can meet the requirements of the fixed end in the axial telescopic and the circumferential deflection (because both requirements can be converted into the bending deflection of the inner end of the Kirschner pin). Moreover, the deflection size of the Kirschner pin in different directions can be adjusted according to needs (such as different orientations of fracture healing), so as to realize different adjustments of the device in different directions. The deflection size of the Kirschner pin in different directions can be adjusted according to needs (such as different orientations of fracture healing), so as to better meet the needs of bone healing.

[0039] The first sliding hole and the Kirschner pin 2 are gap fit. In this way, the sliding fit can be better maintained and the Kirschner pin between the Kirschner pin fixing seat and the Kirschner pin sliding seat can be prevented from participating in the deflection adjustment.

[0040] The inner end of the reinforcing shaft 5 is fixed with the Kirschner pin sliding seat 6, the outer end is slidable with a second sliding hole arranged on the Kirschner pin fixing seat 4, and the Kirschner pin fixing seat 4 is further provided with a reinforcing shaft fixing mechanism.

[0041] In this way, after the position of the Kirschner wire sliding seat is adjusted, the fixation of the reinforcing shaft can be realized through the reinforcing shaft fixation mechanism, and then the position of the Kirschner wire sliding seat is fixed, so as to avoid the uncertainty caused by the movement of the position of the Kirschner wire sliding seat during use. At the same time, the fixation mechanism of the Kirschner wire sliding seat after the position is adjusted is changed to the Kirschner wire fixation seat, which can reduce the burden on the Kirschner wire sliding seat and avoid affecting the Kirschner wire when the reinforcing shaft is fixed. In addition, while realizing the fixation of the Kirschner wire sliding seat, the Kirschner wire and the first sliding hole are still in slidable cooperation. Since the Kirschner wire itself is a structure with large flexibility, it can provide a certain self-axial expansion function. Therefore, the Kirschner wire still has the expansion allowance provided by the entire length direction in the axial direction, which can better meet the adjustment requirements of the device fixed end to the deflection angle. The reinforcing shaft and the second sliding hole are in clearance fit during implementation.

[0042] The reinforcing shaft fixation mechanism includes a fastening screw hole arranged opposite to the second sliding hole, and a fastening bolt 3 is arranged in the fastening screw hole in a screwing fit.

[0043] In this way, the fixation of the reinforcing shaft can be realized by tightening the fastening bolt, and the structure is simple and convenient and fast to fix.

[0044] The radial stiffness of the Kirschner wire ranges from 150 N / mm to 1200 N / mm. If the stiffness of the Kirschner wire is too low, it is difficult to meet the fixation requirements of the device, and if the stiffness is too high, it is difficult to meet the requirements of adjusting the axial expandable stiffness and the swing angle of the device fixed end through the deflection change of the Kirschner wire.

Claims

1. A variable stiffness external fixation device for accelerating lower limb fracture healing, comprising two opposing fixation rings, with a plurality of support arms connected between the two fixation rings, and Kirschner wires arranged radially inward on the fixation rings, characterized in that, The fixing ring is also equipped with a Kirschner wire stiffness adjustment mechanism.

2. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 1, characterized in that, The support arm is also equipped with an axial length adjustment mechanism.

3. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 2, characterized in that, The axial length adjustment mechanism is a lead screw and nut mechanism. In the lead screw and nut mechanism, the lead screw and nut are coaxially arranged with the support arm. The nut is fixed at one end of the support arm, and the lead screw is installed on the motor output shaft fixed at the other end of the support arm and cooperates with the nut to achieve adjustment.

4. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 1, characterized in that, The two ends of the support arm are respectively hinged to the mounting positions that protrude outwards and are evenly distributed on the outer circumference of the fixing ring.

5. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 1, characterized in that, There are 6 support arms, and the ends of the support arms connected to the fixed rings are adjacent to each other in a V-shape. The V-shapes formed by the support arms connected to the two fixed rings are staggered.

6. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 1, characterized in that, The Kirschner wires are a plurality of wires evenly arranged along the circumference of the fixed ring.

7. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 1, characterized in that, The fixing ring is provided with a Kirschner wire fixing seat, and the outer end of the Kirschner wire is fixed on the Kirschner wire fixing seat. The Kirschner wire stiffness adjustment mechanism includes the Kirschner wire fixing seat and a Kirschner wire sliding seat. The Kirschner wire sliding seat is provided with a first sliding hole and can slide with the Kirschner wire. A reinforcing shaft parallel to the Kirschner wire is also provided between the Kirschner wire sliding seat and the Kirschner wire fixing seat. One end of the reinforcing shaft is fixed, and the other end can slide with a second sliding hole.

8. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 7, characterized in that, The first sliding hole and the Kirschner wire are clearance fit.

9. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 7, characterized in that, The inner end of the reinforcing shaft is fixed to the Kirschner wire sliding seat, and the outer end is slidably engaged with the second sliding hole provided on the Kirschner wire fixing seat. The Kirschner wire fixing seat is also provided with a reinforcing shaft fixing mechanism.

10. The variable stiffness external fixation device for accelerating lower limb fracture healing as described in claim 9, characterized in that, The reinforcing shaft fixing mechanism includes a fastening screw hole that is directly opposite the second sliding through hole, and a fastening bolt is screwed into the fastening screw hole; The radial stiffness of the Kirschner wire ranges from 150 N / mm to 1200 N / mm.

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