Low Risk of Physeal Damage from a Medial Patellofemoral Ligament (MPFL) Reconstruction Technique that Uses an Epiphyseal Socket in Children

OBJECTIVES: The purpose of this study was to assess short-term distal femoral growth plate safety associated with femoral sockets for hamstring autograft fixation in pediatric MPFL reconstruction. METHODS: We retrospectively reviewed a consecutive series of 31 patients (22 females, 9 males) that underwent MPFL reconstruction by one surgeon at a tertiary care academic medical center between 2008 and 2014. Study inclusion criteria consisted of patients who were skeletally immature at the time of surgery, who had greater than 1 year radiographic follow-up and who had a femoral socket introduced during their procedure. Femoral socket location was verified by intraoperative fluoroscopy. All patients received a post-operative x-ray and a clinical follow-up. For the 12 patients that obtained post-operative MRI, growth plate safety was assessed by examining the location of the femoral socket relative to the physis to rule out growth plate injury (Figure 1). Development of lower limb angular deformities or limb length discrepancies was evaluated by examining post-operative standing hip-to-ankle anteroposterior radiographs, patient records, and clinical assessments. RESULTS: The average age at surgery of 13.0 years. The average length of radiographic follow-up was 1.5 years and the average length of clinical follow-up was 1.78 years. At most recent clinical follow-up, 90% (28/31) of patients reported no subsequent patellar dislocations in the treated knee. No patients showed evidence of an angular deformity or limb length discrepancy. Of the 12 patients with postoperative MRI, all showed femoral sockets positioned distal to the physis without growth plate disturbance. CONCLUSION: The use of an epiphyseal femoral socket for graft fixation presents minimal risk of physeal violation and ensures patellar stability in the majority of pediatric patients. We have demonstrated that using fluoroscopic assistance to place the femoral socket distal to the distal femoral physis is a reliable and safe method for avoiding physeal injury in children with patellar instability.