Investigation of the Effects of Prosthetic Knee Condition on Novice Transfemoral Amputee Runners
Date of Award
Master of Science (MS)
Some unilateral transfemoral amputees (TFAs) run in a prosthesis with an articulating prosthetic knee, others choose to run without a knee (prosthetic socket and foot are linked via a straight, non-articulating pylon) to increase stability. Research regarding unilateral TFA running with an unlocked versus locked prosthetic knee (approximately equivalent to the no-knee condition) with respect to energy cost and temporal metrics is limited; no studies have investigated the impact of knee condition on kinematic metrics. The purpose of this study was to investigate whether the prosthetic knee of a running-specific prosthesis (RSP) should be unlocked or locked for unilateral TFAs during recreational treadmill distance running. Five male TFA novice runners, aged 52-59 years, completed one training and one testing session running with the knee of a RSP in the unlocked and locked conditions. The testing session included two three-minute self-selected running speed (SSRS) trials (one trial for each knee condition) as well as six peak speed trials (three trials per knee condition). Temporal, kinematic, and oxygen consumption data were acquired during the SSRS trials. Paired t-tests and Wilcoxon signed-rank tests were conducted to identify significant differences between knee conditions. Statistically significant differences were observed between knee conditions for running economy (RE); mean RE was lower (suggesting greater efficiency) for the unlocked knee condition. Peak running speed did not differ significantly between knee conditions. Significant differences between knee conditions were also observed for peak hip flexion and abduction of the prosthetic limb during swing; maximum prosthetic limb hip flexion increased and prosthetic limb hip abduction was reduced for the unlocked knee condition. These differences contributed to reduced kinematic asymmetry at the hip for the unlocked knee condition; the unlocked knee condition also resulted in less asymmetry in hip range of motion. These differences in RE and hip kinematics between knee conditions may be attributed to circumduction of the prosthetic limb during swing to provide foot clearance with the locked knee condition. For novice recreational runners, the unlocked knee condition may be advantageous for TFAs during treadmill running, provided the individuals have sufficient endurance and cognitive focus to prevent knee buckling.