Pediatric Acute Lateral Patellar Dislocation: MRI Assessment of Medial Patellofemoral Ligament Injury Patterns and Associated Knee Pathologies

Background: We aimed to evaluate the relationship between the medial patellofemoral ligament (MPFL) injury pattern and accompanying anatomical factors, articular cartilage lesions, and knee soft tissue injuries in acute lateral patellar dislocation (ALPD). Methods: Knee MRIs of 102 children with ALPD were evaluated retrospectively. The location and severity of MPFL injury, associated anatomical variations, cartilage lesions, and injuries to the knee ligaments and menisci were assessed. Results: Partial MPFL tears were observed in 53 patients, while complete MPFL tears were observed in 49 patients. The injury site was at the patella insertion in 77 patients (77.5%). Trochlear dysplasia and patella alta were present in 86.3% of the patients. Wiberg type B and C patellae were observed in 50 patients each. Patellar cartilage lesions were seen in 45 patients (44.1%) and were more common in complete MPFL tears (p < 0.001). Patellar cartilage lesions were more prevalent in the patellar insertion (PAT) subgroup (p = 0.005). Medial collateral ligament (MCL) injury was observed in 55 patients and was more prominent in complete MPFL tears (p = 0.002). Lateral collateral ligament (LCL) injury was observed in 28 patients (27.5%) and was more common in the PAT subgroup (p = 0.002). Muscle injury was observed in 12 patients (11.8%). Conclusion: In children with ALPD, MPFL injury is more commonly partial and occurs at the patellar insertion site. Cartilage lesions are more frequently observed in cases of complete MPFL tears. MRI is a valuable tool in determining the location and severity of MPFL injury and in evaluating associated cartilage and ligament pathologies.