Impact of modern technique on long-term results of total condylar knee arthroplasty.

Abstract

This study reports the 14-year survivorship for 106 consecutive total condylar knee arthroplasties implanted using modern technique. All were performed by a single surgeon and have been observed prospectively since 1979. Failure was defined as revision for any reason, or radiographic evidence of loosening of the components. Life-table analysis reveals a 95.6% clinical survival rate at 14 years, with no radiographically loose components. Confidence interval is +/- 4.2%. There were 4 revisions, but none for aseptic loosening, and there are no impending revisions. Thirty-seven patients (49 knees) were known to be deceased as of April 1993, and 8 other patients are lost to followup. Clinical results for patients with pre- and postoperative Hospital For Special Surgery knee scores show 72 knees rated excellent and 11 good (mean score, 90 points). The 4 failures were rated poor. Mean flexion was 100 degrees. Radiographs of 93 knees were evaluated using the criteria of the Knee Society. Average overall alignment was 5 degrees valgus. Radiolucencies were present in 29 of 78 femoral components with adequate radiographs, and averaged 1 mm in 1 zone. Tibial radiolucency was present in 42 of 93 tibiae, again averaging 1 mm in 1 zone, with no loose pegs. In comparison with the first series of total condylar prostheses, this series showed comparable clinical results, with improved radiographic results, and no radiographic failures.