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

The C-Leg (R) (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-Lege with those wearing a common noncomputerized prosthesis, the Mauch SNS (R) (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-Lege group compared with the Mauch SNS (R) group (55.2 degrees +/- 6.5 degrees vs 64.41 degrees +/- 5.8 degrees, respectively; p = 0.005); the C-Leg (R) group was similar to control subjects' peak swing knee-flexion angle (56.0 degrees +/- 3.4 degrees). Stance knee-flexion moment increased for the C-Legs group compared with the Mauch SNS (R) 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 (R) group compared with the Mauch SNS (R) group (0.66 +/- 0.04 vs 0.70 +/- 0.06 in, respectively; p = 0.005), which resulted in increased symmetry between limbs for the C-Leg (R) group. Subjects also walked faster with the C-Leg (R) versus the Mauch SNS (R) (1.30 +/- 0.1 vs 1.21 +/- 0.1 m/s, respectively; p = 0.004). The C-Lee prosthetic limb vertical ground reaction force decreased compared with the Mauch SNS (R) (96.3 +/- 4.7 vs 100.3 +/- 7.5 % body weight, respectively; p = 0.0092).