Load carriage influences intact limb knee loading estimate associated with osteoarthritis in individuals with transtibial amputation.

Background: Load carriage can exacerbate the elevated intact limb knee loading in individuals with transtibial amputation, potentially contributing to osteoarthritis. Prosthetic foot mechanical properties like push-off power have the potential to reduce this elevated knee loading. This study investigated how load carriage position and prosthetic foot type affect intact limb knee loading measures for these individuals.

Methods: Twelve participants with unilateral transtibial amputation were recruited. Intact limb external knee adduction and flexion moments were analyzed, with prosthetic push-off power and work quantified for effects on first peak knee adduction moment. A linear mixed-effects regression evaluated the effects of load position and prosthetic foot on these metrics.

Results: Participants exhibited the smallest first peak knee adduction moment and impulse with the intact-side load condition, followed by the back load and front load conditions, with the prosthetic-side load condition having the highest magnitude (20-35 % increase). However, we found no significant differences in these metrics by prosthetic foot. Additionally, load position and prosthetic foot did not significantly affect peak knee flexion moment. Only a negative trend toward correlation (P = 0.089) was observed between first peak knee adduction moment and prosthetic push-off work in the back load condition.

Conclusions: Intact-side load carriage may be more clinically beneficial for mitigating the risk of increased intact limb knee loading. Further, load carriage strategy affects intact limb knee loading more than specific prosthetic foot type. These biomechanical findings can help guide rehabilitative load carriage strategies to minimize the elevated risk of knee osteoarthritis in individuals with transtibial amputation.