Physical function, gait and dynamic balance of transfemoral amputees using two mechanical passive prosthetic knee devices

Objective: To investigate the effect of the 3R90 and 3R92 (Otto Bock Healthcare) mechanical passive prosthetic knee devices on the physical function, gait, and dynamic balance (sudden stop and turn) of transfemoral amputees. Design: Intervention study with crossover design. Setting: University research center. Participants: Men (N=5; mean age +/- SD, 58.8 +/- 11.9y) with unilateral transfemoral amputation. Intervention: Prosthetic knee joints (N=2: 3R90 and 3R92). Acclimatization ranged from 14 to 47 days (25.5 +/- 9.3d). Main Outcome Measures: Physical function, gait, dynamic balance. Results: The Timed Up and Go Test, 6-Minute Walk Test, and Four Square Step Test measures improved with the 3R92. Total scores on the Prosthesis Evaluation Questionnaire were similar for the 3R92 (82.0 +/- 6.3) and the participant's own or original device (83.9 +/- 4.8). These devices were rated higher than the 3R90 (65.5 +/- 16.8). Compared with the original device, gait velocity was significantly slower (5cm/s: P=.017) with the 3R92, but was unchanged for the 3R90. This difference was not considered clinically significant because the effect size was small (0.2). No other significant gait differences were found. Large temporal gait asymmetries observed with the original device remained with the 3R90 and 3R92 (step, approximate to 20%; single support, approximate to 30%; stance, approximate to 19%). Although no significant differences were found for the sudden-turn or sudden-stop tasks, the sudden-turn group success rates were highest with the original devices.