Twenty-two patients with Wilson's disease were evaluated for arthropathy with history, examination, and radiographs. Knee arthroscopy with cartilage and synovial biopsies was performed in 4 patients. Radiologic findings were minimal, including osteophytes, subchondral cysts, and joint space narrowing. Chondrocalcinosis was observed in 3 patients. Cartilage and synovial biopsies studied by energy dispersive elemental analysis showed copper and sulfur diffusely throughout cartilage in 2 of 4 patients. No crystals were found. The finding of copper in cartilage biopsies suggests that copper deposition may be a factor in the etiology of arthropathy, although definitive studies remain to be performed.