The long-term outcome of silastic implant arthroplasty of the first metatarsophalangeal joint: a retrospective analysis of one hundred and eight feet.

PURPOSE: The short-term results of silastic implant of the first metatarsophalangeal joint (MTPJ) have been successful. However, reservations exist regarding long-term results. The aim of this study was to evaluate long-term outcome of silastic implant prosthesis in treatment of hallus rigidus.

METHODS: This was a retrospective study, with 108 feet in 83 patients, operated upon between 1988 and 2003. Mean age at operation was 55 years (SD 8.1) with a follow-up period of 8.5 years. Outcome measures included the American Orthopaedic Foot and Ankle Scoring system(AOFAS), passive and active arc of motion. Patients' satisfaction was assessed using the visual analogue scale. All the patients had anteroposterior and oblique views and were assessed for loosening and osteolysis. Pedobarographic studies were performed using the Musgrave Footprint. Complications and revisions were recorded.

RESULTS: The mean total AOFAS score was 77.5 (SD 13.4). Mean active and passive arc of motions were 36.8 degrees (SD 19.13) and 46.82 degrees (SD 17.19), respectively. Patient satisfaction showed mean VAS of 7.73 (SD 2.41). Prostheses were removed in three feet at three, five and seven years respectively because of persistent pain. Radiologically 25 feet (23 %) had osteolysis but were non progressive and didn't correlate with the functional outcome.

CONCLUSION: We can conclude that silastic implant arthroplasty is an effective procedure in hallux rigidus management with satisfactory functional outcome and high patient satisfaction.