TWI730883B - Kinematic axis target device for knee arthroplasty - Google Patents

Abstract

A kinematic axis target device for knee arthroplasty includes two arms and a connection member. The two arms are placed between the proximal tibial and the distal femur that are held by a ligament, such that the medial condyle and lateral condyle of the femur clamp the two arms on the tibial plateau with corresponding curvatures. The connection member naturally positions a reference axis according to the positions on which the two arms are located when being clamped. The reference axis is made to be approximately parallel to the kinematic axis of the pivotion between the medial condyle and lateral condyle of the femur on the tibial plateau. Thus, the joint surface between the proximal tibial and the distal femur is trimmed according to the reference axis.

Description

Motion axis positioner for artificial knee replacement

The present invention relates to an instrument for artificial knee joint replacement, in particular to a motion axis positioner for artificial knee joint replacement.

There are many joints in the human bones. The knee joints of the lower limbs bear heavy weight and frequent friction. Therefore, the knee joints will inevitably cause wear after years of use. At this time, pain will follow, and when the wear is severe, it will cause People with inconvenience and life troubles must be improved by surgical replacement of artificial joints.

At present, the current total knee arthroplasty (Total Knee Arthroplasty, TKA) involves first trimming the proximal tibial (Proximal Tibial) and distal femur (Distal Femur), and then implanting artificial joints and cushions. . Among them, because the proximal tibia and distal femur cannot be restored after surgical resection, in order to make the artificial joint fit the patient’s original bone and have good adaptability after the operation, how to treat the proximal tibia and the distal femur in a correct way Renovation of the distal femur is one of the important topics of knee replacement surgery.

Regarding the trimming of the proximal tibia and the distal femur, a known method is the so-called mechanical alignment (Mechanical Alignment, MA). The so-called mechanical axis system connects the center of rotation of the femoral head through the center of the proximal tibia to the midpoint of the medial and lateral malleolus. The line is used as a reference axis, which can generally be obtained through X-ray fluoroscopy. The proximal tibia and the distal femur can be cut out of the mechanical axis to cut out the vertical articular surface, and then the artificial joint and cushion body are implanted to complete the artificial joint replacement. However, it has been found in clinical practice that less than 2% of the lower extremities conform to the mechanical axis setting if compared with the proportion of the census. Many patients often have the so-called "unequal degree of knee varus" or "knee valgus" deformity. When the patient’s original proximal tibia and distal femur articular surfaces are not perpendicular to the mechanical axis, if the above-mentioned mechanical axis calibration is performed to obtain a vertical mechanical axis articular surface for artificial joint replacement, although the articular surface after the operation It can be restored to be perpendicular to the mechanical axis, but the collateral ligament on the narrow side before correction must be stretched during the operation to correct the deformity of the so-called "knee varus" or "knee valgus", but the collateral ligament is stretched Open and cause slack, and cause knee joint instability and cause walking weakness and pain sequelae.

Another known way to trim the proximal tibia and the distal femur is the so-called Kinematic Alignment (KA). The so-called Medial/Lateral condyle femur (Medial/Lateral condyle femur) is relative to the lower limb when it is bent. Tibial Plateau (Tibial Plateau) reference axis for turning. The difference from the aforementioned mechanical axis calibration knee replacement surgery is that if the knee replacement surgery is performed according to the movement axis calibration, the articular surface of the proximal tibia and distal femur will almost overlap with the articular surface before trimming after correction. The original angle between the tibia and the femur is still maintained after the operation, and the collateral ligaments on both sides of the knee joint do not need to be stretched during the operation. Therefore, compared to the knee replacement surgery with mechanical axis calibration, the collateral ligaments will not be loosened. The sequelae of knee joint walking weakness and pain.

The "axis of motion" is a virtual imaginary axis and not measurable by the naked eye. A known way to find the axis of motion is to measure the upper and lower positions of the patient's femur and tibia through images, and through the dynamic process of lower limb swings. After calculation and modeling, create a personalized surgical tool (Personal Specific Instrument, PSI), and finally apply the personalized surgical tool for knee replacement surgery with the axis of motion aligned. However, if you want to obtain the personalized surgical tools for knee replacement surgery, the current practice is to perform image measurement and computational modeling, and then send the modeling-related data to Singapore for certification. It was produced by the mold factory in Belgium. The certification and production process took two weeks to one month to complete, and the production cost was expensive, resulting in time-consuming, labor-intensive and cost-intensive knee replacement surgery using movement axis alignment. high.

Another example is the United States Announcement No. US08900242B2 Invention Patent, which is a Stylus Assembly, which mainly uses one end (17, 18) to abut the unworn posterior femoral condyle (56) to provide a reference surface for positioning. The reference surface is used to perform the excision of the proximal tibia, and the needle and pen assembly of the invention patent is still designed with a tool based on the principle of mechanical axis alignment. This case uses a plurality of needle and pen components, and the end of each needle and pen component has different thickness (such as 1~3mm) design, in order to correspond to the different articular surface wear and tear due to the loosening of the medial collateral ligament, which is used to prop up the knee joint. The condyle bone to restore the medial collateral ligament to normal tightness is not actually used to locate the axis of motion; and in clinical practice, it has been found that if the aforementioned end abuts against the lateral femoral condyle on the unworn side, it provides Resection of the proximal tibia on the reference surface of the positioning will easily lead to insufficient resection of the worn tibial medial condyle; on the contrary, if the aforesaid end abuts against the worn side femoral medial condyle, it will easily lead to unworn external tibial condyles. There are too many condylar resections, so it must be repeatedly corrected during the resection process to achieve balance, which causes inconvenience and troubles in the repair of the knee joint surface.

In order to solve the above-mentioned problems, the present invention provides a motion axis positioner for artificial knee arthroplasty to assist the surgeon in positioning the motion axis before repairing the articular surfaces of the proximal tibia and the distal femur.

An embodiment of the present invention provides a motion axis locator for artificial knee joint replacement, which includes two spoon arms and a connecting body. The two spoon arms of the guiding cutting member are symmetrically arranged on the same side of the guiding cutting member connecting body. And the two spoon arms of the guiding cutting piece are respectively curved to correspond to the curvature of the human femoral medial and lateral condyles on the sagittal sphere. The two spoon arms of the guiding cutting piece can be inserted into the proximal tibia and the distal femur along the sagittal axis. The proximal tibia and the distal femur are restrained by the ligaments, so that the medial condyle and the lateral condyle are respectively clamped against the guiding and cutting piece with corresponding curvatures and the two spoon arms are placed on the tibial platform, and the guiding and cutting piece connecting body is cut according to the guiding The position of the second spoon arm when it is clamped naturally locates a reference axis, and the reference axis of the guiding cutting member is approximately parallel to the movement axis of the medial and lateral condyles relative to the tibial platform. The reference axis is used to trim the articular surface between the proximal tibia and the distal femur.

Thereby, the motion axis positioner for artificial knee replacement of the present invention is a surgical aid with simple structure and easy operation. Before the articular surface of the proximal tibia and the distal femur is repaired, its positioning can be compared with the motion axis. With reference to the axis, the articular surface of the proximal tibia and distal femur can be repaired, and clinical experiments have proved that the results of the articular surface of the proximal tibia and distal femur using personalized surgical tools are the same as accurate, and the operation is simple Easy to implement, in order to achieve the effect of saving the time and money spent on calculation model verification and mold opening.

In order to facilitate the description of the central idea of the present invention expressed in the column of the above-mentioned summary of the invention, specific embodiments are used to express it. The various objects in the embodiment are drawn according to the proportion, size, deformation or displacement suitable for explanation, rather than drawn according to the proportion of the actual element, which will be described first.

Please refer to FIG. 1 to FIG. 8. The present invention provides a motion axis positioner 100 for artificial knee joint replacement surgery. As the name suggests, it is used for positioning the motion axis during artificial knee joint replacement surgery. The definition of the motion axis has been described in the prior art. It is clearly described and will not be repeated here. The moving axis positioner 100 mainly includes two spoon arms 10 and 20 and a connecting body 30, and in a preferred embodiment, it further includes a guide cutting member 40, wherein:

The two spoon arms 10, 20 are symmetrical in shape and are respectively curved and similar to the shape of a spoon. The curved arcs of the two spoon arms 10, 20 correspond to the inner and outer condyles of the femur on the sagittal sphere. Curvature. In this embodiment, each of the spoon arms 10, 20 is flat and has a smooth surface, and each of the spoon arms 10, 20 has side walls 11, 21 on both sides of the middle part, respectively, and the two side walls 11 of the spoon arm 10 are It is arranged symmetrically, the side walls 21 of the spoon arm 20 are also arranged symmetrically, and the top edges of the side walls 11 and 21 are flat. The connecting body 30 is provided with two spoon arms 10 and 20 on the same side. In this embodiment, the connecting body 30 is elongated and extends along a straight line, and forms a long rectangular block. The connecting body 30 is in the width direction. The two sides are respectively flat along the extending direction of the straight line.

The spoon arm 10 is a fixed spoon arm in this embodiment, and the other spoon arm 20 is a movable spoon arm in this embodiment. The spoon arm 10 is integrally formed at one end of the connecting body 30; the spoon arm 20 is provided with After the connecting body 30 can slide along the length of the connecting body 30 to adjust the distance between the spoon arm 20 and the spoon arm 10, the spoon arm 20 can be fixed to the connecting body 30. Preferably, the spoon arm 20 has an end 22, and the end 22 has a sliding groove 23 therein. The inner contour of the sliding groove 23 corresponds to the cross-sectional contour of the connecting body 30, and the end 22 of the spoon arm 20 is provided with the sliding groove 23. The connecting body 30 is sleeved so that the spoon arm 20 can slide along the length of the connecting body 30. The radius of curvature R of the scoop arm 20 in a curved arc is 17mm to 29mm, which is suitable for the different curvatures of the medial and lateral femoral condyles on the sagittal sphere, and it naturally reflects when the knee joint performs straight-bending motions The motion axes of the medial and lateral femoral condyles are different when they rotate like a sphere, and the radius of curvature R of the two spoon arms 20 in this embodiment are both 25 mm. In addition, the second scoop arm 20 of this embodiment corresponds to the curvature of the sagittal sphere of the medial and lateral femoral condyles, and the thickness t is 1 mm.

In conclusion, the connecting body 30 of this embodiment has a guide groove 31 on the side different from the two spoon arms 10 and 20. The guide groove 31 is also opened along the length direction of the connecting body 30, that is, the guide groove 31 penetrates and connects At both ends of the body 30, the end 22 of the spoon arm 20 has a convex portion 24 in the sliding groove 23. The convex portion 24 is provided corresponding to the guide groove 31; the end 22 is provided on the side different from the convex portion 24. There is a tightening piece 25. When the end portion 22 is sleeved on the connecting body 30 with a sliding groove 23 and the convex portion 24 is located in the guide groove 31, the operator can actuate the tightening piece 25 to press the tightening piece 25 and The convex portion 24 in the guide groove 31 is clamped by the connecting body 30 to be positioned. The end portion 22 has a convex portion 24 to cooperate with the guide groove 31 of the connecting body 30, which is only an embodiment of the present invention. In different embodiments, the convex portion 24 may also be provided on the connecting body 30. The guide groove 31 can be provided at the end 22, and can also achieve a limiting effect when the end 22 slides on the connecting body 30.

Preferably, the pressing member 25 is a bolt in this embodiment, and the end portion 22 is provided with a screw hole 221 corresponding to the pressing member 25, and the pressing member 25 is screwed in the screw hole 221 so as to be screwed against the connecting body. 30. When the tightening member 25 is screwed to a certain depth in the screw hole 221, the tightening member 25 is linked to the convex portion 24 so that the end portion 22 is clamped on the connecting body 30 to fix the spoon arm 20 on the connecting body 30 fixed. In addition, the present embodiment has a handle 32 on the connecting body 30. The handle 32 extends perpendicular to the linear extension direction of the connecting body 30 (that is, the handle 32 and the connecting body 30 are connected in a T shape), and the handle 32 Contrary to the direction in which the two spoon arms 10, 20 extend from the connecting body 30, the handle 32 of this embodiment extends from one side of the connecting body 30 with the guide groove 31, and the handle 32 is located in the second spoon arm 10, Between 20, this handle 32 can only be held by the operator.

In the actual operation of the motion axis positioner 100 of the above embodiment, taking the left foot as an example, the patient cuts the skin and flesh tissue at the knee joint, and when the joints of the proximal tibia T and the distal femur F are visible, place two spoons The arms 10 and 20 are placed between the proximal tibia T and the distal femur F along the sagittal axis Y (as shown in Figure 4). At this time, the proximal tibia T and the distal femur F are affected by ligaments L (including lateral collaterals). Ligament and cruciate ligament), the proximal tibia T and the distal femur F will maintain an opposite tension, and the two spoon arms 10 and 20 can maintain contact between the tibial plateau P and the femoral medial condyle IC and lateral condyle OC. And the medial condyle IC and lateral condyle OC are clamped against the two spoon arms 10, 20 on the tibial platform P (as shown in FIG. 5) with corresponding curvatures, and as the two spoon arms 10, 20 are parallel or in the horizontal direction There is a height difference. At this time, the connecting body 30 will naturally locate a reference axis X according to the position of the two spoon arms 10 and 20 when they are clamped. This reference axis X pivots with the medial condyle IC and lateral condyle OC on the tibial plateau P The rotation axis K (please refer to Figure 8) is nearly parallel. At this time, the articular surface between the proximal tibia T and the distal femur F can be trimmed according to the reference axis X.

In order to cooperate with the motion axis positioner 100 of the above embodiment to implement artificial knee replacement, after the reference axis X is positioned on the above-mentioned connecting body 30, the present invention further includes a guide cutting member 40 in a preferred embodiment to assist the tibia Renovation of platform P. The guiding cutting member 40 has a sleeve opening 41 and a fixing portion 42. The sleeve opening 41 is positioned opposite to the guiding cutting member 40, and the fixing portion 42 is located at the position of the guiding cutting member 40. It is opposite to the bottom, and the guiding cutting member 40 has a long slit 43 between the sleeve opening 41 and the fixing portion 42.

Preferably, the guiding and cutting member 40 has a mounting groove 44 between the sleeve opening 41 and the fixing portion 42. The mounting groove 44 is open on one side of the guiding and cutting member 40, and the guiding and cutting member 40 has a piece of The body 45 has a long slit 43, the block 45 is assembled in the installation groove 44 from the open side of the installation groove 44, and the block 45 can be positioned in the installation groove 44.

In addition, the fixing portion 42 has a plurality of perforations 421, and each of the perforations 421 can be used for piercing the bone screws 50 for surgery, so as to lock the fixing portion 42 in the proper position of the proximal tibia T. Furthermore, the long slit 43 on the block 45 is inclined from high to low from the side with the handle 32 of the connecting body 30 to the side with the two spoon arms 10 and 20 (as shown in Fig. 3), And because the block 45 can be separated and assembled from the guide cutting member 40, the long slit 43 of the block 45 can be designed with different inclination, and the block 45 of the long slit 43 with different inclination can be selected according to the actual situation. Assembled in the guide cutting member 40, the artificial joint replacement is performed smoothly.

Continuing the actual operation of the aforementioned moving axis positioner 100, when the connecting body 30 has naturally positioned the reference axis X according to the position where the two spoon arms 10 and 20 are clamped, the handle 32 corresponds to the position of the connecting body 30 When extending out, the sleeve 41 of the guiding cutting member 40 can be sleeved with the corresponding thickness of the handle 32 (as shown in FIG. 6), and the guiding cutting member 40 can be moved along the handle 32. Lean to the proximal tibia T, and then use the bone screw 50 to select a suitable perforation 421 to pass through and lock it on the proximal tibia T (as shown in Figure 7), and the fixed portion 42 of the guide cutting member 40 can be positioned at the position Fixed on the proximal tibia T, the long slit 43 on the block 45 is parallel to the reference axis X in the length direction, so that a cutting tool (not shown) can extend into the long slit 43 along the reference axis X and resection of the tibial plateau P can complete the articular surface modification between the proximal tibia T and the distal femur F. At this time, after the proximal tibia T is amended to remove the tibial plateau, the movement axis K (ie reference axis X) can be obtained Parallel section.

From the above description, it is not difficult to find that the characteristic of the present invention is that the motion axis positioner 100 for artificial knee replacement surgery of the present invention can be composed of only two spoon arms 10, 20 and a connecting body 30, which is actually a simple structure and operation A simple surgical aid. Before the articular surfaces of the proximal tibia and distal femur are trimmed, the medial condyle IC and lateral condyle OC can be used to clamp the two spoon arms 10 and 20 on the tibial plateau P with corresponding curvatures. Locate a reference axis X that is compared to the axis of motion, then the articular surface of the proximal tibia T and the distal femur F can be successively repaired, and it has been confirmed by clinical experiments that the use of personalized surgical tools for the proximal tibia as described in the previous technology The results are as accurate as the articular surface modification of the distal femur, and there will be no problems that must be repeatedly corrected during the resection process to achieve balance. Even if you are not an experienced surgeon, you can simply locate it with the motion axis positioner 100 of the present invention The comparison of the reference axis X of the motion axis, thereby achieving the effect of saving the time and money spent in the verification of the calculation model and the opening of the mold.

The above-mentioned embodiments are only used to illustrate the present invention, and are not used to limit the scope of the present invention. All modifications or changes made without violating the spirit of the present invention fall within the scope of the present invention's intended protection.

100: Motion axis locator 10: Spoon arm 11: side wall 20: spoon arm 21: side wall 22: end 221: screw hole 23: chute 24: Convex part 25: Compression piece 30: Connecting body 31: Guide groove 32: handle 40: guide cutting piece 41: Sleeve 42: Fixed part 421: Perforation 43: Long slit 44: installation slot 45: block 50: bone screw K: motion axis F: Distal femur IC: medial condyle L: Ligament OC: Lateral condyle P: Tibial plateau T: Proximal tibia X: Reference axis Y: Sagittal axis R: radius of curvature t: thickness

Fig. 1 is a three-dimensional assembly diagram of a moving shaft positioner according to an embodiment of the present invention. Fig. 2 is an exploded configuration diagram of the moving shaft positioner of the embodiment of the present invention. Fig. 3 is a side cross-sectional view of Fig. 1 as seen from section line 3-3. Fig. 4 is a schematic side view of the movement axis positioner of the embodiment of the present invention inserted into the knee joint with two spoon arms along the sagittal axis. Fig. 5 is a schematic view of the movement axis positioner of the embodiment of the present invention before being inserted into the knee joint along the sagittal axis with two spoon arms. Fig. 6 is a schematic front view of Fig. 5 after the guide cutting member is installed on the handle. Fig. 7 is a schematic diagram of the guide cutting member of Fig. 6 fixed to the proximal tibia with bone screws. Figure 8 is a schematic diagram of the modified tibial plateau of the proximal tibia. In the figure, it can be seen that the tibial plateau is parallel to the axis of motion after the resection.

100: Motion axis locator

10: spoon arm

11: side wall

20: spoon arm

21: side wall

22: end

221: screw hole

25: Compression

30: Concatenation

31: guide groove

32: handle

40: Guide cutting pieces

41: Sleeve

42: fixed part

421: Piercing

43: Long slit

45: Block

Claims (9)

A motion axis positioner for artificial knee joint replacement surgery, which includes two spoon arms and a connecting body. The two spoon arms are arranged on the same side of the connecting body, and the two spoon arms are symmetrical in shape and are respectively curved and arc-shaped to correspond The curvature of the human femoral medial and lateral condyles on the sagittal sphere, the two spoon arms can be placed between the proximal tibia and the distal femur along the sagittal axis, and the proximal tibia and the distal femur are restrained by the ligaments, so that the inner The condyle and the lateral condyle are respectively clamped against the two scoop arms on the tibial platform with corresponding curvatures, and the connecting body naturally locates a reference axis according to the position when the two scoop arms are clamped, and the reference axis is connected to the medial and lateral condyles. The motion axis of the condyle relative to the tibial plateau is approximately parallel, and the articular surface between the proximal tibia and the distal femur is trimmed according to the reference axis; wherein, the connecting system is elongated and extends along a straight line, and the two spoon arms include a A fixed spoon arm and a movable spoon arm are integrally formed at one end of the connecting body; the movable spoon arm is arranged on the connecting body and can slide along the length of the connecting body to adjust the movable spoon arm and the connecting body. The distance between the spoon arms is fixed and then fixed to the connecting body. The movement axis locator for artificial knee replacement surgery according to claim 1, wherein the movable spoon arm has one end portion, the end portion has a chute, and the inner contour of the chute corresponds to the cross-sectional contour of the connecting body , The end part is sleeved with the connecting body by the sliding groove so as to be slidable along the length direction. The motion axis positioner for artificial knee replacement surgery according to claim 2, wherein the connecting body has a guide groove on a side different from the two spoon arms, and the guide groove is opened along the length direction of the connecting body, and The end has a convex part corresponding to the guide groove in the chute, and the end part is provided with a pressing piece on the side different from the convex part, and the end part is sleeved in the chute When the connecting body and the convex part are in the guide groove, the pressing member is actuated to clamp the connecting body with the convex part for positioning. The motion axis positioner for artificial knee joint replacement surgery according to claim 3, wherein the urging member is a bolt, the end portion is provided with a screw hole corresponding to the urging member, and the urging member is screwed on the screw In the hole, it can be screwed to abut on the connecting body to clamp the end part on the connecting body with the convex part. The motion axis positioner for artificial knee replacement surgery according to claim 2, wherein the connecting body has a handle, and the handle extends perpendicularly with respect to the linear extension direction of the connecting body, and the handle and the The two scoop arms extend from the connecting body in opposite directions, and the handle is located between the two scoop arms; each of the scoop arms has a curved arc with a radius of curvature of 17mm to 29mm. The motion axis positioner for artificial knee joint replacement as claimed in claim 5, further comprising a guide cutting member having an upper cuff and a lower fixing part, and the guide The lead-cutting member has a long slit between the sleeve opening and the fixing portion. When the connecting body is naturally positioned on the reference shaft as described above, the handle is sleeved on the sleeve opening with a corresponding thickness, and the fixing is The part is fixed to the proximal tibia at the position, and the long slit is parallel to the reference axis in the length direction, so that the cutting tool can extend into the long slit and trim the tibial platform along the reference axis. The motion axis positioner for artificial knee arthroplasty according to claim 6, wherein the guide cutting member has a mounting groove between the sleeve and the fixing portion, and the mounting groove is in the guide cutting member One side is open, the guide cutting member has the long slit in one piece, and the block is assembled and positioned in the installation groove from the open side of the installation groove. The motion axis positioner for artificial knee replacement surgery according to claim 7, wherein the long slit is in the width direction of the block, and the two spoon arms are located on the side with the handle relative to the connecting body One side slopes from high to low. The motion axis positioner for artificial knee replacement surgery according to claim 6, wherein the fixing part has a plurality of perforations, and the bone screw used for surgery can choose one of the perforations to pass through, and lock the fixing part in The proper position of the proximal tibia.

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