Gait biomechanical analysis of unaffected knee before and 6 months after total knee arthroplasty

Study aim: This study aimed to compare gait biomechanical data on the unaffected side before and six months after total knee arthroplasty (TKA) and determine the postoperative changes in medial knee loading on the unaffected side.

Material and methods: Three-dimensional gait analysis was performed on 19 female patients who had underwent TKA.

Gait parameters were extracted at each time point using the maximum value of the backward (braking phase) and forward components (propulsion phase) of the ground reaction force on the unaffected side, while the knee adduction moment impulse (KAM impulse) was used as an index of medial knee loading. The pre – and post-TKA values of these parameters were compared. The relationship between KAM impulse and gait biomechanical factors on the unaffected side was examined using partial correlation analysis with gait speed as a control factor.

Results: KAM impulse was not significantly different on the unaffected side compared to preoperatively. In the braking phase, there were significant differences in hip adduction moment (p = 0.033) and ankle dorsiflexion moment (p = 0.013), and hip flexion angle (p=0.011) in the propulsive phase. The relationship between KAM impulse and gait biomechanical factors on the unaffected side showed a positive correlation between KAM impulse and knee adduction angle (braking phase, propulsion phase; r = 0.671, 0.689) and KAM (braking phase, propulsion phase; r = 0.715, 0.745).

Conclusions: There was no significant difference in KAM impulse on the unaffected side before and after TKA, suggesting that TKA did not influence medial knee loading increase on the unaffected side even six months post-TKA.