Medial Patellofemoral Ligament Reconstruction in the Skeletally Immature Population using an Anatomic Physeal Sparring Technique (SS-23)

Abstract

The purpose of this study is to evaluate the success rate and clinical outcomes of a medial patellofemoral ligament (MPFL) reconstruction in a skeletally immature population using an anatomic physeal sparring technique. Between 2005 and 2011, forty-four skeletally immature consecutive knees with recurrent patellar instability (greater than 3 dislocations) underwent a primary MPFL reconstruction using either a gracilis or semitendinosus autograft. The surgical technique used in subjects with open physis requires the femoral origin of the MPFL reconstruction to be distal to the physis. This position was determined intraoperative by fluoroscopy. Presentation and radiographic data were retrospectively reviewed, while outcome measures, including the Kujala and Tegner activity scale, were prospectively collected. Thirty-five subjects with a minimum of one year were available for follow up. Between 2005 and 2011, the mean age of skeletally immature patient who underwent a MPFL reconstruction was 12.6 years (range: 7 - 15 years old). At a minimum of two years, the mean Kujala score was 93.2 and median Tegner scale of 6 in subjects who were not considered failures. Four subjects (11%) had recurrent patella dislocation or required revision stabilization procedures. No participants had evidence of physeal injury or arrest following the procedure. Between those who failed to those who did not fail, there was a trend for patellar alta (Insall-Salvati index 1.58 vs. 1.48) and trochlear dysplasia (lateral to medial facet ratio 2.34 vs. 2.2), in those who failed, however, these were not statistically significant differences (p value 0.29 and 0.30; respectively). A significantly higher tibial tubercle to trochlear groove distance was seen in subjects who failed their primary MPFL reconstruction (23.28 mm versus 16.65 mm; p value 0.02). An MFPL reconstruction in the skeletally immature patient with recurrent patellar instability is a safe procedure when using a femoral origin distal to the physis with good short-term success and a low failure rate.