Differential diagnosis in patients with disorders of the patellofemoral joint.

Anterior knee complaints are difficult diagnostic problems. It cannot be overstated that the most important information available is to be found in the patient's history. Onset, quality, and quantity of symptoms must be assessed. This information is then synthesized to determine the specific functional disabilities resulting from the patient's anterior knee disorder. Once a history is obtained, a consistent, methodical physical examination can be performed to narrow the differential diagnosis. Radiographic evaluation is used to further hone the differential or to confirm the most likely diagnosis. Ultimately, a specific working diagnosis is selected and treatment is tailored to changing the underlying structural or biomechanical abnormalities that led to the patient's complaints.