Arthrodesis In Horses

Equine Arthritis

• Bone spavin is a degenerative joint disease or arthritis of the hock. It's the most common cause of equine stiffness and lameness, and generally seen in sport or performance horses. The majority of medical management techniques used to treat arthritis of the lower hock joints result in only temporary improvement of pain and use of the affected limb. It typically produces longer recovery times, as well as progressive joint deterioration. Nearly 50 percent of horses treated using conventional equine arthritic methods remain lame.

Joint Fusion

• A case-by-case protocol must be used in determining successfully candidates for joint fusion or arthrodesis. Although multiple joints may be fused successfully, not all joints are necessarily responsive to the procedure. Joint fusion is achieved by effectively destroying the cartilage between the joints and allowing the bones to fuse together. Although horses may experience severe, short-term pain following the procedure, arthrodesis typically eliminates the arthritic pain and resulting lameness issues. Long-term prognosis fluctuates among horses.

Surgical Arthrodesis

• Surgical arthrodesis involves destroying the articular cartilage surrounding the joint using a laser or surgical drill, and applying a bone plate or placing a bone graft between the joints. The joints are aligned into a stable, weight-bearing position and screws are placed in various positions depending upon the individual joint. Surgical arthrodesis results in joint fusion by removing the cartilage and allowing the bones to fuse together.

Chemical Arthrodesis

• Destruction of the cartilage between the hock joint may be performed by injecting a chemical, called monoiodoacetate (MIA), which erodes the surface of the joint and results in the bones fusing together. Chemical arthrodesis is an alternative to more invasive surgery and has shown evidence of improvement of the joint, however, it produces significant short-term pain and the degree to which it results in long-term arthritic improvement and soundness varies. According to Chris Bell, DVM of the American Association of Equine Practitioners (AAEP), "Historical attempts to fuse these small joints using mono-iodoacetate resulted in severe soft tissue damage, progression of arthritis in more proximal (higher up) hock joints, and persistent pain."

Ethyl Alcohol Arthrodesis

• Arthrodesis through ethyl alcohol injection to the joint doesn't produce a considerable amount of pain, as do the other methods. A study conducted by the Western College of Veterinary Medicine, in Alberta, Canada, revealed ethyl alcohol injections produce minimal pain and no lameness in horses. The use of ethyl alcohol as an alternative to chemical arthrodesis has been shown to effectively destroy the joint's cartilage, while successfully fusing the joints together and with a limited amount of pain or complications. Horses suffering from significant osteoarthritis of their lower hock joints that hasn't responded to conventional arthritic medical treatments, or young horses with juvenile arthritis, are possible candidates for ethyl alcohol arthrodesis. However, Chris Bell says this method of joint fusion is not recommended for horses experiencing mild to moderate osteoarthritis and that a full veterinary exam should be completed before considering its use.