[Clinical and radiologic evaluation of a polylactic acid interposition arthroplasty after trapezectomy]

Surgical management of trapeziometacarpal osteoarthritis does not obey to strict rules. The use of interposition implants made of different materials leads to enrichment of surgeon's resources. This prospective study reports the radiological and clinical results of 45 patients treated by total trapeziectomy with polylactic acid interposition implant, with an average follow-up of 31 months. Thirty-seven surgical treatments were carried out after ineffective medical treatment. According to Dell classification, there were five stages II, 30 stages III and two stages IV. Mean age was 66 years. Dominant side was involved in 60%. Thumbs were pain free at 5 months in average and 81% of the patients reported good results (Alnot stages 0 and 1). The average opposition was 9.1/10, the average M1M2 angle was 40°, and the average key pinch strength was 4.4 kg. Six patients suffered from sympathetic dystrophy but neither infection nor local inflammatory reaction was observed. Collapse of the trapezium space was constant and the trapezium space ratio was 76% at the follow-up. Seventy-five per cent of patients returned back to their occupation. The satisfaction rate was 89%. The radioclinical results were very good in our series. The interposition of polylactic acid implant permits to avoid the presumed complications of tendon harvesting, and those of other types of material used in the same indication. Its safety seems excellent.