ROLFE M. RADCLIFFE, DVM, Diplomate ACVS, JON CHEETHAM, Vet MB, Diplomate ACVS, ABRAHAM J. BEZUIDENHOUT, BVSc, DVSc, NORM G. DUCHARME, DVM, MS, Diplomate ACVS, and ALAN J. NIXON, BVSC, MS, Diplomate ACVS Veterinary Surgery December 2008 37 8 733 - 740 Objective—To describe anatomic considerations and arthroscopic technique in horses for arthroscopic removal of palmar/plantar osteochondral fragments from the proximal interphalangeal (PIP) joint. Study Design—Retrospective study. Animals—Adult horses (n=4) with osteochondral fragments of the palmar/plantar PIP joint. Methods—Arthroscopic removal of palmar/plantar osteochondral fragments within the PIP joint was performed with horses in dorsal recumbency under general anesthesia. Medical records of affected horses were reviewed to determine history; physical, lameness, and radiological findings; surgical technique; complications and outcome. Results—Two horses had lameness localized to the PIP joint. Two other horses had lameness suspected, but not confirmed to the pastern region. One of these horses had a history of intermittent lameness, but was not lame on admission. All horses had radiographic evidence of palmar/plantar osteochondral fragmentation within the PIP joint. Fragmentation was located abaxially in 2 horses in the hind limb and axially in 2 horses in the left forelimb. Osteochondral fragments were successfully removed via a palmar/plantar arthroscopic approach in all horses. Three horses returned to previous levels of athletic performance; 1 horse was used for trail riding instead of reining. Conclusions—Arthroscopy of the palmar/plantar pouch of the PIP joint allowed limited assessment of the joint and removal of osteochondral fragments. Clinical Relevance—Arthroscopy of the palmar/plantar PIP joint pouch for assessment and removal of osteochondral fragments is possible and should be considered when lameness is localized to this joint.