Anterior knee pain and patellar instability: Diagnosis and treatment

Patellofemoral (PF) pain syndrome is not a diagnosis but a description of the complaints of the patient. One must try to identify a specific cause for the patient's knee pain since not all anterior knee pain will be treated in the same way. PF pain can occur without a history of blunt trauma or patellar instability, and can be present without objective anatomical malalignment. The pain frequently presents when sitting with flexed knees for a prolonged period or when climbing/descending stairs. The source of this pain is speculative. The pain can mechanically be induced by increased intraosseus pressure, by irritation of peripheral nerve ends, and/or by chemical production of different cytokines. Due to the loss of tissue homeostasis or altering the envelope of tissue acceptance, pain can occur (1). Currently some objective tests exist that support these theories as a potential source of pain.