Article

After unilateral total knee arthroplasty (TKA), rehabilitation specialists often
constrain knee angles or foot positions during sit-to-stand, to encourage
increased weight bearing through the operated limb. Biomechanical studies often
constrain limb position during sit-to-stand in an effort to reduce variability.
Differences between self-selecting or constraining position are unknown in
persons after TKA. Twenty-six subjects with unilateral TKA participated in motion
analysis. Subjects performed the sit-to-stand using a self-selected position
(ssSTS); next, trials were collected in a constrained condition (ccSTS), where
both knees were positioned with the tibia vertical, perpendicular to the floor.
Repeated measures ANOVA (limb x condition) assessed differences between limbs and
between conditions. Subjects used greater hip flexion bilaterally during ccSTS
(91 degrees) compared to ssSTS (87 degrees; p=0.001) and knee flexion on the
non-operated limb was greater during ssSTS (84 degrees) compared to ccSTS (82
degrees; p=0.018). The ccSTS resulted in larger extensor moments on the
non-operated limb at the hip (ssSTS -0.473, ccSTS -0.521; p=0.021) and knee
(ssSTS -0.431, ccSTS -0.457; p=0.001) compared to the operated limb. The ccSTS
exacerbated the asymmetries at the hip and knee compared to ssSTS, and did not
improve use of the operated limb. Reliance on the non-operated limb may put them
at risk for progression of osteoarthritis in other joints of the lower
extremities.

Langue : ANGLAIS