RU2187975C1 - Method for setting knee joint prostheses - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves bending knee joint by 90 deg and forming canal in bone along the anatomical axis of the femur. Intramedullary nail is introduced into the canal and valgus angle relative to the nail axis is formed by using valgus angle guide device with its following adjustment. Then, osteotomy guide device is set to determine femur condyles resection level. Distal femur osteotomy is carried out in the plane set in perpendicular to the valgus angle direction corresponding to the determined level. Measurement template with openings is applied to and fixed on the sawn surface of the femur to determine endoprosthesis femur part size. Two canals are formed in the femur through the template openings for fixing a resection template or the femur part. Then the resection template is fixed by means of these canals on the distal sawn surface, anteroposterior femur portions resection is performed and angular resections of the sawn surfaces are done to make their control examination later on. Characteristic features are related to setting tibial part manufactured as metal platform with a hole and pedicle and polyethylene endoprosthesis platform mountable between the femoral and tibial parts. When making intermediate resection of the proximal part, the crus is positioned at an angle of 90 deg to the table surface and fixed in the position protruding forward. The intermediate resection is carried out at a depth set in correspondence to the condyle that is destroyed most of all in the plane set in perpendicular to the anterior crus surface. The so produced saw cut surface is adjusted in extended knee joint state by setting femoral part metal TEST-prosthesis on the saw cut surface between which and tibial saw cut surface one of the polyethylene templates is placed. Polyethylene template height is selected by measuring the degree of lateral ligament tension. The height is defined as sum of tibial part metal platform height and polyethylene endoprosthesis platform height and corresponds to one of the sizes in the range of 9.5-17.5 mm. Final tibia resection is carried out on the basis of adjustment results. Then tibial part sizes are selected by means of template with an opening on the cortical surface under condition of the external template surface fully covering cortical surface of the produced saw cut. The template is to be fixed on the saw cut surface, the crus is moved forward and bed is formed in the tibia through the opening for the pedicle to be placed there. Flexion and extension in the knee joint and final level of ligaments tension are tested by applying metal TEST-prostheses of femoral and tibial parts. Then the corresponding endoprosthesis parts are fixed on the femoral and tibial saw cuts. EFFECT: enhanced physiological match to living knee joint properties. 13 dwg

Description

 The invention relates to surgery and can be used for operations on the complete replacement of the knee joint.

 There is a method of installing a knee endoprosthesis, which consists in installing a template for resection in contact with the condyles of the femur with the possibility of adjusting the position of the osteotomy plane passing through the distal femur, in determining the size of the femoral component with the subsequent formation of channels under the femoral component and resection of the anterior and the back of the femur and angular resections of the sawdust (see US Pat. PCT 97/30648).

 This method is not flexible and accurate enough and is designed only for highly qualified surgeons and therefore has limited use.

The closest analogue is the knee joint endoprosthetics method, which means that the knee joint is inflected at an angle of 90 ^° , then a channel is formed in the femur along the anatomical axis, an intramedullary nail is inserted into it, relative to its axis, they form and adjust the direction of the mechanical axis, after which the resection guide determines the level of resection, according to which through the distal section perpendicular to the direction of the mechanical axis the femur is resected, the measurement template is fixed on the resulting fillet with the holes that determine the size of the femoral component of the endoprosthesis, with the subsequent formation of two channels in the femur through the holes in the template for attaching the template for the resection or the femoral component, and then this template is performed according to the received measurements of resections of the anteroposterior femur, angular resections of their filings, after which they are monitored (see US Pat. US 5562675,1996).

 However, in the given analogs, the question of a coordinated selection of the parameters of the tibial and femoral components close to physiological has not been resolved. A coordinated sequence of actions taken during the installation of the femoral and tibial components and the platform located between them has not been selected. In addition, the issues of selecting the parameters of the tibial component and platform according to the degree of tension of the lateral ligaments are not resolved. This leads to instability of the knee joint with an established endoprosthesis and to biomechanical disturbances during movement.

 The objective of the proposed technical solution is to increase the physiological adequacy of the living knee joint and ensure the stability of the knee joint with an established endoprosthesis.

To solve the problem in the proposed method of knee replacement, which consists in the fact that the knee joint is inflected at an angle of 90 ^o , then a channel is formed in the femur along the anatomical axis, a nail is inserted into it, directed intramedullary, relative to the axis of which with a mechanical axis guide form and adjust the direction of the mechanical axis, after which the resection guide determines the level of resection, in accordance with which through the distal section perpendicular to the direction of the fur on the axis of the axis, the femur is resected, on the resulting filament, a measuring template is fixed with holes that determine the dimensions of the femoral component of the endoprosthesis, with the subsequent formation in the femur through the holes in the template of two channels for attaching the template for resection or the femoral component, and then performing this template on obtained measurements of resections of the anteroposterior femur and angular resections of their filings, after which control of these filings is carried out, according to the invention the tibial component is installed in the form of a metal platform with an opening and a leg and located between the femoral and tibial components of the polyethylene endoprosthesis platform, preliminary resection of the tibia is performed in the position advanced anteriorly through the proximal section, perpendicular to the anterior surface of the lower leg along the depth of the most destroyed condyle, after which the unbent state of the knee joint carry out the correction of the received sawdust of the tibia, which they are removed by installing a metal TEST prosthesis of the femoral component between the thigh and the sawdust of the tibia, one of the polyethylene templates is installed and moved, and the height of the lateral ligaments is adjusted to the height of the polyethylene template, which is equal to the sum of the heights of the metal platform of the tibial component and the plastic platform of the endoprosthesis and corresponds to one of the sizes of the range 9.5-17.5 mm, according to the results of the adjustment, the final resection of the tibia is carried out, after which using the template with the hole, the end dimensions of the tibial component are selected with the condition that the outer surface of the template with the hole is completely located on the cortical surface of the resulting sawdust, after which this template is fixed on the sawdust, the tibia is advanced anteriorly and a bed under the leg is formed through the hole in the template, then, with the help of metal TEST prostheses of the tibial and femoral components mounted on the corresponding sawdust, the sphi check is performed according to the degree of tension of the lateral ligaments anija and knee extension, followed by installation and fixing of the respective components on sawdust.

 The technical result achieved in this case is that the stability of the knee joint with an installed endoprosthesis is ensured.

 Figure 1 shows the formation of the canal in the femur along the anatomical axis and the introduction of a nail directed intramedullary into it.

 Figure 2 shows the correction of the direction of the mechanical axis.

 In FIG. 3 shows a resection through the distal femur.

 Figure 4 shows the determination of the size of the femoral component.

 Figure 5 shows the drilling of two holes in the femur.

 Figure 6 shows the implementation of the sawdust of the femur with a template for resection.

 7 shows a knee joint with an installed endoprosthesis.

 On Fig shows a preliminary resection through the proximal tibia.

 Figure 9 shows the adjustment of the sawdust of the tibia according to the degree of tension of the lateral ligaments.

 Figure 10 shows the final resection.

 In FIG. 11 shows the formation in the tibia of a bed under the leg of the tibial component.

 On Fig, 13 shows a check of flexion and extension of the knee joint.

Figure 1-13 shows the following positions:
1 - femur;
1 '- sawdust passing through the distal femur;
2 - tibia;
2 '- sawdust of the tibia;
2 '' - anterior surface of the tibia;
3 - channel;
3 '- a nail;
4 - direction of the anatomical axis;
5 - a guide;
5 'is the direction of the mechanical axis;
6 - resection guide;
7 - plane of resection,
8 - measuring template;
8 '- holes;
9 - channels;
10 - a template for resection;
11 - tibial component;
11 '- a metal platform;
11 '' - hole in a metal platform;
12 - leg;
13 - femoral component;
14 - a polyethylene platform;
15 - plane of resection of the tibia;
16 - lateral ligaments;
17 - template;
17 '- holes;
18 - metal TEST prosthesis of the femoral component;
19 - metal TEST prosthesis of the tibial component;
20 - a polyethylene template;
21 - a bed under the leg.

 The method is as follows.

 In the proposed method, in the process of total knee replacement, a device is installed to completely replace the knee joint according to US Pat. RU 2145821 from 02.27.2000, including the femoral, tibial components 13, 11 and the polyethylene platform 14 located between them.

The knee joint is brought into flexion at an angle of 90 ^° , then a channel 3 is formed in the femur 1 directed intramedullary (see Fig. 1) along the anatomical axis 4. A nail 3 'is inserted into the formed channel 3, with respect to the direction of which the guide 5 forms a mechanical direction axis 5 '. The mechanical axis makes an angle with the anatomical axis, the value of which is set before the operation. Correcting the correct choice of the given angle is carried out by checking the intersection of the mechanical axis of the center of the femoral head (see figure 2). Next, perpendicular to the mechanical axis 5 'along the plane of the resection 7, passing through the distal femur, a resection of the femur is performed. The level of resection is determined by the resection guide 6 (see Fig. 3).

 On the resulting sawdust 1 'impose and fix the measuring template 8, which is made with holes 8'. Using the measuring template 8 determine the size of the femoral component. After that, through the holes 8 'in the measuring template 8, two channels 9 are drilled (see Figs. 4, 5), which are intended for the final fastening of the femoral component 13, and at the moment these channels 9 are used for fastening the template for resection 10. Using the latter according to the received measurements perform a resection of the anteroposterior part of the femur, then perform angular resections of the received filings (see Fig.6). The control of the completed filings is carried out with a metal TEST prosthesis 18.

 The sawdust 1 'of the femur 1, made perpendicular to the mechanical axis, is used as the base for the subsequent steps of the method associated with the installation of the tibial component. As already mentioned above, in the proposed method, a device is installed to completely replace the knee joint, which contains not only the femoral component 13, but also the tibial component 11, made in the form of a metal platform 11 'with an opening 11' 'and a leg 12 and located between femoral 13 and tibial 11 components of the plastic platform 14.

When conducting a preliminary resection, the tibia 2 is placed at an angle of 90 ^o to the table surface and is fixed in the forward position (see Fig. 8). A preliminary resection is performed through the proximal section along the depth of the most destroyed condyle along the plane of the tibial resection 15, which is perpendicular to the anterior surface of the tibia 2 ''.

 After that, according to the degree of tension of the lateral ligaments 16, the resulting sawdust 2 'is adjusted. Correction is performed in the unbent state of the knee joint.

 A metal TEST prosthesis 18 of the femoral component 13 is installed on the sawdust 1 ′ of the femur 1, between which one of the polyethylene templates 20 is mounted and moved between the sawdust 2 ′ of the tibia 2 (see Fig. 9). In the case of a lower height of the polyethylene template than is required, there is a play in the movable joint and rocking of the tibia in the frontal plane. A higher polyethylene pattern cannot be installed due to excessive tension on the lateral ligaments. Properly selected height of the polyethylene template allows to obtain a backlash-free connection of the moving parts of the endoprosthesis and to achieve lateral stability of the knee joint. This height is the criterion for assessing the optimal tension of the lateral ligaments and it is equal to the sum of the height of the metal platform 11 'of the tibial component 11 and the height of the polyethylene platform 14. The proposed method is designed to install the endoprosthesis according to US Pat. 2145821, which is made in compliance with biomechanics, and all movements of the knee joint with an installed endoprosthesis have stable readings if the height of its polyethylene template is equal to one of the sizes in the range 9.5-17.5. This ensures the stability of the knee joint with an established endoprosthesis.

 According to the results of the adjustment, taking into account the selected height of the polyethylene template 20, the final resection of the tibia 2 is performed (see Fig. 10).

 The selection of the sizes of the tibial component 11 is performed using the template 17 with the hole 17 'with the condition that the outer surface of the template 17 is completely located on the cortical surface of the resulting sawdust.

 After that, the template 17 with the hole 17 'is fixed on the surface of the sawdust, the tibia is advanced anteriorly and formed in it through the hole 17' in the template 17, the bed 21 under the leg 12 of the tibial component (see Fig. 11).

 Then, using metal TEST prostheses, respectively, of the tibial and femoral components 19, 18, mounted on the corresponding sawdust 2 ', 1', check the flexion and extension of the knee joint by tensioning the lateral ligaments 16 (see Fig. 12, 13).

 After that, the corresponding components of the endoprosthesis are installed and fixed on the obtained sawdust.

 Example 1

 Patient K, 48 years old.

 Diagnosis: deforming arthrosis of the left knee joint.

 The disease is a result of rheumatoid arthritis.

Before the operation, the direction of the mechanical axis of the femur of the left knee joint was determined, according to which the angle between the mechanical and anatomical axes of the femur is approximately 7 ^o .

 The position of the patient on the operating table on the back. A hemostatic tourniquet is applied to the upper third of the femur of the left knee joint. It is advisable to administer an antibiotic intravenously.

 After opening the cavity of the knee joint, the surgeon assesses the state of internal structures (condyles, synovial membrane, ligaments, cartilage tissue). Assesses the tension of the lateral ligaments and the degree of instability of the knee joint.

After that, the knee joint was transferred into flexion at an angle of 90 ^o .

 The formation of the channel is carried out along the anatomical axis of the femur with a drill with a diameter of 8 mm to a depth of 4-5 cm, followed by indentation of the drill along the entire length.

A nail directed intramedullary is introduced into the formed channel, with respect to the axis of which a direction of the mechanical axis is formed corresponding to the left knee joint, making an angle equal to 7 ^o with the anatomical axis.

After that, the correction of this angle is 7 ^o . When checking confirmed the intersection of the direction of the mechanical axis of the center of the femoral head and the correct choice of the angle of 7 ^o . After that, a resection guide is placed on the femur and the level of resection of the femur extending along a plane located proximal to the femoral condyles by 9 mm is determined. In accordance with this level, the femur is resected perpendicularly to the corrected direction of the mechanical axis along the plane crossing the distal section. The quality of the resulting sawdust is good, since when checking with glass, the complete adhesion of the surface of the sawdust to the glass was found. The resection level is sufficient.

 The dimensions of the femoral component are determined by a measuring template, which is fixed on the plane of the resulting sawdust.

 After that, a drill with a diameter of 5 mm with a stop through the holes in the measuring template is drilled two channels in the femur for fastening the resection template or endoprosthesis. On the resulting sawdust, a resection template is fixed and, according to the measurements obtained, a resection of the front and back parts of the femur and an angular resection of the sawdust are performed.

 As a result of the control of the performed filings of the femur, which is performed with a metal TEST prosthesis of the femoral component, it was established that the resection was carried out correctly. After that, the metal TEST-prosthesis is removed using a sliding hammer and a hook in the form of a plate.

When conducting preliminary resection of the proximal tibia, the tibia is positioned at an angle of 90 ^o to the table surface and is fixed in the forward position extended.

 Then, the level of preliminary resection is determined by the depth of the most destroyed tibial condyle and the resection is performed with a saw along a plane perpendicular to the axis of the tibia.

 After that, the resulting sawdust is adjusted by tensioning the lateral ligaments. For this, in an unbent state of the knee joint, a metal TEST prosthesis of the femoral component is installed on the distal sawdust of the femur, between which and a tibial sawdust, a polyethylene template with a height of 9.5 cm is first installed. In this case, the polyethylene template is moved between the metal TEST prosthesis of the femoral component and sawdust of the tibia, as a result of which a weak tension of the lateral ligaments was determined. When a polyethylene template 11.5 cm high was installed on the thigh sawdust, insufficient tension of the lateral ligaments was established. When installing a polyethylene template 12.5 cm high on the thigh bone, they came to the conclusion that the tension of the lateral ligaments corresponds to the physiological norm. This height is chosen as the basis and is equal to the sum of the heights of the metal platform of the tibial component and the polyethylene platform of the endoprosthesis. According to the results of the adjustment, a final resection of the tibia was performed.

 The size of the tibial component was selected using a template with a hole mounted on the tibia sawdust with the condition that the outer surface of the template was completely located on the cortical surface of the resulting sawdust.

 A sized template was fixed on the surface of the tibia sawdust with two mounting peaks. The tibia tibia was advanced anteriorly and a small sleeve was first installed in the hole of the template under the drill with a diameter of 10 mm and a hole was drilled through the small sleeve with a drill in the tibia. After removing the small sleeve, a larger sleeve is installed in its place to form a bed under the protrusion on the leg of the tibial component. The final refinement of the bed was carried out with a hammer and a figured rasp-punch. We cleaned the tibial and femoral components of the endoprosthesis with saline.

 We installed metal TEST prostheses of the tibial and femoral components on the corresponding sawdust and check the flexion and extension of the knee joint and the degree of tension of the ligamentous apparatus, which is physiological and does not require adjustment.

With the help of bone cement, the tibial and femoral components were fixed on the corresponding sawdust, and the platform was placed between them. The remaining cement was removed. After bending the knee joint to an angle of 20-40 ^o removed additional bone cement.

 After this, the joint cavities were washed with saline. Wound closure was performed.

 The control x-ray showed positive results of the operation. On the fourth day, the patient activated movements in the joint. By day 15, the patient completely bent the knee joint and walked with the help of crutches, proceeding to the operated leg. After 6.5 weeks, the patient walked without crutches with a full load on the operated leg. There are no complaints.

 A follow-up examination, conducted after 6 months, found that on the control radiographs the position of the components of the endoprosthesis is correct. The endoprosthesis is stable.

Example 2
Patient F, 44

 Diagnosis: cancer of the right knee joint.

Determined the direction of the mechanical axis of the femur of the right knee joint, in accordance with which the angle between the mechanical and anatomical axes of the femur is approximately 8 ^o .

 When the patient is on the operating table on the back, an hemostatic tourniquet is applied to the upper third of the femur of the left knee joint. An antibiotic is administered intravenously.

 The surgeon after opening the cavity of the knee joint assesses the condition of the condyles, synovial membrane, ligaments, cartilage and assesses the tension of the lateral ligaments and the degree of instability of the knee joint.

After that, the knee joint was transferred into flexion at an angle of 90 ^o .

 The channel is formed along the anatomical axis of the femur with a drill with a diameter of 8 mm to a depth of 5 cm, followed by indentation of the drill along its entire length.

Intramedullary nail is inserted into the formed channel, with respect to the axis of which a direction of the mechanical axis is formed corresponding to the right knee joint, making an angle equal to 8 ^o with the anatomical axis.

After that, the angle is adjusted to 8 ^o . When checking confirmed the intersection of the direction of the mechanical axis of the center of the femoral head and the correct choice of the angle of 8 ^o . After that, a resection guide is placed on the femur and a level of resection of the femur extending along a plane located proximal to the femoral condyles by 10 mm is determined. In accordance with this level, the femur is resected perpendicularly to the corrected direction of the mechanical axis along the plane crossing the distal section. When checking with glass, a good quality of the sawdust obtained and full adhesion of the surface of the sawdust to the glass were found. The resection level is sufficient.

 The dimensions of the femoral component are determined by a measuring template, which is fixed on the plane of the resulting sawdust.

 After that, a drill with a diameter of 5 mm with a stop through the holes in the measuring template is drilled into two channels in the femur for fastening the resection template or endoprosthesis and the resection template is fixed to the sawdust, and the anterior and posterior parts of the femur are resected and angled resections of the obtained sawdust are obtained .

 The control of the performed filings of the femur, which is carried out with a metal TEST prosthesis of the femoral component, established that the resection was carried out correctly. After that, the metal TEST-prosthesis is removed using a sliding hammer and a hook in the form of a plate.

When conducting preliminary resection of the proximal tibia, the tibia is positioned at an angle of 90 ^o to the table surface and is fixed in the forward position extended.

 Then, the level of preliminary resection is determined by the depth of the most destroyed tibial condyle and the resection is performed with a saw along a plane perpendicular to the anterior surface of the tibia.

 After that, the resulting sawdust is adjusted according to the degree of tension of the lateral ligaments. To do this, in an unbent state of the knee joint, a metal TEST prosthesis of the femoral component is installed on the distal sawdust of the femur, between which and a tibial sawdust, a polyethylene template with a height of 12.5 cm is first installed. In this case, the polyethylene template is moved between the metal TEST prosthesis of the femoral component and sawdust of the tibia, as a result of which a weak tension of the lateral ligaments was determined. When a polyethylene template with a height of 14.5 cm was installed on the sawdust of the femur, an insufficient tension of the lateral ligaments was established. When installing a polyethylene template 17.5 cm high on the thigh bone, they came to the conclusion that the tension of the lateral ligaments corresponds to the physiological norm. This height is chosen as the basis and is equal to the sum of the heights of the metal platform of the tibial component and the polyethylene platform of the endoprosthesis. According to the results of the adjustment, a final resection of the tibia was performed.

 The size of the tibial component was selected using a template with a hole mounted on the tibia sawdust with the condition that the outer surface of the template was completely located on the cortical surface of the resulting sawdust.

 A sized template was fixed on the surface of the tibia sawdust with two mounting peaks. The tibia tibia was advanced anteriorly and a small sleeve was first installed in the hole of the template under the drill with a diameter of 10 mm and a hole was drilled through the small sleeve with a drill in the tibia. After removing the small sleeve, a larger sleeve is installed in its place to form a bed under the protrusion on the leg of the tibial component. The final refinement of the bed was carried out with a hammer and a figured rasp-punch. We cleaned the tibial and femoral components of the endoprosthesis with saline.

 We installed metal TEST prostheses of the tibial and femoral components on the corresponding sawdust and checked the flexion and extension of the knee joint and the degree of tension of the ligamentous apparatus, which is physiological and does not require adjustment.

With the help of bone cement, the tibial and femoral components were fixed on the corresponding sawdust, and the platform was placed between them. The remaining cement was removed. After bending the knee joint to an angle of 20-40 ^o removed additional bone cement.

 After this, the joint cavities were washed with saline. Wound closure was performed.

 The control x-ray showed positive results of the operation. On the fourth day, the patient activated movements in the joint. By day 20, the patient completely bent the knee joint and walked with the help of crutches, proceeding to the operated leg. After 6 weeks, the patient walked without crutches with a full load on the operated leg. There are no complaints.

 A follow-up examination, conducted after 6.5 months, found that on the control radiographs the position of the components of the prosthesis is correct. The endoprosthesis is stable.

 The technical and economic effect of the proposed technical solution is to increase the physiological adequacy of the living knee joint with stable operation of the knee joint with an installed endoprosthesis while reducing the time of the operation and expanding its capabilities.

Claims (1)

The knee joint endoprosthetics method, which consists in the fact that the knee joint is inflected at an angle of 90 ^° , then a bone canal is formed in the femur along the anatomical axis, an intramedullary nail is inserted into it, relative to the axis of which a mechanical axis is formed and the mechanical direction is adjusted axis, after which the resection guide determines the level of resection, according to which femoral resection is performed through the distal section perpendicular to the direction of the mechanical axis of the bone, on the resulting sawdust, the measuring template is fixed with holes, which determine the size of the femoral component of the endoprosthesis, with the subsequent formation in the femur through the holes in the template of two channels for attaching the template for the resection or the femoral component and then performing this template according to the received measurements of the anteroposterior resections parts of the femur and angular resections of their sawdust, after which control is carried out, characterized in that the installation of the tibial component made in the form of a metal platform with an opening and a leg located between the femoral and tibial components, a polyethylene endoprosthesis platform, preliminary resection of the tibia is performed in the position advanced anteriorly through the proximal section, perpendicular to the anterior surface of the lower leg along the depth of the most destroyed condyle, after which the knee joint is extended in an unbent state adjustment of the resulting tibia sawdust, which is performed by installing metal on the thigh bone sawdust of a TEST prosthesis of the femoral component, between which a tibial sawdust is mounted and moved one of the polyethylene templates, and by the tension of the lateral ligaments, the height of the polyethylene template is selected, which is equal to the sum of the heights of the metal platform of the tibial component and the plastic platform of the endoprosthesis and corresponds to one of the size range 9 , 5-17.5 mm, according to the results of the correction, the final resection of the tibia is carried out, after which, using the template with the hole, the butt end is selected size of the tibial component with the condition that the outer surface of the template is completely positioned with a hole on the cortical surface of the resulting sawdust, after which this template is fixed on the sawdust, the tibia is advanced anteriorly and the bed under the leg is formed through the hole in the template, then using metal TEST prostheses the tibial and femoral components mounted on the corresponding sawdust, according to the degree of tension of the lateral ligaments, check the flexion and extension of the knee joint, followed by installation and fixing on sawdust of the corresponding components.

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