Chronic Flexion Patellar Dislocation with Femoral Patellofemoral Dysplasia and Anterior Bump: Treated by Distal Femoral Subtraction Osteotomy and Medial Patellofemoral Ligament Reconstruction - A Case Report.

Introduction: Chronic patellar dislocation during flexion is a rare condition associated with femoral dysplasia and dynamic patellar maltracking. The presence of an anterior femoral bump contributes to the mechanical conflict.

Case report: We report the case of a young adult with chronic patellar dislocation during knee flexion, associated with patellofemoral dysplasia, anterior bump, and lateral laxity.

Conclusion: Treatment consisted of a distal femoral anterior subtraction osteotomy combined with medial patellofemoral ligament reconstruction. Pre- and post-operative documentation as well as imaging demonstrate the correction of the instability.