Knee loading patterns of the non-paretic and paretic legs during post-stroke gait.

BACKGROUND: Post-stoke gait disorders could cause secondary musculoskeletal complications associated with excessive repetitive loading. The study objectives were to 1) determine the feasibility of measuring common proxies for dynamic medial knee joint loading during gait post-stroke with external knee adduction (KAM) and flexion moments (KFM) and 2) characterize knee loading and typical load-reducing compensations post-stroke.

METHODS: Participants with stroke (n=9) and healthy individuals (n=17) underwent 3D gait analysis. The stroke and healthy groups were compared with unpaired t-tests on peak KAM and peak KFM and on typical medial knee joint load-reducing compensations; toe out and trunk lean. The relationship between KAM and load-reducing compensations in the stroke group were investigated with Spearman correlations.

RESULTS: Mean (SD) values for KAM and KFM in the healthy group[KAM=2.20 (0.88)%BW*ht; KFM=0.64 (0.60)%BW*ht] were not significantly different from the values for the paretic [KAM=2.64 (0.98)%BW*ht; KFM=1.26 (1.13)%BW*ht] or non-paretic leg of the stroke group[KAM=2.23(0.62)%BW*ht; KFM=1.10 (1.20)%BW*ht]. Post hoc one sample t-tests revealed greater loading in stroke participants on the paretic (n=3), non-paretic (n=1) and both legs (n=2) compared to the healthy group. The angle of trunk lean and the angle of toe out were not related to KAM in the stroke group.

DISCUSSION: Measurement of limb loading during a gait post-stroke is feasible and revealed excessive loading in individuals with mild to moderate stroke compared to healthy adults. Further investigation of potential joint degeneration and pain due to repetitive excessive loading associated with post-stroke gait is warranted.