Energy cost of walking: Comparison of ''Intelligent prosthesis'' with conventional mechanism

Objective: To determine physiological energy cost with Blatchford's ''Intelligent Prosthesis'' (IF) compared to energy cost with a conventional pnuematic swing phase control (PSPC) mechanism. Design: Before-After trial: subjects fitted with TP walked on programmable treadmill at speeds: 6min slow, 6min fast, 8min while speed changed, between slow, normal, and fast, every minute, and 6min normal. Breath-by-breath analysis of subject's expired air determined average Vo(2) (L/min) within each period. Procedure repeated after 1-week interval using PSPC prosthesis. Testing sessions supervised by experienced prosthetist. Setting: Rehabilitation centre. Subjects: Volunteer sample. Three men, unilateral transfemoral traumatic amputee patients, ages 39 to 59 years. Normally used ischial containment socket, Blatchford Endolite Stabilised Stance Flex knee with PSPC and Multiflex foot and ankle. Interventions: Fitting, programming, and alignment of IP (own socket) by Bioengineering Unit's resident prosthetist. IP's microprocessor programmed to facilitate five walking speeds. Main Outcome Measure: Physiological energy cost (Vo(2)), of using LP compared to using PSPC mechanism. Results: Two subjects displayed reduced Vo(2) of between 5.6% and 9.0% using IP compared to PSPC prosthesis at a pace either faster or slower than their normal pace. Third subject showed no significant change in oxygen consumption despite IP unit being heavier. All subjects displayed reduced Vo(2) (aver aging 4.1%) using IP for period of variable speed walking. Conclusions: Although differences were small, they tend to indicate that use of the heavier IP unit lowered the energy cost of walking at speeds other than the amputee's normal pace. (C) 1997 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.