135 LOTUS KNEE UNICOMPARTMENTAL ARTHROPLA STIES IN UNICOMPARTMENTAL ARTHROSIS - RESULTS AFTER 4.6 YEARS AVERAGE FOLLOW-UP

Controversy exists on the indications and results of unicompartmental arthroplasty in the treatment of unicompartmental knee arthritis. This led us to study 135 Lotus prostheses implanted from December 1974 to February 1990. The follow-up lower than 1 year for 14 knees (11 were l ost to follow-up, 3 were reoperated). One hundred and twenty-one knees were clinically evaluated with an average follow-up of 4 years and 6 months using both the GUEPAR and the Knee society grading systems. 71. 9 per cent of the knees were rated good, 28.1 per cent were rated poor (19 per cent were revised). This important rate of poor results was d ue to poor technique (11 knees) and to poor indications (7 knees). Pol yethylene wear, and radiolucent line especially when it was evolutive were significantly correlated to failures and poor results. Failures w ere seldom unifactorial but often multifactorial. Over or undercorrect ion of coronal deformity, absence or lengthening of the anterior cruci ate ligament were the failure factors most often found. Decrease of go od results with time, and polyethylene wear of unicompartmental arthro plasties are factors which lead us to carefully consider osteotomy for patients under 65 years. The failure rate may decrease with good indi cations and a better technique allowing unicompartmental arthroplasty to be a good choice for unicompartmental arthritis.