The purpose of this cross-sectional, observational study is to evaluate the relationship between quadriceps muscle quality-specifically muscle echogenicity and thickness change during isometric contraction-and clinical outcomes such as pain, physical function, quality of life, and Patient Global Assessment (PtGA) in female patients with knee osteoarthritis. Participants will undergo a non-invasive ultrasound evaluation of their thigh muscles and complete standard clinical questionnaires to help determine how muscle structural and functional properties impact the daily lives of patients with knee osteoarthritis.