Article

Patients with total knee arthroplasty (TKA) frequently exhibit changes in gait
biomechanics post-surgery, including decreased ranges of joint motion and changes
in joint loading; however, the actions of the lower-limb muscles in generating
joint moments and accelerating the center of mass (COM) during walking are yet to
be described. The aim of the present study was to evaluate differences in
lower-limb joint kinematics, muscle-generated joint moments, and muscle
contributions to COM accelerations in TKA patients and healthy age-matched
controls when both groups walk at the same speed. Each TKA patient was fitted
with a posterior-stabilized total knee replacement and underwent patellar
resurfacing. Three-dimensional gait analysis and subject-specific musculoskeletal
modeling were used to determine lower-limb and trunk muscle forces and muscle
contributions to COM accelerations during the stance phase of gait. The TKA
patients exhibited a 'quadriceps avoidance' gait pattern, with the vasti
contributing significantly less to the extension moment developed about the knee
during early stance (p=0.036). There was a significant decrease in the
contribution of the vasti to the vertical acceleration (support) (p=0.022) and
forward deceleration of the COM (braking) (p=0.049) during early stance; however,
the TKA patients compensated for this deficiency by leaning their trunks forward.
This significantly increased the contribution of the contralateral back extensor
muscle (erector spinae) to support (p=0.030), and that of the contralateral back
rotators (internal and external obliques) to braking (p=0.004). These findings
provide insight into the biomechanical causes of post-operative gait adaptations
such as 'quadriceps avoidance' observed in TKA patients.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS