A six camera motion analysis system with a force plate was used to investigate the differences between limbs in the heel strike transient vertical GRF and its relative timing, and hip, knee and ankle angles and moments at initial contact, as well as spatio-temporal parameters during the stance phase of walking in 19 subjects with unilateral knee replacement.
Paired t tests showed a significant difference in the contralateral limb relative to the operated limb in the heel strike transient magnitude (p = 0.03), hip moment (p = 0.01), knee moment (p = 0.02) and ankle moment (p = 0.03). No significant differences were found for the joint angles at heel contact or the spatio-temporal parameters (p > 0.05).
The heel strike transient magnitude was lower for the operated limb with no differences in the spatio-temporal parameters or the joint angles at initial contact between the limbs. Differences in the hip, knee and ankle moments were also found indicating an asymmetric loading of the impact force at initial contact on the lower extremity. The current findings may indicate an asymmetric loading on the knee joint and therefore may be clinically relevant in patients undergoing unilateral knee replacement.