An assessment of the intelligent knee prosthesis

Address for correspondence: Stephen Kirker, Disablement Services Centre, Addenbrooke’s Hospital NHS Trust, Cambridge CB2 2QQ, UK. Objectives: To compare gait symmetry, energy expenditure and subjective impressions of transfemoral amputees walking with a standard pneumatic swing-phase control knee and a new type of prosthetic knee. Design: Open crossover study of six users while walking on a treadmill at self-selected slow and fast speeds, and postal questionnaire survey. Setting: Disablement services centre in a teaching hospital. Subjects: Fourteen transfemoral amputees who had been using the intelligent knee prosthesis for more than three months. Main outcome measures: Difference in step length of prosthetic and natural leg as percentage of stride length, oxygen consumption and subjective effort of walking with each type of prosthesis. Results: Gait was more symmetrical with the intelligent knee prosthesis (1 % versus 5% slow, 1 % versus 3% fast, p < 0.05) but oxygen consumption did not differ between prostheses. Users reported less subjective effort walking at normal and fast speeds, outdoors and down slopes and expressed a strong preference for the new prosthesis. Conclusions: Transfemoral amputees’ gait is symmetrical at fast and slow