Ankle and foot compressor-distractor

Abstract

The invention relates to the field of medicine, and more particularly to traumatology and orthopaedics. A compressor-distractor for external fixation comprises: supports in the form of closed and / or open rings having holes and having lugs on the outer face thereof that are provided with holes for receiving fastening elements, the supports being connected to one another by threaded rods and repositioning assemblies; bone fixation elements; and also fastening elements. The compressor-distractor for external fixation is made up of the following interconnected components: a base unit encircling the shin; a module for fixation and movement of the bones of the hindfoot; and a module for fixation and movement of the bones of the forefoot. The technical result of the claimed compressor-distractor is that of simplifying and standardizing the design, and increasing the possibilities for treating ankle and foot injuries and disorders.

Description

[0001] Compression and Distraction Device for External Fixation for the Treatment of Injuries and Disorders of the Ankle and Foot

[0002] The invention relates to the field of medicine, in particular to the field of traumatology and orthopedics.

[0003] The human foot is the most complex segment of the skeleton biomechanically. It contains 28 bones connected to form a single skeleton and 34 interdependent joints, united into a single kinematic chain. The trajectories of its individual links, kinematic pairs, and three or more articulating links can be circles, ellipses, sinusoids, and even planes (the subtalar joint). Furthermore, the foot is the terminal segment of the human skeleton and bears a heavy load, necessitating the presence of a powerful ligament-aponeurotic sheath, whose role is to maintain the stability of the anatomical and biomechanical relationships and cushion the foot. The foot also has unique blood supply. The talus, for example, being an intermediate kinematic link between the shin and foot and bearing heavy loads, lacks its own vascular supply. Therefore, it is vulnerable and often, with improper manipulations, a serious complication occurs - aseptic necrosis of its block.

[0004] In developing promising means of external fixation for the treatment of foot injuries and diseases, it is necessary to solve four main problems: 1) restoration of the correct anatomical and biomechanical relationships in the ankle joint, 2) the hindfoot, 3) the forefoot and middle foot, and 4) the correct distribution of forces to overcome the resistance of its ligamentous-aponeurotic sheath.

[0005] With regard to the ankle joint, the capabilities of the external fixation device must ensure effective centralization of the talar trochlea within the ankle mortise, as well as correction of displacements or deformities of the anatomical structures of the distal tibia. In the hindfoot, the following tasks are typically addressed: correcting pronation-supination components, calcaneal rotation, correcting its angular displacements in the sagittal plane, and restoring its shape and size through osteotomy and measured fragment displacement. In the forefoot and midfoot, the following tasks are also addressed: correcting adduction-abduction, pronation-supination, and flexion-extension components, both through joint manipulation and bone osteotomy.The correct distribution of efforts in the apparatus to overcome the resistance of the ligamentous-aponeurotic sheath consists in the possibility of creating multidirectional, biomechanically justified efforts in order to eliminate displacements or deformations through stretching of the plantar-aponeurotic sheath of the foot, but without its excessive overstretching, compression of the joints or provoking secondary displacements and deformations.

[0006] The above highlights the complexity of developing external fixation devices for the treatment of ankle and foot injuries and conditions that meet these requirements. Current devices do not fully address these needs, often resulting in arthrosis, decreased shock-absorbing function of the foot, and secondary deformities, which often lead to patient disability. The anatomy and biomechanics of the foot dictate the need for customized and optimally adapted external fixation devices for this segment.

[0007] A method is known for treating fractures of the talus, including the application of an articulated compression-distraction apparatus containing a basic ring support, repositioning and fixation of the fracture, characterized in that two crossing needles are passed through the distal metaphysis of the tibia, or two Shantz bone screws are inserted into it, or a combination of a needle and a Shantz screw is used, which are fixed on the basic ring support, two needles are passed through the calcaneus perpendicular to the sagittal plane, they are fixed on the posterior half-ring of a closed hinged support consisting of two half-rings connected to each other by threaded rods with hinges installed in brackets at the ends of the half-rings, two crossing needles are passed through the bones of the midfoot and fixed on the anterior half-ring of the said closed hinged support, while the closed hinged support is connected to the basic ring support using pairs threaded rods,connected to each other by ball joints, spokes are passed through the fragments of the talus bone and secured to brackets mounted on the aforementioned closed hinge support.

[0008]

[0009] The method includes a support connected by pairs of threaded rods with hinges installed sequentially between them, with a closed hinged support. The closed hinged support consists of two half-rings: a posterior and anterior one, connected by threaded rods with sequentially installed hinges, mounted in brackets. A disadvantage of this known method is its complexity and the inability to treat both the forefoot and hindfoot.

[0010] A method is known for treating severe foot deformities in patients over 12 years of age with Charcot-Marie-Tooth disease (CMT), characterized by the fact that a Z-shaped achillotomy is performed percutaneously, a plantotomy is performed, and supports of an external fixation device (EFD) are mounted on the foot and lower leg, for this purpose, pins are passed through the bones of the lower leg and foot, the pins in a taut state are attached to the corresponding EFD supports, the EFD supports fixed to the foot and lower leg are connected to each other with the possibility of mutual movement, the EFD produce a smooth, dosed correction of the foot deformity, after eliminating the deformity, a stabilizing operation is performed, for this purpose, an arcuate incision is made along the outer surface of the foot under the outer malleolus, a three-joint arthrodesis is performed, articular cartilage is sparingly removed from the talonavicular, talocalcaneal, calcaneocuboid joints with a chisel, the foot is set in position hypercorrection of all existing components of foot deformity, fixing the talus,the calcaneus and the forefoot in a given position of the AVF, by attaching the spokes to the AVF supports, the AVF perform compression in the arthrodesis zone, then the tendon of the posterior tibial muscle is transplanted onto the cuboid bone, for this, four incisions are made, the first incision is made in the projection of the scaphoid and medial cuneiform bones, the second - 2 cm behind and 3-4 cm above the inner malleolus, the third - along the anterolateral surface of the lower third of the leg, the fourth - in the projection of the cuboid bone, from the first incision the tendon is stitched and cut off from the attachment site, from the second incision the tendon is pulled proximally, using forceps between the tibia bones make a channel and pull the end of the tendon from the second incision into the third incision, then bring the tendon distally to the foot from the third incision to the fourth, fix the tendon to the bone with an anchor with a thread retainer,The tendon is fixed in the achieved position of the foot by screwing the anchor fixator into the bone and tying the anchor threads to the threads passed through the tendon, the wounds are treated, the position of the foot is fixed in the achieved position with an external fixation device, after the fixation period has expired, the external fixation device is dismantled.

[0011]

[0012] The disadvantage of the known method is the complexity and limited design of the device in terms of the ability to treat the forefoot and hindfoot.

[0013] The technical objective of the claimed compression-distraction apparatus is to simplify the design and expand the possibilities for treating ankle and foot injuries.

[0014] The design of the claimed device is shown in the drawings:

[0015] Fig. 1 - Compression-distraction external fixation apparatus for the treatment of injuries and diseases of the ankle joint and foot.

[0016] Fig. 2 Rotary support.

[0017] a - disassembled

[0018] b - assembled

[0019] Fig. 3. Module for fixation and movement of the bones of the hindfoot

[0020] a - assembled module

[0021] b - support

[0022] Fig. 4 Module for fixation and movement of the bones of the forefoot

[0023] a - module disassembled

[0024] b - assembled module

[0025] Fig. 5 Front movement unit.

[0026] Fig. 6 Sagittal displacement node.

[0027] Fig. 7 Biaxial hinges.

[0028] The claimed compression-distraction apparatus for external fixation for the treatment of injuries and diseases of the ankle joint and foot (Fig. 1) consists of a base on the shin, modules for fixation and movement of the bones of the rear and front parts of the foot, connected to each other.

[0029] The shin base, in the preferred embodiment, consists of two rotary supports (item 1), fastened together by threaded rods (item 2).

[0030] The rotary support (Fig. 2) consists of coaxial internal (pos. 3) and external (pos. 4) parts assembled into each of the arc sectors. The internal and external parts of the support are mounted so as to be able to rotate relative to each other by means of any known mechanism, for example, a key with a toothed rim (pos. 5); the coaxial external part of the support is configured to be able to secure movement units and other elements, for example, by projections (pos. 6) on the external end, having openings (pos. 7) for securing the movement units. A plurality of openings (pos. 8) are made on the internal part for securing threaded rods and / or bone fixation elements.

[0031] The module for fixing and moving the bones of the rear foot (Fig. 3a) is a support for fixing the rear foot (pos. 8) with sagittal movement units (pos. 9), connected by means of two-axis hinge units (pos. 10) and threaded rods (pos. 11) with frontal movement units (pos. 12), installed on the outer part of the distal rotational support of the base on the lower leg (pos.

[0032] 13). The rearfoot fixation support (Fig. 3 b) is made in the form of an open ring with elongated parallel ends (pos. 14) and projections (pos. 15) on the outer end, having holes (pos. 16) for fastening elements. Sagittal movement units (pos. 9) are attached to the projections.

[0033] The forefoot bone fixation and movement module (Fig. 4) is a forefoot fixation support (Item 17, Fig. 4 b) with a movement unit (Item 18, Fig. 4 b) connected by means of threaded rods (Item 19) and biaxial hinges (Item 20, Fig. 4 b) with a movement unit (Item 21) secured to a projection of the outer part of the proximal rotational support of the base on the shin (Item 22). The forefoot fixation support has the shape of a semicircle with projections at the ends (Item 23, Fig. 4 a) and a serrated groove (Item 24) along the outer end for fastening the movement unit (Item 18). The movement unit on the forefoot fixation support is a housing (Item 25) in the cavity of which a threaded rod (Item 26) is installed. The movement unit on the proximal rotary support is a housing (pos. 27), in the cavity of which a threaded rod (pos. 28) is installed. The ends of the threaded rods protruding from the housings are secured by means of nuts (pos.29) two-axis hinges (pos. 20) are fixed, connected by threaded rods (pos.

[0034] 19) with fixing nuts (pos. 30). The housings of the movement units are made with holes (pos. 31) for fastening to the supports by means of bolts (pos. 32) with nuts (pos.

[0035] 33) and holes (pos. 34) for installing keys with a toothed rim (pos. 35) with a locking nut (pos. 36) on the free end.

[0036] The projections 6, 15, 23 along the outer contour of the supports are made congruent, projectively coincide and have the ability to rigidly attach the housing units of the movement and other elements, for example, bolts, hinges and threaded rods, to the support, and the surface of the supports is made with a plurality of holes to enable rigid fixation of bone fixation elements and / or threaded rods on them.

[0037] The front movement unit (Fig. 5) consists of a housing (pos. 37) with openings, a toothed rack (pos. 38), the curved ends (pos. 39) of which are provided with openings (pos. 40) and a movement mechanism, for example, a key with two toothed rims (pos. 41). When assembled, the toothed rack is located inside the housing with the possibility of longitudinal movement using the movement mechanism, for example, when turning the key with toothed rims. For ease of movement monitoring, a window (pos. 42, Fig. 1) can be made on the housing, and a scale (pos. 43, Fig. 1) on the rack.

[0038] The sagittal movement unit (Fig. 6) consists of a housing (pos. 44) with holes, a straight toothed rack (pos. 45), the ends of which are provided with holes (pos.

[0039] 46) and a movement mechanism, for example, a key with two toothed rims (pos. 47). When assembled, the toothed rack is located inside the housing with the possibility of longitudinal movement using the movement mechanism, for example, when turning the key with toothed rims. For ease of movement control, a window (pos. 48, Fig. 1) can be made on the housing, and a scale (pos. 49, Fig. 1) on the rack.

[0040] The supports of the modules of the front and rear sections of the foot are connected by threaded rods (pos. 50, Fig. 1) with two-axis hinges (pos. 51, Fig. 1), secured to the supports by means of bolts and nuts (pos. 52, Fig. 1).

[0041] The device provides for the use of three types of two-axis cardan joints (Fig. 7) - with two perpendicular smooth holes (Fig. 7 a), perpendicular smooth and threaded holes (Fig. 7 b) and two coaxial threaded holes (Fig. 7 c).

[0042] For the sake of simplicity, the drawings shown here show biaxial hinges; however, it is obvious to a specialist that they can be similar in capabilities to a prefabricated unit consisting of several parts connected together with bolts and nuts.

[0043] Osteosynthesis of the lower leg and foot using the proposed compression-distraction apparatus for external fixation is carried out as follows.

[0044] Based on X-ray images and the actual dimensions of the patient's limb, the diameter, number, and type of supports are selected. Typically, these include two rotational supports (Fig. 2), one support for fixing the hindfoot (Fig. 3), and at least one support for fixing the forefoot (Fig. 4). The rotational supports are assembled from two inner coaxial half-rings and two outer coaxial half-rings, fastened together with bolts and nuts. The connections between these rings must be installed perpendicular to each other.

[0045] Under sterile conditions, under general or spinal anesthesia, two crossing pins (Item 53, Fig. 1) are inserted through the distal metaphysis and the middle third of the tibia and secured with pin-lock bolts (Item 54, Fig. 1) under tension in the holes in the inner parts of the rotation bearings. The bearings are connected to each other with three or four threaded rods. Next, two frontal movement assemblies are installed and secured on the anterior and posterior projections of the distal rotation bearing.

[0046] Next, at least two crossing pins (Item 55, Fig. 1) are passed through the calcaneus and secured with pin-lock bolts (Item 56, Fig. 1) in a taut state in the rearfoot fixation support. If necessary, additional pins are passed through the talus and also secured in the same support. Two sagittal translation units are installed and secured on the lateral projections of the rearfoot fixation support. The ends of the toothed racks of the frontal and sagittal translation units are connected to each other by means of biaxial hinge assemblies and threaded rods such that the toothed racks of the distal rotational support are strictly perpendicular to the toothed racks of the rearfoot fixation support.

[0047] At least one spoke (pos. 57, Fig. 1) is passed through the bones of the forefoot in the transverse direction, and is secured with spoke-fixing bolts (pos. 58, Fig.

[0048] 1) Secure in a taut position in the holes of the forefoot fixation support. If necessary, additional pins can also be passed through the midfoot bones and secured to the same support. The forefoot fixation support is connected to the anterior projection of the outer portion of the proximal rotational support via the fixation module and forefoot bone movement assemblies. The ends of the forefoot and hindfoot fixation supports are connected to each other via threaded rods and biaxial hinge assemblies.

[0049] In its present form, the proposed compression-distraction device is ready for use. Turning the head of the key with two toothed rims of the frontal movement unit in one direction or another will cause the foot to shift left or right.

[0050] Turning the head of the key with two toothed crowns of the sagittal movement unit in one direction or another will lead to a forward and backward displacement of the foot.

[0051] Paired compression-distraction along threaded rods with biaxial hinge assemblies connecting the distal rotation support with the rearfoot fixation support will result in rearfoot rotation in the frontal or sagittal planes.

[0052] Turning the head of the proximal rotation bearing camshaft will result in adduction or abduction of the forefoot.

[0053] Turning the head of the distal rotation bearing camshaft will result in adduction or abduction of the hindfoot.

[0054] Rotating the head of the cam-head screw of the forefoot fixation and translation module will produce a pronation-supination effect on the forefoot. This effect can be enhanced by manipulating the 19-pins (compression on one and distraction on the other, and vice versa).

[0055] Distraction-compression along rods with biaxial hinges at the ends is used to overcome the resistance of the ligament-aponeurotic sheath of the foot and adduction-abduction of its forefoot.

[0056] The device allows for movement of the supports to stabilize the hindfoot and forefoot within any desired range and direction. Depending on the placement of the pins and the direction of traction on the supports, the calcaneus and talus bones or their fragments can be moved in all planes, along any linear or angular trajectory, lengthened, defects corrected, and deformities corrected. The device also allows for foot lengthening through osteotomy of the midfoot bones, correcting their deformities and displacements in all three planes.

[0057] Thus, the claimed device has a high standardization of individual, duplicating elements and units, is easy to install and perform dosed manipulations, and also allows for their precise visual control.

[0058] The technical result of the claimed compression-distraction apparatus is the simplification and unification of the design, expanding the possibilities for treating injuries and diseases of the ankle joint and foot.

Claims

Invention formula 1. A compression-distraction external fixation device for the treatment of injuries and diseases of the ankle joint and foot, containing supports in the form of closed and / or open rings with openings and projections on the outer end, having openings for fastening elements, connected to each other by means of threaded rods and repositioning units, fixing bone elements, as well as fastening elements, while characterized in that it consists of a. bases on the shin in the form of two supports, the outer part of which is made with projections on the outer end, having holes for fastening elements, fastened together with threaded rods; b. a module for fixing and moving the bones of the rear foot, which is a support for fixing the rear foot with sagittal movement units connected by means of biaxial hinge units and threaded rods with frontal movement units mounted on a distal rotational support of the base on the lower leg, wherein the support for fixing the rear foot is made in the form of an open ring with elongated parallel ends and projections on the outer end, having openings for fastening elements; c. a module for fixing and moving the bones of the forefoot, which is a support for fixing the forefoot with a movement unit connected by means of threaded rods and biaxial hinges with a movement unit secured on a projection of the outer part of the proximal rotational support of the base on the shin, wherein the support for fixing the forefoot has the form of a semicircle with projections at the ends and a serrated cut along the outer end for fastening the movement unit, the movement unit on the support for fixing the forefoot is a housing in the cavity of which a threaded rod is installed, and the movement unit on the proximal rotational support is a housing in the cavity of which a threaded rod is installed; wherein the forefoot fixation support is connected to the hindfoot fixation support by means of threaded rods with biaxial hinges.

2. A compression-distraction apparatus for external fixation for treating injuries and diseases of the ankle joint and foot according to claim 1, characterized in that at least one of the supports of the base on the shin is made of coaxial internal and external parts installed with the possibility of rotation relative to each other, the coaxial external part of the rotary support is formed from arc sectors and is made with projections on the external end, having openings for fastening elements, and a plurality of openings are made on the surface of the internal part.

3. A compression-distraction external fixation device for the treatment of injuries and diseases of the ankle joint and foot according to paragraphs 1-2, characterized in that the frontal movement unit consists of a housing with openings, a toothed rack, the curved ends of which are provided with openings, and a mechanism for moving the rack inside the housing.

4. A compression-distraction external fixation device for the treatment of injuries and diseases of the ankle joint and foot according to paragraphs 1-3, characterized in that the sagittal movement unit consists of a housing with holes, a straight toothed rack, the ends of which are provided with holes, and a mechanism for moving the rack inside the housing.

5. A compression-distraction apparatus for external fixation for the treatment of injuries and diseases of the ankle joint and foot according to paragraphs 1-4, characterized in that a window is made on the housings of the frontal and sagittal movement units, and a scale is made on the toothed rack.

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