A patient experiencing knee pain localized to the lateral femoral condyle during running most likely has which condition?

The most likely condition for a patient experiencing knee pain localized to the lateral femoral condyle during running is iliotibial band friction syndrome. This condition is characterized by irritation and inflammation of the iliotibial band, which runs along the outside of the thigh and can cause pain at the lateral aspect of the knee, particularly over the lateral femoral condyle. Pain is typically exacerbated by repetitive knee flexion and extension, common in activities like running.

Understanding the biomechanics involved with this syndrome helps clarify the source of pain. As the knee flexes and extends during running, the iliotibial band can repeatedly slide over the lateral femoral condyle, leading to friction and subsequent inflammation and pain.

In contrast, other listed conditions relate to different anatomical locations or mechanisms. Osgood-Schlatter disease typically presents as pain and swelling below the knee at the tibial tuberosity due to stress on the growth plate. Pes anserine bursitis involves pain on the medial side of the knee, associated with irritation of the bursa positioned between the medial collateral ligament and the tendons of the sartorius, gracilis, and semitendinosus muscles. Lastly, patellar tendinitis (jumper’s knee)