Joint power distribution does not change within the contralateral limb one year after unilateral limb loss

Background: To assist with forward progression during gait, persons with unilateral lower-limb amputation typically perform more work within the unaffected versus affected limb. However, prior cross-sectional (>2years post-amputation) studies cannot necessarily elucidate the origin or evolution of these compensatory mechanics. Research question: Do lower limb joint kinetics change during the initial stages of independent ambulation among persons with lower-limb amputation? Methods: Nine males with unilateral lower-limb amputation (6 transtibial; 3 transfemoral) completed instrumented gait analyses (speed = 1.2 m/s) at 2 and 12-months post-independent ambulation. Within the unaffected limb, sagittal and frontal plane total positive and negative work, peak power, average positive power, and percent contribution of each joint were compared between time points using paired t-tests. Results: No differences existed between time points in total positive or negative work, at any joint (p > 0.038) in either plane. Similarly, there were no differences in percent contribution by each joint to total average power by sagittal (p > 0.15) or frontal (p > 0.32) planes. Significance: Persons with unilateral lower-limb amputation do not alter power distribution among joints within the unaffected limb during initial independent ambulation. However, compared to previous cross-sectional reports, smaller peak powers in the unaffected hip and knee here suggest mechanical work increases with time since amputation. Future research should longitudinally monitor segment mechanics to determine when deleterious strategies develop, as these have implications for joint degeneration and pain.