A 69-year-old man was referred to physical therapy by his primary care physician for an insidious onset of right medial knee pain that had been present for over 4 weeks. Due to the disproportionate response following initial management, he was referred to an orthopaedist for imaging. Magnetic resonance imaging revealed medial femoral condyle osteopenia, bone marrow edema, and subchondral bone collapse, and subsequently the patient was diagnosed with spontaneous osteonecrosis of the knee. J Orthop Sports Phys Ther 2018;48(10):824. doi:10.2519/jospt.2018.7923