Silastic sheet interposition arthroplasty was performed in 20 patients with persistently painful but stable wrists. Synovial recurrence with progression of symptoms was seen in one patient. Quantitative analysis of pain demonstrated an 87% improvement in their perception of pain in the remaining 19 patients, with an average follow-up of 8.5 years. The postoperative range of motion was 58 degrees Total Active range of Motion (TAM) (range 27 degrees - 97 degrees). Nine patients showed later ulnar translocation of the carpus, and 10 patients had continuing carpal collapse. There was no relation between these changes and the degree of pain relief at the radio-carpal joint. Those patients operated on within 18 months of the onset of symptoms showed a significantly greater post-operative range of motion (68 degrees) compared to those whose symptoms had persisted from 2 to 4 years (48 degrees).