Biomechanical assessment of Hoffa fat pad characteristics with ultrasound: a narrative review focusing on diagnostic imaging and image-guided interventions

The infrapatellar fat pad (IFP), a key intra-articular knee structure, plays a crucial role in biomechanical cushioning and metabolic regulation, with fibrosis and inflammation contributing to osteoarthritis-related pain and dysfunction. This review outlines the anatomy and clinical value of IFP ultrasonography in static and dynamic assessment, as well as guided interventions. Shear wave elastography (SWE), Doppler imaging, and dynamic ultrasound effectively quantify tissue stiffness, vascular signals, and flexion-extension morphology. Due to the limited penetration capability of ultrasound imaging, it is difficult to directly observe IPF through the patella. However, its real-time capability and sensitivity effectively complement the detailed anatomical information provided by MRI, making it an important supplementary method for MRI-based IPF detection. This integrated approach creates a robust diagnostic pathway, from initial assessment and precise treatment guidance to long-term monitoring. Advances in ultrasound-guided precision medicine, protocol standardization, and the integration of Artificial Intelligence (AI) with multimodal imaging hold significant promise for improving the management of IFP pathologies.