Idiopathic Medial Patellar Instability Treated with Lateral Patellofemoral Ligament Reconstruction Using Semitendinosus Allograft

Medial patellar instability is a potentially severe ligamentous condition that significantly impairs normal knee function, with most cases due to iatrogenic injury to the lateral soft tissue restraints. Idiopathic causes are exceedingly rare. We present a unique case of a 32-year-old woman with chronic idiopathic medial patellar instability managed with LPFL reconstruction using a semitendinosus allograft. This report contributes to the limited literature on non-iatrogenic medial patellar instability and supports LPFL reconstruction as a viable treatment option.