To evaluate the radiological and clinical results including the patient's satisfaction after total knee arthroplasty (TKA) using two differently designed system for both knees in the same patient.

From January 2002 to January 2003, thirty-two bilateral TKAs were prospectively performed using two differently designed systems. One side TKA was performed using a mobile bearing (PFC RP, Dupey) system, and the other side was performed using a fixed bearing system (PFC, Dupey). All 32 patients were followed up for an average of 51.4 months. The mean age of the study group was 67 years (range 54-75). The clinical results were evaluated from the Knee Score, WOMAC score for the patient's satisfaction and range of motion. Radiological analysis including the tibiofemoral angle was also carried out. An independent T-test was used for statistical analysis.

The preoperative average knee score improved to 87.3 from 42.5 in the mobile bearing group and to 86 from 39 in the fixed bearing group respectively. The preoperative average WOMAC score decreased to 11.2 from 84.9 in the mobile bearing group and to 16 from 85.5 in the fixed bearing group. The average preoperative range of knee motion improved to 114.5° from 104.5° in the mobile bearing group and to 113.8° from 104.7° in the fixed bearing group. The average preoperative tibiofemoral angle improved to 5.3° valgus form 4.5° varus in the mobile bearing group and to 6° valgus from 3.8° varus in the fixed bearing group. The only result statistically significant was the WOMAC score (p<0.05).

The two differently designed TKA system produce similar outcomes except for the subjective satisfaction in the mid-term clinical and radiological evaluation.