Date of Award

Fall 2005

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Biomedical Engineering

First Advisor

Silver-Thorn, Barbara

Second Advisor

Haris, Gerald F.

Third Advisor

Del Toro, David

Abstract

Prosthetic knee designs have become extremely sophisticated compared to early constant friction single axis mechanisms. Today, prosthetists and physicians have a wide variety of components to choose from for their transfemoral amputee patients. Unfortunately, there is little quantitative data comparing the performance of different types of prosthetic components, and prosthetic prescription is often based on empirical knowledge and experience, rather than objective comparisons of prosthetic designs. This study used gait analysis to objectively evaluate the stability characteristics of two types of prosthetic knee designs, the Total Knee 2000 and the 3R80. Five healthy, active transfemoral amputees participated in this study by completing two gait analysis sessions, one with the Total Knee 2000 and one with the 3R80. At the end of each session, subjects were asked to complete a questionnaire for use in comparing their subjective preferences with the objective biomechanical measures computed from the gait analysis data. Kinematic gait data were collected at 120 Hz using a video-based Vicon 524 Motion Analysis System (Vicon Motion Systems, Inc.; Lake Forest, CA) with 15 cameras. Kinetic gait data were collected at 1800 Hz by two AMTI ORS6-500 force plates (Advanced Mechanical Technology, Inc.; Watertown, MA). Gait data were processed through a Vicon Bodybuilder model, and the outputs from this initial stage were further processed with custom written MatLAB codes. Stride and temporal parameters (i.e. velocity, cadence, stride length, step length, stance and swing phase durations and single and double support durations), calculated hip moments, and required hip moments were computed from the Vicon data. A within subjects statistical analysis was then conducted, using a repeated measures ANOVA, to determine if there were significant differences in performance between the two knee designs. The stride and temporal parameters computed in this study indicated that the Total Knee 2000 demonstrated a higher degree of overall stability compared to the 3R80. The calculated hip moment values demonstrated that the different degrees of overall stability between the Total Knee 2000 and the 3R80 resulted in different hip moments. The required hip moment calculations indicated that the relative stability of the two knee designs changed throughout the gait cycle due to the polycentric nature of the Total Knee 2000. Specifically, the Total Knee 2000 was found to be less stable than the 3R80 in early stance and more stable than the 3R80 in mid- and late-stance. In addition to the biomechanical evidence of increased stability with the Total Knee 2000, the responses to the subjective questionnaires indicated that most subjects felt more stable and more confident bearing weight on the Total Knee 2000 than the 3R80.

Download

Share

COinS

Restricted Access Item

Having trouble?