PHYSIOLOGICAL RESPONSES OF MULTIPLE SPEED TREADMILL WALKING FOR SYME VERSUS TRANSTIBIAL AMPUTATION

PURPOSE: Motor function and wound healing are important considerations when determining the level of lower extremity amputation. The choice of trying to salvage the longest limb possible has been largely based on the premise that a longer limb will provide enhanced performance. However, the more distal site of amputation may result in decreased circulation and impaired wound healing. Research on this topic is limited. The purpose of this study was to compare the physiologic responses between syme and transtibial treadmill walking in a longitudinal single subject experimental design. SUBJECTS: The test subject was a 35-year-old male traumatic syme amputee who underwent elective transtibial amputation due to chronic stump skin break-down and unstable gait with syme prosthesis. Fifteen male non-amputees (age: 26 [+ or -] 4) served as control subjects. METHODS: Testing involved a self-selected walking velocity (SSWV) test and a continuous multiple speed treadmill test (53.64, 67.05, 80.46, 93.87 and 107.28 m/min) pre-transtibial (syme) and 16 months post-transtibial amputation. A standardized protocol (3 min. acclimation, 2 min. timed distance measurement of comfortable walking over a 44-foot corridor) was used for the SSWV test. The outcome variables included oxygen uptake, relative exercise intensity (percent of age-predicted maximum heart rate) and gait efficiency (oxygen uptake per meter traveled). Oxygen uptake was determined with a metabolic cart and heart rate by ECG radiotelemetry. ANALYSIS: Descriptive analysis included within subject (syme versus transtibial) and between subject (amputee versus non-amputee) percent difference calculations and graphical comparisons. RESULTS: Compared to syme amputation, transtibial amputation showed a range of 3%-10% lower oxygen consumption, 7%-11% lower relative exercise intensity, 3% - 10% improvement in gait efficiency for the five speeds and an 8% improvement in SSWV (74 to 80 m/min) which was comparable to reported non-amputee SSWV. CONCLUSIONS: Based on the results of this study, the principles governing the decision of optimal level of lower extremity amputation in orthopedic surgery may need to be reconsidered. ACKNOWLEDGMENTS: This research was partially supported by a grant from Flex-Foot Inc., Aliso Viego, CA, USA.
Lin S-J, Nielsen DH, Shurr DG, (*) Saltzman CL; Physical Therapy Graduate Program, (*) Department of Orthopedic Surgery, College of Medicine, University of Iowa, Iowa City, IA, [...]