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.

Study Overview

• Status: Completed
• Conditions: Trans-tibial Limb Loss
• Intervention / Treatment: Procedure: Prosthetic alignment perturbation

• Study Type: Interventional
• Enrollment (Actual): 12
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15206
      • Bakery Square MSPO labs

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Trans-tibial prosthesis users; prosthetic alignment perturbation	Procedure: Prosthetic alignment perturbation; Prosthetic ankle plantar-flexion will be modified in different degrees, devices (prosthetic components) will not be modified from baseline condition

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Step-by-step variability	Peak horizontal ground reaction force (Fx and Fy) as well as peak axial torsion moment (Mz) will be extracted for 10 consecutive intermediary steps for each testing condition. Total range in Newtons over the 10 step sample, as well as maximal difference between consecutive steps in Newtons and percent will be reported for statistical analysis.	2 hours

Collaborators and Investigators

• Sponsor: University of Pittsburgh
• Collaborators: American Orthotic and Prosthetic Association

Study record dates

Study Major Dates

• Study Start: September 1, 2014
• Primary Completion (Actual): August 1, 2015
• Study Completion (Actual): November 1, 2015

Study Registration Dates

• First Submitted: August 28, 2014
• First Submitted That Met QC Criteria: September 4, 2014
• First Posted (Estimate): September 9, 2014

Study Record Updates

• Last Update Posted (Estimate): December 4, 2015
• Last Update Submitted That Met QC Criteria: December 3, 2015
• Last Verified: December 1, 2015

More Information

Terms related to this study

• Keywords: prosthetics; amputation; gait stability; step variability; load cell
• Other Study ID Numbers: PRO14040403