Northwestern University Feinberg School of Medicine

Northwestern University Prosthetics-Orthotics Center

A Quantitative Analysis of Transfemoral Prosthetic Alignment

Principal Investigator: Steven Gard, PhD 

Project Director: Sara Koehler, MS

Funded by: Department of Veterans Affairs Rehabilitation Research and Development, Grant Number A7115R

Status: Completed

PurposeSagittal-plane joint kinetics with speed-matched, able-body control data

The purpose of this project is to examine relationships between prosthetic alignment in transfemoral amputees and how they control their prosthetic knee. Prosthetic alignment is important to the successful rehabilitation of lower-limb amputees and is a deciding factor in whether the prosthetic limb will restore function, minimize gait deviations, and be comfortable for the user. To improve the process of transfemoral alignment and promote an objective basis for practice, researchers and clinicians must first acquire a better understanding of the relationship between variations in prosthetic alignment and the biomechanical response of the amputee. The purpose of this study is to evaluate how gait biomechanics of persons with unilateral, transfemoral amputations are altered in response to systematic changes in sagittal-plane alignment. Both linear translations of the prosthetic knee and rotations of the prosthetic foot will be investigated during straight, level walking. To measure the response of transfemoral amputees to variations in sagittal-plane alignment, researchers will collect kinematic and kinetic data using quantitative gait analysis; and also will acquire EMG data of hip musculature, intrasocket contact pressure, and energy expenditure measurements. This work will characterize the relationship between prosthetic misalignment and the functional response of transfemoral amputee gait, including biomechanical asymmetries, increased energy expenditure, and residual limb pain. The results of this study will provide an understanding of how transfemoral amputees control their prosthetic knee joint and may establish a more systematic approach to the process of clinical prosthetic alignment.

Related Presentations and Publications

Koehler S. (2009) "An Investigation of Shock-Absorbing Components in Persons with Unilateral Transfemoral Amputation." Midwest Chapter American Academy of Orthotists and Prosthetists (AAOP) 2009 Annual Fall Session, Hickory Hills, IL, November 7.

Koehler S, Lipschutz R, Stine R, Gard S. The effect of transfemoral prosthesis alignment perturbations on gait in 38th American Academy of Orthotists and Prosthetists Annual Meeting and Scientific Symposium. March 21-24, 2012. Atlanta GA.

Koehler, Sara Rebecca. (2012) "Neuromechanical Mechanisms of Prosthetic Knee Joint Control: Associations with Prosthetic Alignment", Doctoral Dissertation, Biomedical Engineering, Northwestern University.

Koehler SR, Dhaher YY, Hansen AH. (2014) Cross-validation of a portable, six-degree-of-freedom load cell for use in lower-limb prosthetics research. J Biomech, 47(6), 1542-1547. 

Koehler S, Lipschutz R and Gard SA. (2015, accepted for publication). The Biomechanical Response of Persons with Transfemoral Amputation to Variations in Prosthetic Knee Alignment during Level Walking. Journal of Rehabilitation Research & Development.