Physiologic Range of Step-by-step Variations in Lower Limb Prosthesis Forces During Walking

Physiologic Range of Step-by-step Variations in Lower Limb Prosthesis Forces

In human gait there is a certain amount of variation between steps; some considered physiological and owed to variations in environment or posture, and some severe enough to be indicative of gait instabilities that may lead to stumbling and falling. In users of lower limb prosthetics, such gait instabilities are of especially great interest.

The study investigates the correlation between socket alignment quality and gait step-by-step variability in users of trans-tibial-prosthetics. It is hypothesized that a clearly defined range of step-by-step variability exists, and that therefore step-by-step variability is suitable as an outcome variable for the assessment of socket alignment.

A sample of ten persons with trans-tibial amputation will be recruited for this pilot study. Subjects will be asked to walk on different natural surfaces while the socket alignment is successively perturbed. Step-by-step variations in horizontal ground reaction forces and torsional moments will be measured and statistically compared.

Inclusion Criteria:

• activity classification of K2 to K4
• experience in prosthesis use of at least one year
• stated ability to walk pain free for at least 30 minutes

Exclusion Criteria:

• age of less than 18 years
• acute or ongoing residual limb pain
• use of a prosthesis that is not suitable for installation of the load cell (e.g. is too short, or has non-removable cosmesis)