JUPITER 4.0 - Risk Factors for Failure of Isolated Medial Patellofemoral Ligament Reconstruction

Inclusion Criteria: * 10-35 years old * Recurrent patellar instability with at least one episode defined as either (1) a dislocated patella requiring reduction in the emergency department or (2) a convincing history for dislocation, associated with full giving way, and the following physical findings: (a) hemarthrosis or effusion, (b) tenderness along the medial retinaculum, and (c) apprehension when laterally directed force was applied to the patella or (3) MRI-documented dislocation with associated bone bruises Exclusion Criteria: * Previous ipsilateral knee surgery * Obligatory/fixed/habitual patella dislocation or subluxation * Unloadable inferior or lateral chondral damage on the patella that would require a tibial tubercle transfer for unloading purposes * Pathologic tibiofemoral instability