TREATMENT OF KNEE DISORDERS IN VETERINARY MEDICINE

Abstract

The present invention provides an external brace, an orthosis, for treating disorders of joints in dogs and cats. The most relevant veterinary indication is a hock joint brace to treat cranial cruciate disease in dogs.

Claims

1-17. (canceled)

18. A brace adapted for application to the hock joint of an animal, particularly a dog, comprising a first main component comprising a hard shell and a padding and a second main component comprising a hard shell and a padding, wherein the first and the second main components are connected by at least two sets of straps into a clam-shell-like construct around the joint thereby limiting its flexion-extension range of movement, wherein the first main component is adapted to fit the caudo-plantar aspect of the distal hind limb and the second main component is adapted to fit the cranio-dorsal aspects of the distal hind limb, and wherein the hock joint angle is close to full extension.

19. The brace according to claim 18, wherein the hock joint angle is in a range from 145 to 170 degrees.

20. The brace according to claim 18, which is adapted for application to the hock joint of a dog.

21. The brace according to claim 18, wherein the hock joint angle is about 155 degrees.

22. The brace according to claim 18, wherein the hard shell of the caudo-plantar component is provided with an opening at the position of the calcaneus.

23. The brace according to claim 18, wherein the length of the straps is adjustable.

24. The brace according to claim 18, wherein the straps comprise at least one velcro band set comprising a plurality of velcro bands.

25. The brace according to claim 24, wherein the straps comprise at least one velcro band set comprising three velcro bands.

26. The brace according to claim 18, wherein the hard shell of the first main component and/or the hard shell of the second main component is made from a thermoplastic material.

27. The brace according to claim 26, wherein the thermoplastic material is a composite of wood and a biodegradable polymer.

28. The brace according to claim 18, wherein the distal end of the hard shell of the caudo-plantar main component comprises a removable rubber pad.

29. The brace according to claim 28, wherein the removable rubber pad is provided in several different lengths.

30. The brace according to claim 18, adapted to treat cranial cruciate ligament disease of the stifle.

31. The brace according to claim 18, made in several sizes for animals, particularly dogs.

32. A method for the treatment of a joint disorder in an animal comprising applying to the hock joint a brace comprising a first main component comprising a hard shell and a padding and a second main component comprising a hard shell and a padding, wherein the first and the second main components are connected by at least two sets of straps into a clam-shell-like construct around the joint thereby limiting its flexion-extension range of movement, wherein the first main component is adapted to fit the caudo-plantar aspect of the distal hind limb and the second main component is adapted to fit the cranio-dorsal aspects of the distal hind limb, and wherein the hock joint angle is close to full extension.

33. The method according to claim 32, wherein the disorder is stifle disorder, and the brace is applied to the hock joint.

34. The method according to claim 33, wherein the stifle disorder is a cranial cruciate ligament disease of the stifle.

35. The method according to claim 32, wherein the animal is a dog.

37. The method according to claim 32, wherein the hock joint angle is in the range from 145 to 170 degrees.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows orthogonal views of an inventive brace.

[0027] FIG. 2 is a photograph of the brace on the hock of a dog.

[0028] FIG. 3 is a photograph of the brace with two main components separated.

[0029] FIG. 4 is a photograph of the brace configured to hold the hock joint in full extension.

[0030] FIG. 5 is a photograph of the brace main component without padding.

[0031] FIG. 6 is a photograph of the ground-contacting rubber pads.

DETAILED DESCRIPTION

[0032] This invention is based, at least in part, on in vitro experiments and clinical observations that have helped us identify the fundamental causes of the slow process of degradation of the CrCL in the dog. Our experimental work with dog cadavers has shown a strong destabilizing effect of the gastrocnemius muscles. The force that these muscles exert can be greatly reduced by shortening the muscle working length by extending the hock joint. Since the dog is free to use its distal limb, the moment exerted on the hock joint due to ground reaction must be transferred to the tibia, which defines the first of two main mechanical functions of the braceresisting the moment by reactive forces to the tibia shaft and the metatarsals. In mechanical terminology, this is referred to as four-point-bending. To reduce the magnitude of the force acting upon the hock joint resulting in gastrocnemius muscle contraction, the second main mechanical function of the brace modifies the point of contact to the ground and shifts the reaction force vector closer to the hock joint thereby reducing the flexion moment, which in turn reduces the magnitude of the force that the gastrocnemius muscle attempts to resist through muscle contraction. In mechanical terminology, this is referred to as ground reaction force vector alignment.

[0033] Our results are generally applicable in veterinary medicine, not only for dogs, but also for other animal species such as cats.

[0034] FIG. 1 shows a photograph of the brace 100 in orthogonal views: (a) is the caudal view; (b) is the lateral view; (c) is the cranial view. The brace is composed of two rigid padded components connected by at least two sets of straps into a clam-shell-like construct covering the caudo-plantar and cranio-dorsal aspects of the distal hind limb.

[0035] The first main component 1 of the brace 100 is a hard shell 2 shaped to fit the caudo-plantar aspect of the metatarsal bases of the distal hind limb. The purpose of the specific shape of the caudo-plantar component is to disperse forces over a larger area of soft tissue to reduce soft-tissue injury. Shell 2 may be formed from a thermoplastic material. The distal part 3 of the hard shell 2 may be concave, formed to support the metatarsals, creating a contact point to the ground e.g., via rubber pad 13 caudal to the central paw pad. The purpose of contacting the ground caudal to the central paw pad is to modify the ground reaction force vector alignment beneficially closer to the hock joint to reduce the magnitude of the hock joint flexion moment. The proximal part 4, wraps around the caudal aspect of the distal tibia, distal to the insertion points of the hamstrings along the medial aspect of the proximal tibia. The purpose of part 4 location is to eliminate hamstring contact to the proximal caudal edge of the brace 100 that results in soft-tissue sores and distal brace migration leading to destabilizing of the hock joint. In the transition zone from the proximal part 4 to the distal part 3 of the hard shell 2, there is an opening 5 corresponding to the anatomical structure of calcaneus. The purpose of opening 5 is to remove the risks of pressure sores of the soft tissue covering the calcaneus. Padding 6 covers the inner side of the brace component 1. The padding establishes contact to the distal caudal gastrocnemius tendon and proximal aspect of the calcaneus intentionally to create brace 100 purchase and suspension to the pelvic limb and resisting the device distally migrating off the limb resulting in complete destabilization.

[0036] The second main component of brace 100 is a tongue-shaped cranio-dorsal cover 10 of the hock joint. It may also be formed from a thermoplastic material. The proximal surface of the cranial cover 10 is shaped to fit the tibial crest located on the proximal cranial tibia and the tibial tuberosity. The purpose of this shape is to eliminate soft-tissue wounds commonly associated with bandages at this location of the pelvic limb. The transition zone of the cranial cover 10 is shaped to eliminate contact to the cranial tibialis tendon located on the distal tibia and the insertion of the cranial tibialis tendon located on the proximal cranial hock. The purpose of this transition zone shape is to reduce soft-tissue injury to the skin covering the tendon and eliminate direct tendon pressure resulting in pain. The distal surface of the cranial cover 10 is shaped to fit the curvature of the metatarsals and alleviate contact and pressure upon the digital extension tendons. Additionally, the distal end of the cranial cover 10 terminates at the distal surface of the metatarsals purposely so that the digits are not restricted during gait. Padding 12 covers the backside of shell 11.

[0037] The main components 1 and 10 of the brace 100 are connected by two sets of straps 20 and 21 at the proximal and the distal aspects of the brace. Each set of straps may be made of 3 strips of velcro bands making two pairs of connections. One pair connects one side of component 1 to component 10, and the other pair the other side of component 1 to component 10. In this manner, the position of the tongue 10 is fixed relative to the main component 1 both in a sideways position and in distance from proximal to distal. The location of the proximal and distal straps purposely establishes the connection between component 1 and component 10 resulting in the creation of the 4-point bending control system. The rubber pad 13 is fixed to the distal end of the shell 2, e.g., by two screws 14.

[0038] FIG. 2 shows the brace 100 applied to the hock joint of a dog. This is a small brace on a dog of about 18 kg bodyweight. Six sizes of the brace from XX-Small to X-Large may cover dogs from toy to giant breeds.

[0039] FIG. 3 shows the two components of the brace separated. The velcro band 22 of the proximal set 20 of straps is a loop-type. Band 23 is loop-type on the inside and hook-type on the outside. Band 24 covers the full width of tongue 10 and is hook-type. Fixation of the tongue component 10 to the main component 1, is done by first affixing band 23 to band 24, followed by affixing band 22 over band 23. The bands of velcro are fixed to the brace component between the two layers of the hard shell 2.

[0040] FIG. 4 shows the brace in its most flexion-restraining position with the tongue 10 fully pulled in towards the main component 1. The angle of full extension of the hock joint varies between dogs of different breeds and between individual dogs of the same breed. This variability can be accommodated by the length of the straps and the angle of the bend of the tongue 10. It is also possible to modulate the restraint on the hock joint range of flexion/extension by bending the tongue 10 into the shape shown schematically by dashed line 10a. The straps 20 can be lengthened as shown by 20a. This now allows for an increased range of hock joint flexion/extension movement by about 5 to 10 degrees and may be desired in the course of the joint immobilization during typically 10 to 16 weeks, most commonly about 12 weeks. The position of the brace shown is typical for the mid-stance of the gait. The pad 13 contacts the ground through most of the stance phase, protecting the main component 1 of the brace from wear and tear and also reducing the impact loading that would result from the hard shell hitting the ground.

[0041] FIG. 5 shows orthogonal views of the hard shell component 2 of the brace without internal padding. For the hard shell components, preferably a thermoplastic material, most preferably a composite of wood and a bio-degradable polymer, e.g. Woodcast (Onbone Oy, Finland) is used. This makes it possible to fine-tune the hard shells to the individual anatomical features by heating the brace to an elevated temperature, e.g., of about 65 C., and bending the shells into the desired shape. Shell 2 and the tongue 10 may be formed from multiple layers of material, e.g., Woodcast, to provide the stiffness and the strength needed. Two layers of 2 mm in thickness each with the overlap along the midline of the brace are usually sufficient. Velcro strips 30 and 31 of the hook-type are glued to the inner side of the shell 2 to provide anchoring for the padding 6 made from preferably neoprene foam. Flanged nuts 16 at the distal end of the shell accept screws 14 for affixing of rubber pad 13.

[0042] FIG. 6 shows the distal end of the brace with exchangeable rubber pads 13 affixed to the shell 2 by two screws 14. The pads are made in several lengths from the tip of the pad to the fixation screws, shown here as 13a and 13b. Selection of the appropriate pad allows for sharing of the ground reaction between the brace and the paw. The pad also protects shell 2 from wear and tear against the ground and softens the contact impact on hard surfaces. Metal washers 15 are inserted at the bottom of the screw head recesses to allow for proper screw tightening into flanged nuts 16.

[0043] Alternative, a commonly used material for hard orthoses is polypropylene, which requires a much higher temperature for molding.

[0044] Having disclosed at least one embodiment of the present invention, variations will be understood by one of ordinary skill in the art. Such adaptations, modifications, and improvements are considered part of the invention.