Lateral Patellar Dislocations: A Comparative MRI Study of Quantitative and Morphological Risk Factors of Patellofemoral Regions in St. Luke’s Medical Center, Global City Setting

Acute patellar dislocations are common injuries in children, accounting for approximately 9–16% of acute knee trauma in young athletes with hemarthrosis. Incidence rates in the American setting published in the American Journal of Sports Medicine for ages 10–17 were found to be about 29 per 100,000 persons per year, while the adult population average for this type of injury ranged between 5.8 and 7.0 per 100,000 persons per year. The highest rates of patellar dislocation were found in the youngest age groups, while the rates declined with increasing ages. Recognition of patellar dislocation is important, as it can lead to recurrent patellar instability, chronic anterior knee pain and prolonged limitation of function.

MR imaging is increasingly being applied to the evaluation of pediatric knee injuries, as it provides accurate and timely assessment of bone, cartilage, ligaments, menisci, and adjacent soft tissues. Qualitatively, several morphologic features can be assessed, such as bone signals, cartilage and osteochondral injuries, as well as tendinous and ligamentous defects. Quantitatively, six measurable values can be obtained, namely the lateral trochlear inclination, trochlear facet asymmetry, trochlear depth, tibial tuberosity-trochlear groove distance, sulcus angle, and patellar height ratio.

This is a cross sectional retrospective study. Prospective subjects include pediatric and adult patients diagnosed with lateral patellar dislocation based on MR imaging at St. Luke’s Medical Center in Global City. The data for review was from January 2010 to May 2016.

This study may serve as a guidefor orthopedic surgeons, both quantitatively and qualitatively, in the decision-making and improvement of patient outcomes in prevention and management of lateral patellar dislocation.