The thermogram of this patient’s knees demonstrate an obvious hyperthermic (hot) left knee. The patient had sustained an injury to the knee while skiing. She had been treated for a sprain with some relief, but the pain had not resolved long after the injury. The patient had just received an orthopedic follow-up exam with no change in her diagnosis. Since the thermogram showed a significant amount of residual inflammation, the patient was sent for an MRI. The MRI showed that the patient had a complete rupture of the anterior cruciate ligament.