LATERAL UNICOMPARTMENTAL ARTHROPLASTY: 54 CASES WITH MINIMUM FIVE YEARS FOLLOW-UP

Abstract

Recently in Europe, Unicompartmental Knee Arthroplasty (UKA) has regained interest in the orthopedic community; however, based on various reports, results concerning UKA for isolated lateral compartment arthritis seemed to be not as good as for medial side. In 1988 our department started using Unicondylar Knee Pros-thesis with a fixed all polyethylene bearing tibial component and resurfacing of the distal femoral condyle. The aim of this study is to report on our personal experience using this type of implant for lateral osteoarthritis with a long follow-up period.

Between January 1988 and October 2003, we performed 54 lateral UKAs (52 patients) and all were implanted for lateral osteoarthritis (3 cases of which were posttraumatic). 52 knees in 50 patients were available after a minimum duration of follow-up of five years (96.3 %). The mean age of the patients at the time of the index procedure was 72.2±1.5 years. The mean duration of follow-up was 100.9 months (range 64 – 189 months).

At follow up, 4 underwent a second surgery: one conversion to TKA for tibial tray loosening at 2 years and 3 revisions for UKA in the medial compartment. No revision surgery was necessary for wear of either of the two components, nor for infection. The mean IKS knee score was 94.9 points, with mean range of motion 132.6° (range, 115–150) and a mean IKS function score totaling 81.8 points. The average femorotibial alignment was 1.8° (range −6° to 12°). Radiolucent lines in relation to the tibial component were appreciated in 6 knees and to the femoral component in 1 knee. Implant survival was 98.08% at ten years.

The UKA with a fixed bearing tibial component and a femoral resurfacing implant is a reliable option for management of isolated lateral knee osteoarthritis. It offers excellent medium-term results for both functional level and implant survival which even currently enable us to widen our selection criteria to include younger patients or those associated with starting patellofemoral osteoarthritis.