This prospective clinical study aims to establish normative values of knee ligament stiffness across different ethnic populations using shear wave elastography (SWE) and to investigate biomechanical alterations associated with knee osteoarthritis (OA). Healthy adults and patients with symptomatic knee OA will undergo standardized SWE examinations of the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL), together with clinical assessments. For patients who subsequently receive clinically indicated ultrasound-guided injection therapy, follow-up SWE and clinical evaluations will be performed to investigate changes in ligament stiffness after treatment.