Relationship between knee muscle activation and morphological changes in the infrapatellar fat pad in patients with...

The infrapatellar fat pad (IFP) plays a role in the mechano-pathology of patients with knee osteoarthritis (OA), and its morphological changes during walking may serve as an indicator for detecting the condition. However, the effects of knee muscle activation on IFP morphology during walking in patients with knee OA remain unclear. This study investigated the relationship between muscle activation and morphological changes in the IFP during walking in patients with knee OA. Twenty-two patients with knee OA were enrolled in this cross-sectional study. IFP thickness and kinematic and kinetic data were measured during walking using ultrasound imaging and a three-dimensional motion analysis system. The activities of the quadriceps and hamstring muscles were recorded simultaneously, and muscle co-contraction indices were calculated. No correlation was found between quadriceps activation and IFP parameters. By contrast, a significant negative correlation was observed between morphological changes in the IFP and lateral muscle co-contraction during the stance phase. These results suggest that co-contraction of knee muscles involves poor IFP dynamics during walking, potentially playing a role in the development of mechano-pathological changes in patients with knee OA.