Morphological changes of the infrapatellar fat pad during squat in patients with patellofemoral cartilage lesions.

BACKGROUND: Mechanical stress causes patellofemoral cartilage lesions. The role of the infrapatellar fat pad (IFP) is to adjust mechanical stress, and identifying changes to its morphology could enhance understanding of the features of a patellofemoral lesion. This study aimed to determine whether, during squatting, the dynamic IFP is a specific feature of patellofemoral cartilage lesions. METHODS: Twenty-four inpatients diagnosed with knee osteoarthritis were recruited. Dynamic IFP evaluation during squatting was performed using ultrasonography. This study used tracking software to determine the extent of flexion and extension during squatting, as observed on an ultrasound video. On magnetic resonance imaging, the Insall-Salvati ratio relating to the IFP area and patellofemoral alignment were obtained. Following arthroscopy evaluations, the patients were divided into healthy cartilage (n = 9) and abnormal cartilage (n = 15) groups. RESULTS: The IFP and Insall-Salvati ratios did not differ significantly between the groups. However, in the dynamic IFP evaluation, the extent of IFP extension movement was significantly lower in the abnormal cartilage group. CONCLUSIONS: Insufficient movement in terms of IFP dynamics during squatting is a feature of patients with patellofemoral cartilage lesions.