Rheumatology: 14. Diagnosis and management of anterior knee pain.

A 32-year-old male runner visits his family physician in late spring complaining of pain in his knees over the past month. The pain is mostly anterior but is not well localized. It is aggravated by running, especially on hills, but subsides after the patient stops running. The patient has kept fit during the winter by swimming and occasional cross-country skiing. He has no history of obvious trauma or a noticeable injury.