149. OUTCOMES IN A SERIES OF 54 LATERAL UNICOMPARTMENTAL KNEE PROSTHESES AT EIGHT YEARS FOLLOW-UP

Abstract

Purpose of the study: The purpose of this study was to report the results observed in a consecutive series of 54 lateral unicompartmental knee prostheses with minimum five years follow-up.

Material and methods: One hundred forty-four unicompartmental cemented HLS resurfacing prostheses were implanted with a chromium-cobalt femoral element and an all polyethylene polyethylene element. Among these consecutive implantations performed from 1998 to 2003 in accordance with indications established in 1988, 54 were lateral unicompartmental knee prostheses (37.5%) implanted in 10 men and 44 women. Mean age was 68.5 years (range 25–88). A lateral approach was used for the first six implants in this series. One patient was lost to follow-up, five died and one underwent revision for a total prosthesis. Forty-seven patients were reviewed with mean 100.9 months follow-up (64–159). Clinical data were analysed with the IKS criteria and all patients had a complete radiographic work-up before surgery and at last follow-up.

Results: In this series 96.3% of patients (n=52) were satisfied or very satisfied. Mean flexion was 133 (110–150). The mean knee score was 81.1 (25–100). Mean residual alignment was 2° valgus. A lucency was noted in 13.2% of knees, but remained stable. There was one failure requiring revision for a total prosthesis (loosening of the tibial component). The Kaplan-Meier survival was 98.1% at ten years. Three patients exhibited wear of the medial femorotibial compartment and had a medial unicompartmental implant. The overall survival (rein-tervention irrespective of reason) was 91.1%.

Discussion: Outcomes were very satisfactory, globally similar to recent series in the literature. Reliable sustainable outcomes with lateral unicompartmental implants have led us to widen our indications (moderate overweight, younger patients).