Correlation between rotational moments of the knee and other joints during gait, including the free moment of patients with a medial meniscus tear.

Purpose: Rotation of the knee puts stress on the medial meniscus and can be a factor in the progression of knee osteoarthritis. This study aimed to investigate the rotational moment (internal rotation and external rotation) of the knee during gait and relationship between the rotational moments of the knee and other joints, including the free moment during gait.

Methods: We included 18 patients with medial meniscus tears (MM group) and 10 asymptomatic participants in this study. We performed 3D gait analysis. The internal ankle, knee, and hip rotational moments as well as free moment were compared between the groups. Additionally, we investigated correlations between rotational moments of the knee and other joints during gait.

Results: The maximal knee external rotation moment in the MM group was smaller than that in the asymptomatic group ( p = 0.04, g = 0.76); however, there were no significant differences in the maximal internal rotation moment between the groups ( p = 0.97, g = 0.02). The internal rotation (external knee external rotation) moment positively correlated with the hip internal rotation moment ( p 〈 0.01, r = 0.69) in the MM group.

Conclusions: The internal rotation (passive knee external rotation moment) did not decrease sufficiently, and correlation was observed between moments of the knee and hip in the MM group, especially during the late stance phase of gait. Reducing these abnormal moments during gait through rehabilitation may be important in patients with medial meniscus tears to prevent rapid progression of knee osteoarthritis.