Effect of Prosthetic Foot on Residuum-Socket Interface Pressure and Gait Characteristics in an Otherwise Healthy Man With Transtibial Osteomyoplastic Amputation

Mai, Anh MSc; Commuri, Sesh PhD; Dionne, Carol P. PT, DPT, PhD, OCS, Cert MDT; Day, Jonathan CPO; Ertl, William J.J. MD; Regens, James L. PhD

JPO Journal of Prosthetics & Orthotics: October 2012 - Volume 24 - Issue 4 - p 211–220
doi: 10.1097/JPO.0b013e31826fdaf8
Case Report

ABSTRACT: This article elucidates the effect of prosthetic foot on the residuum-socket interface (RSI) pressure and gait characteristics in a man with transtibial osteomyoplastic amputation (TOA). The study evaluates the effect of three prosthetic feet, including 1) Renegade Foot® from Freedom Innovations (Irvine, CA), 2) Venture Foot™ from College Park (Fraser, MI), and 3) Proprio Foot® from Össur (Reykjavik, Iceland) in six gait activities: walking forward at “normal” pace, walking forward at fast pace, ascending and descending a staircase, and ascending and descending a ramp. Force resistive sensors were placed at six locations, including distal anterior end-bearing, middle posterior, and four proximal points inside the prosthetic socket, to capture real-time RSI pressures. Whereas nominal values of pressure were observed in the proximal region, greater pressure was observed at the distal anterior end-bearing region of the socket, which confirmed one of the intended outcomes of the TOA procedure. Of 36 statistical tests (t-test, p < 0.05), 35 tests (97.2%) confirmed the hypothesis that when the same prosthetic foot was used in the same gait activity, peak and mean pressures are greater at the distal anterior end-bearing location than at other locations. Furthermore, 182 of 216 (84.2%) statistical tests (t-test, significance level of 0.05) supported the hypothesis that at the same measured location during the same gait activity, different prosthetic feet result in different peak (or mean) RSI pressures. Coefficients of variation of the mean sustained pressures showed that when the gait activity was changed, each prosthetic foot affected the sustained pressure differently, even at the same measured location. Each prosthetic foot also had a direct effect on temporal gait parameters such as stance phase and gait cycle durations. These results elucidate the importance for clinicians to understand the characteristics of different prosthetic foot designs to match with the specific needs of the client with amputation.

This paper provides evidence that the choice of prosthetic foot impacts pressure distributions inside the socket during six gait activities using three different prosthetic feet for an amputee who underwent transtibial osteomyoplastic amputation (TOA) procedure. These results indicate that for the same socket design, loading characteristics inside the socket depend on the selected gait in combination with the type of prosthetic foot used, thus providing preliminary evidence that prosthetic foot design modifies the loading response inside the socket and potentially impacts the user’s comfort during selected walking activities.

ANH MAI, MSc, is affiliated with the School of Electrical and Computer Engineering, University of Oklahoma, Norman. SESH COMMURI, PhD, is affiliated with the Journal of Intelligent and Robotic Systems and the School of Electrical and Computer Engineering, University of Oklahoma, Norman. CAROL P. DIONNE, PT, DPT, PhD, OCS, CERT MDT, is affiliated with Mechanical Therapy Research Laboratory, The University of Oklahoma Health Sciences Center, College of Allied Health, Department of Rehabilitation Sciences. JONATHAN DAY, CPO, is affiliated with Department of Orthopedic Surgery & Rehabilitation, University of Oklahoma Health Sciences Center. WILLIAM J.J. ERTL, MD, is affiliated with the Department of Orthopedics Surgery & Rehabilitation, College of Medicine, University of Oklahoma Health Sciences Center. JAMES L. REGENS, PhD, is affiliated with the Center for Biosecurity Research and College of Public Health, University of Oklahoma Health Sciences Center.

Disclosure: The authors declare no conflict of interest.

This research was supported in part by the Cross disciplinary research grant, College of Engineering at The University of Oklahoma.

Correspondence to: Sesh Commuri, PhD, School of Electrical and Computer Engineering, Devon Energy Hall, 110 W Boyd St, DEH 432, University of Oklahoma, Norman, OK 73019; e-mail: scommuri@ou.edu

© 2012 American Academy of Orthotists & Prosthetists