Medial patellar instability: A little known cause of anterior knee pain

Abstract

Anterior knee pain (AKP) is one of the most common patient complaints heard by orthopedic surgeons. A wide variety of causes of AKP have been ascribed to it. Medial patellar instability (MPI) is an objective condition with its own personality provoking incapacitating AKP that should be included in the differential diagnosis of AKP patients, above all in disabling AKP patients after realignment surgery. However, this condition can be difficult to diagnose because it is not well described in the medical literature. Its clinical repercussion was identified at the end of the 1980s. We can now state that it is an objective cause of AKP and that it is more frequent than we had thought, although it might be underdiagnosed because it is still not a well-known entity. The first author has seen many patients with MPI who have seen more than three physicians without a true diagnosis of their condition.