Energy Expenditure and Activity of Transfemoral Amputees Using Mechanical and Microprocessor-Controlled Prosthetic Knees

Kaufman KR, Levine JA, Brey RH, McCrady SK, Padgett DJ, Joyner MJ. Energy expenditure and activity of transfemoral amputees using mechanical and microprocessor-controlled prosthetic knees. Objective: To quantify the energy efficiency of locomotion and free-living physical activity energy expenditure of transfemoral amputees using a mechanical and microprocessor-controlled prosthetic knee. Design: Repeated-measures design to evaluate comparative functional outcomes. Setting: Exercise physiology laboratory and community free-living environment. Participants: Subjects (N=15; 12 men, 3 women; age, 42±9y; range, 26-57y) with transfemoral amputation. Intervention: Research participants were long-term users of a mechanical prosthesis (20±10y as an amputee; range, 3-36y). They were fitted with a microprocessor-controlled knee prosthesis and allowed to acclimate (mean time, 18±8wk) before being retested. Main Outcome Measures: Objective measurements of energy efficiency and total daily energy expenditure were obtained. The Prosthetic Evaluation Questionnaire was used to gather subjective feedback from the participants. Results: Subjects demonstrated significantly increased physical activity-related energy expenditure levels in the participant's free-living environment (P=.04) after wearing the microprocessor-controlled prosthetic knee joint. There was no significant difference in the energy efficiency of walking (P=.34). When using the microprocessor-controlled knee, the subjects expressed increased satisfaction in their daily lives (P=.02). Conclusions: People ambulating with a microprocessor-controlled knee significantly increased their physical activity during daily life, outside the laboratory setting, and expressed an increased quality of life.