Patellar Dislocation after Total Knee Arthroplasty for Neglected Chronic Post-traumatic Patellar Dislocation: A Case Report

Introduction Chronic post-traumatic dislocation of the patella is rare and results in persistent dislocation throughout the arc of motion of the knee. Whereas newborns with trochlear dysplasia may exhibit congenital patellar dislocation, typical delayed presentation in adults is often due to trauma and can progress to painful motion and secondary osteoarthritis. Although rare, recurrent dislocation is most commonly seen in females of late adolescence, is often familial, and approximately one-third are bilateral. Recurrent dislocation has been attributed to factors including inappropriate care following acute trauma, familial and/or anatomic predisposition, and ligamentous laxity. Miller et al. suggest that unilaterality, dislocation after adolescence, or adaptive changes could explain the delay in presentation and lack of significant functional changes. Treatment for chronic patellar dislocation focuses on restoration of native anatomic alignment and correction of any secondary destabilizing pathology, such as meniscal tears or loose bodies. Traditionally, treatment has included non-operative management with physical therapy, patellar realignment, or patellectomy. In the presence of osteoarthritis, a patellofemoral or total knee arthroplasty may be performed. We present a case of a patient with chronic post-traumatic patellar dislocation treated with total knee arthroplasty, who subsequently required a Corresponding author: Joshua C. Rozell, MD Department of Orthopaedic Surgery Penn Presbyterian Medical Center 1 Cupp Pavilion 39th and Market Streets Philadelphia, PA 19104, USA Phone: 215-662-3340 Fax: 215-349-5128 [email protected] Joshua C. Rozell, MD Pramod B. Voleti, MD Craig L. Israelite, MD