Unicompartmental versus Total Knee Arthroplasty in the Same Patient

Purpose: To compare the clinical and radiographic results of unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) in the same patient, and to investigate patient preference and satisfaction. Materials and Methods: Among the 56 patients who underwent a UKA in one knee and a TKA in the opposite knee between January 2002 and December 2004, 51 patients were followed up. The average follow-up period was 4 years. Results: The average Knee Society Score (KSS) improved from 53.5 preoperatively to 90.7 at last follow-up in the UKA knee, and from 50.4 to 89.8 in the TKA knee. The mean range of knee motion also improved from 124.7˚ to 133.2˚ in the UKA knee, and from 122.5˚ to 127.1˚ in the TKA knee. The tibiofemoral angle changed from 0.3˚ of varus to 5.6˚ of valgus in the UKA knee, and from 2.4˚ of varus to 5.8˚ of valgus in the TKA knee. For patient preference, 23 patients (45%) preferred the UKA knee and 19 patients (37%) preferred the TKA knee. Most patients (42 patients, 82%) reported being ‘very satisfied' or ‘satisfied' with both knees. Conclusion: The clinical and radiographic results of both the UKA and the TKA in the same patient were satisfactory at the 4-year follow-up. The UKA knee had a slightly better range of knee motion, but there was essentially no difference between the UKA knee and the TKA knee.