Management of the First Patellar Dislocation

Abstract

First patellar dislocation is defined as a clinical entity that usually causes a traumatic disruption of the previously uninjured medial restraints of the patella with consequent hemarthrosis of the knee. Traumatic primary patellar dislocation is almost always associated with hemarthrosis, MPFL injury, and medial retinacular disruption. Clinically, 94–100 % of patients suffer from MPFL rupture after acute patellar dislocation. The initial evaluation of a first-time patellar dislocation should include an appropriate patient history, family history of patellar dislocation or hyperlaxity, and physical examination. MRI is recommended to be performed quite soon after the injury to verify the diagnosis, evaluate additional injuries, asses the cartilage more precisely, classify the MPFL injury, and describe the anatomic factors of the patellofemoral joint. The initial management of a first-time traumatic patellar dislocation is controversial with no evidence-based consensus to guide decision-making. Conservative treatment has been historically suggested for patients with primary patellar dislocation. A short immobilization period is used for patient comfort and is followed by formal physiotherapy. Therefore, the optimal conservative management has yet to be established. The surgical treatment should be considered in specific conditions. These include the finding of an osteochondral fracture, a substantial disruption of the MPFL, and a laterally subluxated patella with normal alignment of the contralateral knee.