Comparison Between the C-leg® Microprocessor-Controlled Prosthetic Knee and Non-Microprocessor Control Prosthetic Knees: A Preliminary Study of Energy Expenditure, Obstacle Course Performance, and Quality of Life Survey

This study investigated energy expenditure and obstacle course negotiation between the C-leg® and various non-microprocessor control (NMC) prosthetic knees and compared a quality of life survey (SF-36v2™) of use of the C-leg® to national norms. Thirteen subjects with unilateral limb loss (12 with trans-femoral and one with a knee disarticulation amputation) participated in the study. The mean age was 46 years, range 30 – 75. Energy expenditure using both the NMC and C-leg® prostheses was measured at self-selected typical and fast walking paces on a motorized treadmill. Subjects were also asked to walk through a standardized walking obstacle course carrying a 4.5 kg (10 lb) basket and with hands free. Finally, the SF-36v2™ was completed for subjects while using the C-leg®. Statistically significant differences were found in oxygen consumption between prostheses at both typical and fast paces with the C-leg® showing decreased values. Use of the C-leg® resulted in a statistically significant decrease in the number of steps and time to complete the obstacle course. Scores on a quality of life index for subjects using the C-leg® were above the mean for norms for limitation in the use of an arm or leg, equal to the mean for the general United States population for the physical component score and were above this mean for the mental component score. Based on oxygen consumption and obstacle course findings, the C-leg® when compared to the NMC prostheses may provide increased functional mobility and ease of performance in the home and community environment. Questionnaire results suggest a minimal quality of life impairment when using a C-leg® for this cohort of individuals with amputation.