Motion analysis after total knee arthroplasty

The aim of this study is to evaluate the functional performance after total knee replacement (TKR). Two groups of patients, one with mobile (n = 9) and one with fixed bearing (n = 8) total knee prosthesis, were compared by means of motion analysis. A group of healthy subjects (n = 8), matched by age, were used as controls. Kinematics, kinetics and electromyography data were collected during physiological daily activities such as walking and squatting. During walking, both groups of patients showed a speed of progression, a maximum knee extension moment (stance phase) and a maximum knee flexion (swing phase) significantly lower than the control group. Moreover, during the swing phase a co-contraction of the antagonistic muscles of the inferior limb was present. During squatting, both groups of patients showed a peak of knee flexion significantly lower than the control group. Motion pattern after TKR is unphysiological but the abnormalities seem to be independent from the differences in the implant designs.