Courtesy of Dr. Matthew T. Brokken.
Radiocarpal and/or middle carpal osteoarthritis typically appears with chronic thickening of the joint capsule and usually associated decreased range of motion. Radiographic changes develop slowly, and usually the degree of articular cartilage compromise is severe. Cases that can possibly lead to osteoarthritis should be treated aggressively and correctly. Treatment of severe osteoarthritis is largely palliative. Osteoarthritis of the carpometacarpal joint has been described mainly in Arabian and Quarter horses. This condition typically affects the medial aspect of the joint and is characterized by lameness (minimal at first), firm swelling over the medial aspect of the distal carpus, and response to intra-articular analgesia of the middle carpal joint. Radiographs typically show periarticular new bone proliferation (sometimes marked) over the proximal second and/or third metacarpal bone, lysis and/or sclerosis of the bones surrounding the medial carpometacarpal joint, and possible loss of the medial joint space. Treatment consists of conservative therapy (systemic and/or intra-articular anti-inflammatories) and possible facilitated arthrodesis with use of passage of drill bits across the joint. ( See also page Osteoarthritis of the Shoulder in Horses.)
