RU225586U1 - Guide for ankle replacement - Google Patents

Abstract

The utility model includes a support, resection modules, a plate for fixing the foot, a heel pad, characterized in that the support module consists of a base with two posts; the base has two through grooves for moving the thigh support with posts, movable bushings and a platform with eyes; on the base posts there are bushings connected to each other by a jumper with a guide bushing on which the shin support is located; a supporting rod in the form of a rod with a transverse rectangular cross-section passes through the guide bushing; scales with dimensional divisions are applied to the side surfaces of the supporting rod; distally on the supporting rod on movable bushings there is a support platform with a heel pad in the form of a vice, and a plate for resting the foot, having transverse slots located from each other at a distance equal to the distance between the holes of two corners with eyes; the corners are fixed to the foot support plate with screws; in the lower part the plate has two longitudinal slots for fixing it to the heel pad; all elements of the support module are fixed to each other with screws; in front of the support platform and behind the plate for resting the foot on the supporting rod, there are two remote racks of the resection module, which have U-shaped recesses corresponding to the external dimensions of the supporting rod and through grooves for moving an H-shaped panel into them, which, in turn, has a through guide a groove for moving an L-shaped stand in it with a vertical through groove for moving a resection block in it, consisting of two fixing parts, a resection plate with a groove and four holes for fixing to it from the inside using screws of a replaceable element, the surface of which corresponds to the surface resected talus; all elements of the resection module are fixed to each other with screws; a module for pulling the foot is fixed to the distal sleeve of the support platform using screws, which consists of two rods, to which an H-shaped crossbar is fixed using screws, having a hole for a pulling screw with a handle, passing into the hole and channel inside the distal section of the support rod and abutting into a cone socket.

Description

The utility model relates to medicine, namely to traumatology, orthopedics and oncology, and can be used for ankle joint replacement (EGS) in patients with osteoarthritis of the ankle joint of various etiologies, tumors of the lower third of the tibia and ankle joint area.

During EGS, it is extremely important to position the limb in the correct position, accurately perform resection of the tibia and articular surface of the talus, and correctly install the components of the endoprosthesis. Little is known about special systems and clamps for EGS.

The Hintermann H2 guide system for installation of an orthopedic prosthesis is known, consisting of a retaining claw-shaped latch attached to the patient’s lower leg, a guide rod (conductor body) and a resection module at its distal end [1].

The disadvantage of the resection module is its lack of stability due to the non-invasive nature of fixation only due to a claw-shaped latch. When using the system, it is not possible to perform segmental resection of the tibia. The design does not imply a template resection of the medial malleolus and requires manual technique, which generally causes gross errors in EGS.

The Infiniti guide system for installation of an ankle joint endoprosthesis is known, consisting of a leveling arc-rod fixed percutaneously in the crest of the tibia with a resection module at the end, adjustable in height and frontal plane [2].

The disadvantage of the design is the monolithic resection template, which does not allow resection of the tibia and talus bones separately; inability to perform segmental resection of the tibia. Violation of the technique for installing the resection module of the system can lead to gross errors in the spatial arrangement of prosthetic components, their migration and subsequent instability.

A known guide system with a resection module is a U-shaped frame consisting of four support rods, a foot support plate, a heel pad and a retaining block for the calf muscle of the leg. The use of the system involves transosseous fixation of the calcaneus, tibia and talus under image intensifier control. Resections of the talus and tibia are performed using a template from the lateral side, which requires an oblique osteotomy of the tibia [3]. We took this system as a prototype.

The technical result of the utility model will be the creation of a guide system for ankle joint replacement.

This result is achieved by the fact that the support module consists of a base with two posts; the base has two through grooves for moving the thigh support with posts, movable bushings and a platform with eyes; on the base posts there are bushings connected to each other by a jumper with a guide bushing on which the shin support is located; a supporting rod in the form of a rod with a transverse rectangular cross-section passes through the guide bushing; scales with dimensional divisions are applied to the side surfaces of the supporting rod; distally on the supporting rod on movable bushings there is a support platform with a heel pad in the form of a vice and a plate for resting the foot, having transverse slots located from each other at a distance equal to the distance between the holes of two corners with eyes; the corners are fixed to the foot support plate with screws; in the lower part the plate has two longitudinal slots for fixing it to the heel pad; all elements of the support module are fixed to each other with screws; in front of the support platform and behind the plate for resting the foot on the supporting rod, there are two remote racks of the resection module, which have U-shaped recesses corresponding to the external dimensions of the supporting rod and through grooves for moving an H-shaped panel into them, which, in turn, has a through guide a groove for moving an L-shaped stand in it with a vertical through groove for moving a resection module in it, consisting of two fixing parts, a resection plate with a groove and four holes for fixing to it from the inside using screws of a replaceable element, the surface of which corresponds to the surface resected talus; all elements of the resection module are fixed to each other with screws; a module for pulling the foot is fixed to the distal sleeve of the support platform using screws, which consists of two rods, to which an H-shaped crossbar is fixed using screws, having a hole for a pulling screw with a handle, passing into the hole and channel inside the distal section of the support rod and abutting into a cone socket.

The guide system for ankle replacement includes a support module, a resection module, and a foot extension module. The modules are structurally interconnected; most elements of the modules are movable, removable and easily adapt to the specific dimensions of the patient’s limb and clinical situation.

Due to the movable bushings on the racks, free movement of the support areas for the thigh and lower leg is possible. This allows you to adjust both the height of the limb on the operating table and giving the leg the position necessary for manipulation on the proposed system.

The support platform with a heel pad and a plate for resting the foot is mounted on movable bushings and moves freely along the supporting rod, which makes it possible to adjust the location of these elements depending on the individual length of the limb. The corners on the foot support plate can be secured to it with screws at different levels and distances depending on the individual size of the patient’s foot.

The elements of the system provide for the possibility of additionally strengthening the limb on it in the correct position. Through the eyelets of the platform it is possible to secure the thigh using tapes. The foot can additionally be reinforced with tapes through the eyelets of the corners attached to the plate to support the foot. The heel is held in a heel pad, which optimally fixes it like a vice.

The presence of scales with dimensional divisions on the side surfaces of the supporting rod allows you to measure and remember the distance from the guide sleeve to the proximal sleeve of the support platform after fixing the limb. And subsequently, after resection of the bones, set this distance between the elements of the system in order to avoid gross changes in the length of the limb when installing the components of the endoprosthesis.

The elements of the resection module are mobile and move relative to each other due to the presence of through grooves in them in different planes. The location of the fixing elements of the resection module in different planes also allows the latter to have several degrees of freedom.

The replacement element of the resection module is manufactured individually on a 3D printer based on data from a preoperative instrumental study (CT scan of the patient’s talus) so that the relief of its surface corresponds to the surface of the resected talus. The replacement element is securely fixed to the resection plate using four screws. After aligning the surfaces of the replaceable element of the system and the patient’s talus through the resection groove of the plate, its precise resection can be performed - this allows you to clearly install the talus component of the endoprosthesis without additional filings, fitting templates and other actions.

The module for traction of the foot due to the movement of the traction screw with a handle allows you to free up space intraoperatively due to the displacement of the foot distally, which allows you to easily compare the upper part of the tibial component of the endoprosthesis and its body without damaging the tissue, which is often quite difficult to do, and subsequently due to the reverse movement screw to achieve congruence of the endoprosthesis components.

The guide system for ankle replacement includes a support module, a resection module, and a foot extension module. The support module consists of a base with two posts; the base has two through grooves for moving the thigh support with posts, movable bushings and a platform with eyes.

The base posts have bushings connected to each other by a jumper with a guide bushing on which the shin support is located. A supporting rod in the form of a rod with a transverse rectangular cross-section passes through the guide bushing; Scales with dimensional divisions are applied to the side surfaces of the supporting rod. Distally on the supporting rod, on movable bushings, there is a support platform with a heel rest, shaped like a vice, and a plate for resting the foot, having transverse slots located from each other at a distance equal to the distance between the holes of two corners with eyes. The corners are fixed to the foot support plate with screws. In the lower part, the plate has two longitudinal slots for fixing it to the heel pad; All elements of the support module are fixed to each other with screws.

In front of the support platform and behind the plate for resting the foot on the supporting rod, there are two remote racks of the resection module, which have U-shaped recesses corresponding to the external dimensions of the supporting rod and through grooves for moving an H-shaped panel into them, which, in turn, has a through guide a groove for moving an L-shaped stand in it with a vertical through groove for moving a resection module in it, consisting of two fixing parts, a resection plate with a groove and four holes for fixing to it from the inside using screws of a replaceable element, the surface of which corresponds to the surface resected talus. All elements of the resection module are fixed to each other with screws.

A module for pulling the foot is fixed to the distal sleeve of the support platform using screws, which consists of two rods, to which an H-shaped crossbar is fixed using screws, having a hole for a pulling screw with a handle, passing into the hole and channel inside the distal section of the support rod and abutting into a cone socket.

A guide system for ankle replacement is shown in FIG. 1-3. In fig. 1 the system is shown from the inside; in FIG. 2 from the outside. In fig. Figure 3 shows a detailed view of the system from the side of the plantar surface.

The support module consists of a base 1 with two posts 2. The base 1 contains two through grooves 3 for moving the thigh support 4 with posts 5, movable bushings 6 and a platform 7 with eyes 8 for fixing the hip.

Along the uprights 2 of the base 1, bushings 9 move, connected to each other by a jumper 10 with a guide bushing 11, on which the shin support 12 is located. A supporting rod 13 passes through the guide bushing 11 in the form of a rod with a transverse rectangular cross-section, while on the side surfaces of the supporting rod 13 scales with dimensional divisions are applied.

Distally on the supporting rod 13 on movable bushings 14 there is a support platform 15 with a heel pad 16, which looks like a vice, and a plate for resting the foot 17. The plate 17 has transverse slots 18 located from each other at a distance equal to the distance between the holes of two corners 19 with eyes 20. Angles 19 are fixed to the foot rest plate with 17 screws. In the lower part, the plate 17 has two longitudinal slots 21 for fixing it to the heel pad 16. All elements of the support module are fixed to each other with screws.

In front of the support platform 15 and behind the plate for resting the foot 17 on the supporting rod 13 there are two remote stands 22 of the resection module. The racks 22 have U-shaped recesses 23 corresponding to the external dimensions of the supporting rod 13 and through grooves 24 for moving the H-shaped panel 25 in them. The H-shaped panel 25 has a through guide groove 26 for moving the L-shaped rack 27 in it, having vertical through groove 28 for moving the resection module in it.

The resection module consists of two fixing parts 29, a resection plate 30, which has a through resection groove 31 and four holes 32 for fixing to it from the inside using screws of the replaceable element 33. The surface relief of the replaceable element 33 corresponds to the surface of the talus being resected. All elements of the resection module are fixed to each other with screws.

A module for pulling the foot is fixed to the distal sleeve 14 of the support platform 15 using screws, which consists of two rods 34, to which an H-shaped crossbar 35 is fixed using screws, having a hole for a pulling screw 36 with a handle 37 passing into the hole and channel inside distal section of the supporting rod and resting on the conical socket.

The guide system for ankle replacement is used as follows. The system support module is installed on the operating table. The optimal position of the leg on it is determined, convenient for surgeons and necessary for subsequent manipulations. Determine the position of the thigh support 4, the height and position of its platform 7. Determine the height and optimal location of the shin support 12. Taking into account the length of the limb, install and fix the support platform for the foot 15. Taking into account the size of the patient’s foot, install and fix it on the plate for resting the foot 17 corners 19.

The limb is fixed to measure the distance between the guide sleeve 11 and the proximal sleeve 14 of the support platform 15. To do this, the patient’s thigh is fixed using tapes passed through the eyes 8 of the platform 7 of the thigh support 4. The patient’s foot is fixed using tapes passed through the eyes 20 of the corners 19 plates for resting the foot 17. Additionally, the heel is fixed in the vice of the heel pad 16. Using a scale on the inside or outside of the supporting rod 13, the required distance is measured and stored.

Start performing the operation. For ease of manipulation, the foot support plate 17 can be temporarily disconnected from the heel pad 16 and the foot support pad 15.

The lower part of the tibia is visualized and isolated along the required length, with the interosseous membrane, deltoid ligament and joint capsule being cut off from it. An osteotomy of the tibia is performed. The posterior group of muscles of the lower leg is separated: the long flexor of the big toe, along with the soleus and gastrocnemius muscles. The lower segment of the tibia is dislocated and removed.

If the plate for supporting the foot 17 was removed, then it is again fixed to the heel pad 16, providing additional fixation of the foot with tape through the eyes 20 of the corners 19. The talus along the perimeter is freed from soft tissues. The resection module is installed. All its elements are positioned and fixed until the surface of the replaceable element 33 is completely aligned with the patient’s talus. Through the hole of the resection groove 31 of the resection plate 30, a guide channel is first drilled in the talus, then through the resection groove 31 of the resection plate 30, a precise resection of the talus is performed using a saw. The resection module is removed.

The talus component of the endoprosthesis is placed with its lower surface, covered with hydroxyapatite, on the sawdust of the talus, fixing it with screws. The body of the tibial component of the endoprosthesis together with the liner is congruently compared with the articular surface of the talus component by passing through the through grooves of the restrictive rod.

After preparing the medullary canal of the tibia, an intramedullary stem is implanted into it, previously connected through a Morse cone to an extension module, which, in turn, is connected through a Morse cone to the upper part of the tibial component.

Before comparing the upper part of the tibial component with its body, a traumatic situation often arises associated with a lack of intraoperative space, tension and tissue injury. Therefore, before this, it is advisable to install a module of the guidance system for stretching the foot. Due to the movement of the pulling screw 36, the foot moves distally, which makes it possible to easily compare the upper part of the tibial component of the endoprosthesis and its body without damaging the tissues. Subsequently, due to the reverse movement of the screw 36, congruence of the components of the endoprosthesis is achieved.

Again, using the scale of the supporting rod 13, measure the distance between the guide sleeve 11 and the proximal sleeve 14 of the support platform 15. The preservation of the original length of the limb or its change is noted, which may require orthopedic correction.

Remove the module for stretching the foot, the plate for supporting the foot 17, release the heel from the heel pad 16. Perform passive movements in the joint, check its stability, after which the soft tissues and skin are sutured layer by layer.

The use of a guide system for ankle replacement is illustrated by a clinical example.

Patient S., 55 years old, was in the hospital with a diagnosis of “Old improperly consolidated fracture of the bones of the left leg in the lower third. Post-traumatic defect of the lower third of the right tibia. Post-traumatic osteoarthritis of the ankle joint stage IV.” The patient underwent surgery: Removal of the articular end of the tibia. Endoprosthetics of the left ankle joint using the proposed guide system.

The operation proceeded without technical difficulties. The surgeons noted the convenience of position and fixation on the proposed limb system, the accuracy of resection of the talus, which did not require additional filings and processing of the receiving bed. Ease of use of the module for stretching the foot, which made it possible to seamlessly combine the elements of the endoprosthesis. Possibility of pre- and postoperative control of limb length.

In the postoperative period, immobilization was carried out in a rigid splint for 6 weeks; there were no complications such as instability of components, dislocations, or wound infections. A follow-up examination after 12 months revealed no signs of instability of the endoprosthesis components.

It is advisable to use a guide system for ankle joint replacement when performing operations in traumatology, orthopedic, and oncology hospitals.

INFORMATION SOURCES

1. https://www.vilex.com/hintermann-series-h2.html.

2. https://www.wright.com/footandankleproducts/infinity-total-ankle-system

3. https://www.zimmerbiomet.com/content/dam/zimmer-biomet-OUS-Surg-techniques/foot-and-ankle/trabecular-metal-total-ankle-surgical-technique.pdf

Claims (1)

A guide for ankle joint replacement, including a support module, a resection module for the talus, a plate for resting the foot, a heel pad, characterized in that the support module consists of a base with two posts; the base has two through grooves for moving the thigh support with stands, movable bushings and a platform with eyes for tapes that fix the thigh; on the base posts there are bushings connected to each other by a jumper with a guide bushing on which the shin support is located; a supporting rod in the form of a rod with a transverse rectangular cross-section passes through the guide bushing; scales with dimensional divisions are applied to the side surfaces of the supporting rod; distally on the supporting rod on movable bushings there is a support platform with a heel pad in the form of a vice, and a plate for resting the foot, having transverse slots located from each other at a distance equal to the distance between the holes of two corners with eyes for tapes that fix the foot; the corners are fixed to the foot support plate with screws; in the lower part the plate has two longitudinal slots for fixing it to the heel pad; all elements of the support module are fixed to each other with screws; in front of the supporting platform and behind the plate for resting the foot on the supporting rod, there are two remote racks of the resection module, which have U-shaped recesses corresponding to the external dimensions of the supporting rod, and through grooves for moving an H-shaped panel into them, which, in turn, has a through a guide groove for moving an L-shaped stand with a vertical through groove for moving a resection block for the talus in it, consisting of two fixing parts, a resection plate with a resection groove and four holes for fixing to it from the inside using screws of a replaceable element , the surface of which corresponds to the surface of the resected talus; all elements of the resection module are fixed to each other with screws; a module for pulling the foot is fixed to the distal sleeve of the support platform using screws, which consists of two rods, to which an H-shaped crossbar is fixed using screws, having a hole for a pulling screw with a handle, passing into the hole and channel inside the distal section of the support rod and abutting into a cone socket.