Patellar dislocations

[Tracie Lynn]

Patellar dislocations are common and almost always lateral. Diagnosis is clinical; x-rays are taken to exclude fracture. Treatment is reduction and immobilization.

(See Overview of Dislocations.)

Patellar dislocation is distinct from knee dislocation, which is a much more serious injury.

Most patients are adolescent females and have an underlying chronic patellofemoral abnormality. Many dislocations spontaneously reduce before medical evaluation.

Usually, patellar dislocation occurs when people suddenly change direction or twist the knee or when force is applied to the knee (as may occur in soccer, gymnastics, or baseball when swinging a bat).

Associated injuries include

• Osteochondral fracture of the patella or lateral femoral condyle

Complications can include

• Osteoarthritis
• In patients with patellofemoral abnormalities, recurrent dislocation or subluxation