Bilateral Anterior Knee Pain in a High School Cross-Country Runner: An Atypical Etiology.

Anterior knee pain is a common complaint found in distance runners, and can be the end result of a variety of benign processes. A 17-year-old female cross-country runner presented to a sports medicine clinic with insidious onset of bilateral patellofemoral pain (PFP). In the workup of the significant quadriceps weakness discovered on her initial examination, a principal contributing cause of her PFP, she was found to have a form of spinal muscular atrophy, an uncommon neurodegenerative disease that typically requires multidisciplinary medical care. Her case provides a good example for clinicians to consider, at times, an in-depth assessment of the root causes of benign conditions.