Medial Patellofemoral Ligament Reconstruction

In the general population, the overall incidence of acute patellar dislocation is 5.8 per 100,000 people in the United States1. The rate of patellar dislocation is estimated to be highest in the age group of ten to seventeen years, with reported rates of 29% to 43%1-3. Women have a 33% increased prevalence of acute patellar dislocation compared with men1. Patellar instability typically occurs in patients with several anatomic risk factors, including both soft-tissue and osseous abnormalities. Conlan et al. studied twenty-five cadaveric specimens to analyze soft-tissue restraints associated with patellar instability and found the medial patellofemoral ligament to be a critical medial soft-tissue restraint in preventing lateral instability4. Furthermore, biomechanical and radiographic findings have led many surgeons to state that disruption of the medial patellofemoral ligament is the “essential lesion” required for patellar dislocation1,4-7. Disruption of the medial patellofemoral ligament was diagnosed on magnetic resonance imaging (MRI) in twenty-six (96%) of twenty-seven patients8; the lesion most commonly occurs at the femoral attachment site9,10 (Fig. 1). In addition, the deep capsular layer, the medial patellomeniscal ligament, and the medial patellotibial ligament all have been found to contribute to the soft-tissue stabilization of the patella against lateral …