History of chronic right front limb lameness was diagnosed prior to January 2010 in a 19 year old neutered male Zalophus californianus. The right carpus was consistently swollen and warm. Radiographs of the right carpus revealed variable osteolysis of the osseous structures of the radio-carpal, intercarpal and carpometacarpal joints with collapse of the joint spaces and instability. Treatment regimens included various antibiotics and analgesics with no resolution. The animal also had bilateral cataracts with OD anterior lens luxation, which prompted surgical attention. Bilateral cataract extraction and an exploratory arthrotomy of the right carpus were performed concurrently. Arthrotomy of the radiocarpal/intercarpal and carpometacarpal joints was performed and devitalized bone in each joint debrided. Samples of synovial membrane, synovial fluid and bone were submitted for culture/sensitivity and histopathologic evaluation. A pneumatic tourniquet was secured to the distal radius and an intraosseous catheter placed into the radius distal to the tourniquet. Once secured, 1 gram of amikacin was infused into the radius and the tourniquet left in place for 45 minutes to complete a regional limb perfusion while the carpus was debrided and liberally flushed. Bone morphogenetic protein (BMP-6)-soaked collagen sponges were packed into each joint space to promote osteogenesis to increase stability. The joints were closed routinely in three layers. Biopsies of bone and synovial membrane revealed widespread severe lymphocytic-plasmacytic inflammation of the synovium and subsynovial connective tissue. No bacteria or fungi were noted with special stains. All cultures were negative for bacterial growth. The patient recovered well from the carpal surgery, there was primary healing of all incisions and sequential radiographs revealed improving bone density, stability and no further osteolysis. Clinically the patient is doing well, lameness is resolved, and sea lion is back on exhibit.