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.ObjectiveTo quantify the energy efficiency of locomotion and free-living physical activity energy expenditure of transfemoral amputees using a mechanical and microprocessor-controlled prosthetic knee.DesignRepeated-measures design to evaluate comparative functional outcomes.SettingExercise physiology laboratory and community free-living environment.ParticipantsSubjects (N=15; 12 men, 3 women; age, 42±9y; range, 26–57y) with transfemoral amputation.InterventionResearch 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 MeasuresObjective measurements of energy efficiency and total daily energy expenditure were obtained. The Prosthetic Evaluation Questionnaire was used to gather subjective feedback from the participants.ResultsSubjects 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).ConclusionsPeople 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.