Magnitude and variability of loading on the osseointegrated implant of transfemoral amputees during walking

Lee, Winson C.C.; Frossard, Laurent A.; Hagberg, Kerstin; Haggstrom, Eva; Gow, David Lee; Gray, Steven; Brånemark, Rickard

doi:10.1016/j.medengphy.2007.09.003

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Volume 30, Issue 7 , Pages 825-833, September 2008

Magnitude and variability of loading on the osseointegrated implant of transfemoral amputees during walking

Winson C.C. Lee
- School of Engineering Systems, Queensland University of Technology, Brisbane, Australia
- Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
- Corresponding author at: Institute of Health & Biomedical Innovation, Queensland University of Technology, Victoria Park Road, Kelvin Grove, Qld 4059, Australia. Tel.: +61 7 3138 6099; fax: +61 7 3138 6030.
Laurent A. Frossard
- School of Engineering Systems, Queensland University of Technology, Brisbane, Australia
- Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
Kerstin Hagberg
- Centre of Orthopaedic Osseointegration, Sahlgrenska University Hospital, Goteborg, Sweden
Eva Haggstrom
- Department of Prosthetics and Orthotics, Sahlgrenska University Hospital, Goteborg, Sweden
David Lee Gow
- Caulfield General Medical Centre, Melbourne, Australia
Steven Gray
- Plastic & Reconstructive Surgery Unit/Osseointegration-OPRA Programme, The Alfred Hospital Melbourne, Australia
Rickard Brånemark
- Centre of Orthopaedic Osseointegration, Sahlgrenska University Hospital, Goteborg, Sweden

Received 7 February 2007; received in revised form 24 September 2007; accepted 24 September 2007. published online 02 November 2007.

Abstract

This study directly measured the load acting on the abutment of the osseointegrated implant system of transfemoral amputees during level walking, and studied the variability of the load within and among amputees. Twelve active transfemoral amputees (age: 54±12 years, mass: 84.3±16.3kg, height: 17.8±0.10m) fitted with an osseointegrated implant for over 1 year participated in the study. The load applied on the abutment was measured during unimpeded, level walking in a straight line using a commercial six-channel transducer mounted between the abutment and the prosthetic knee. The pattern and the magnitude of the three-dimensional forces and moments were revealed. Results showed a low step-to-step variability of each subject, but a high subject-to-subject variability in local extrema of body-weight normalized forces and moments and impulse data. The high subject-to-subject variability suggests that the mechanical design of the implant system should be customized for each individual, or that a fit-all design should take into consideration the highest values of load within a broad range of amputees. It also suggests specific loading regime in rehabilitation training are necessary for a given subject. Thus the loading magnitude and variability demonstrated should be useful in designing an osseointegrated implant system better able to resist mechanical failure and in refining the rehabilitation protocol.