A 19-year-old softball player presents to clinic with complaints of bilateral knee pain which has been ongoing for approximately three months. She denies a history of trauma to either knee. The onset has been insidious and slowly increasing over time. She reports worsening of her pain when playing catcher and climbing stairs. She locates the pain over her anterior knees. X-rays are obtained that are normal. Which of the following is the most likely diagnosis?
Chondromalacia Patellae
(aka patellofemoral syndrome)