Acute and recurrent patellar instability in the young athlete.

Many reports of patellofemoral instability treatment suffer the same flaws of inappropriate patient selection, poor injury definition, insufficient activity assessment, and, especially in skeletally immature patients, limited followup found in other orthopedic literature. A significant number of dogmatic statements concerning risk factors and treatment interventions continue to be recycled through the literature without adequate clinical or laboratory substantiation, even in the face of contradictory data. Traditionally, patellar instability has been treated with variable periods of immobilization, sporadic rehabilitation, and an expected full return to sports activity. The reality is that many young athletes have long-term retropatella pain and sport-limiting extensor mechanism impairment following patellar dislocations. Most athletes benefit from an initial nonoperative program that is aggressive, multidimensional, and responsive to early treatment outcomes. Concurrent osteochondral injuries are common and a major contributor to adverse outcomes. Diagnostically, MRI is improving in its ability to detail osteochondral injury and it plays an important role in determining the location and extent of MPFL injury. The primary stabilizing role of the MPFL in the normal knee and its injury as an essential lesion of patella instability has been appreciated only recently. There is growing interest in exchanging the myriad of nonanatomic extensor mechanism reconstructions for more anatomic procedures based on restitution of the MPFL.