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

The goal of this observational study is to learn about the outcomes of medial patellofemoral ligament (MPFL) reconstruction for the treatment of recurrent patellar instability. The main questions it aims to answer are: - What are the risk factors for recurrent patellar instability after MPFL reconstruction? - What functional outcomes do patients report after MPFL reconstruction? Participants undergoing MPFL reconstruction will answer survey questions about their knee and activity level 1 year and 2 years after surgery.

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

Conditions:
• Patellar Dislocation
• Recurrence
• Patella Fracture