Intrathecal excision of a calcaneal osteochondroma within the tarsal sheath in a 2‐year‐old thoroughbred colt

Summary Reports of osteochondromas in areas other than the caudal distal radial metaphysis are limited in the literature. Osteochondromas near tendinous structures and their associated synovial sheaths can result in lameness from tendonitis and tenosynovitis caused by protrusion and impingement. Computed tomography (CT) imaging provides detailed and comprehensive documentation of bone and soft tissue pathology accompanying osteochondromas in atypical and intricate anatomical locations. Accurate preoperative assessment improves surgical planning, prognostication and case outcome. Surgical resection is typically curative, and pending the extent of associated soft tissue damage, horses that undergo surgical management carry an excellent prognosis to return to athletic function. Tenoscopic surgery enhances the evaluation and debridement of tendinous structures while maintaining small incisions, which in this highly mobile area is optimal for healing compared to an open approach. This report details the diagnostic assessment, intrathecal resection and outcome of a horse with an osteochondroma emanating from the calcaneus.