A 30-year-old man comes to the office because of burning pain on the lateral side of his right knee. It began around the time he started training for a triathlon, but he does not remember any inciting incident. He also weight lifts and does yoga regularly. The pain occurs during his training sessions and now persists for some time afterwards. Physical examination shows focal tenderness with compression to the right lateral femoral epicondyle as the right knee is extended from 90° to 30°. Which of the following is the most likely diagnosis?

Iliotibial band syndrome (ITBS)

Lateral collateral ligament (LCL) injury

Patellofemoral pain syndrome (PFPS)

Iliotibial band syndrome

Summary of Iliotibial band syndrome

Iliotibial band syndrome is one of the leading causes of lateral knee pain in runners. The iliotibial band is a thick band of fascia on the lateral aspect of the knee. The band is crucial to stabilizing the knee during running, as it moves from behind the femur to the front of the femur during activity. The continual rubbing of the band over the lateral femoral epicondyle, combined with the repeated flexion and extension of the knee during running may cause the area to become inflamed.