Of 32 patients with Kienböck's disease, 19 had lunate silicone implant replacements, and 13 had coiled palmaris longus tendon replacement. The carpal height was measured and osteoarthritic changes were noted in plain x-ray films before and after the operation. Follow-up periods ranged from 3 to 11 years, with an average of 6 years 4 months. In patients in the mild stages of the preoperative carpal collapse, both excisional arthroplasties had good clinical results. The x-ray films showed that a silicone implant played a more important role in preventing further carpal collapse than a palmaris longus tendon replacement in patients in the early carpal collapse stage. However, the clinical results of the silicone implant replacement were unsatisfactory because of the postoperative progression of osteoarthritic changes or subluxation of the prosthesis in the advanced stages of carpal collapse. The palmaris longus tendon replacement gave satisfactory results in four of seven patients with advanced carpal collapse. These results suggest that silicone implant replacement is indicated primarily in patients with the early stages of carpal collapse, and replacement of the palmaris longus tendon is rarely recommended in either the early or late stages of carpal collapse.