Medial meniscus extrusion during squatting is correlated with lower limb kinematics in patients with knee...

Increased medial meniscal extrusion (MME) under mechanical stress is a risk factor associated with progression of knee osteoarthritis (OA). Patients with knee OA often have unique features of abnormal kinematics during squatting, which might induce joint loading and increased MME; however, the detailed relationships involved remains unknown.

In this study, we investigated the effects of knee kinematics on increased MME during squatting in patients with knee OA.

Sixteen patients with symptomatic knee OA (mean age 56.31 ± 11.46 years) performed squatting in a laboratory setting. Three-dimensional motion analysis was collected focusing on tibial internal rotation, femoral posterior translation. MME dynamics were assessed using ultrasonography, and increases in MME on the waveform of the MME were calculated as the difference in MME between the two points of maximum and initial minimum flexion of the knee joint during squatting.

The waveform and peak of MME were in line with the tibial internal rotation. A significant positive correlation was found between the increase in MME and tibial internal rotation (r = 0.663, p = 0.007), but not the femoral posterior translation.

Greater tibial internal rotation was correlated with increased MME during squatting in patients with knee OA. These findings contribute to the understanding of the mechanical pathophysiology of knee OA.