Kinematic and kinetic comparisons of transfemoral amputee gait using C-Leg® and Mauch SNS® prosthetic knees

Abstract

The C-Leg® (Otto Bock, Duderstadt, Germany) is a microprocessor- controlled prosthetic knee that may enhance amputee gait. This intrasubject randomized study compared the gait biomechanics of transfemoral amputees wearing the C-Leg® with those wearing a common noncomputerized prosthesis, the Mauch SNS® (Ossur, Reykjavik, Iceland). After subjects had a 3-month acclimation period with each prosthetic knee, typical gait biomechanical data were collected in a gait laboratory. At a controlled walking speed (CWS), peak swing phase knee-flexion angle decreased for the C-Leg® group compared with the Mauch SNS® group (55.2° ± 6.5° vs 64.41° ± 5.8°, respectively; p = 0.005); the C-Leg® group was similar to control subjects' peak swing knee-flexion angle (56.0° ± 3.4°). Stance knee-flexion moment increased for the C-Leg® group compared with the Mauch SNS® group (0.142 ± 0.05 vs 0.067 ± 0.07 N·m, respectively; p = 0.01), but remained significantly reduced compared with control subjects (0.477 ± 0.1 N·m). Prosthetic limb step length at CWS was less for the C-Leg® group compared with the Mauch SNS® group (0.66 ± 0.04 vs 0.70 ± 0.06 m, respectively; p = 0.005), which resulted in increased symmetry between limbs for the C-Leg® group. Subjects also walked faster with the C-Leg® versus the Mauch SNS® (1.30 ± 0.1 vs 1.21 ± 0.1 m/s, respectively; p = 0.004). The C-Leg® prosthetic limb vertical ground reaction force decreased compared with the Mauch SNS® (96.3 ± 4.7 vs 100.3 ± 7.5 % body weight, respectively; p = 0.0092).