Seth L. Sherman, MD, and Daniel Curtis, MD

Medial patellofemoral ligament reconstruction is commonly performed in pediatric and adolescent patients with recurrent patellar instability. In general, results are excellent and complication rates are low.  However, the surgical procedure has some additional considerations when performed in skeletally immature patients. There are concerns about physeal risk with anatomic femoral graft placement and aberrant graft isometry with non-anatomic placement. Younger patient age and higher activity demand may also influence surgical results irrespective of the above graft-related factors.

Seth L. Sherman

Daniel Curtis

To help provide timely information, Quinlan and colleagues retrospectively examined a cohort of 120 pediatric (<18 years old) patients who underwent MPFL reconstruction for patellar instability with minimum 1-year follow-up. The results demonstrated no differences in IKDC, satisfaction, pain and sports participation between groups. Similarly, rates of recurrent patellar dislocation and revision instability surgery were similar between cohorts. However, there was a higher rate of subsequent knee injury (34% vs. 16%) in the skeletally immature group, as well as a lower percentage of patients who would elect to undergo the procedure again. Despite this, the results were encouraging in a challenging patient population, with an average IKDC of 79, a 9% rate of recurrent ipsilateral patellar dislocation and a 17% rate of revision instability surgery in the skeletally immature patients.

Strengths of this study include relatively large patient numbers in each cohort, consistent MPFL surgical technique and standardized rehabilitation protocol. Weaknesses include baseline sex difference between groups (ie, higher proportion of skeletally immature male patients), lack of information correlating exact location of graft placement or other anatomic risk factors (ie, lateralized force vector, patella alta, trochlear dysplasia) with outcome and lack of radiographic follow-up. Additionally, the authors report including Mersilene tape augmentation in the skeletally mature group at a significantly higher rate (68% vs. 13%). The indications for suture tape augmentation in MPFL reconstruction remain unclear and require continued scrutiny. Lastly, it is noted that the reported differences in subsequent knee injury risk may be inherent to the younger patient population with higher activity demand/risk profile without any clear association to specific graft-related factors.

Overall, the authors demonstrate that MPFL reconstruction can lead to excellent outcomes in skeletally immature patients which are similar to skeletally mature pediatric/adolescent patients. Further study, including large prospective studies, is required to answer many of the important residual questions.