2015 ISAKOS Biennial Congress ePoster #1929

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

Jonathan Haskel, BS, Piscataway, NJ UNITED STATES
Tyler Uppstrom, BA, New York, NY UNITED STATES
Elizabeth B. Gausden, MD, New York, NY UNITED STATES
Daniel W. Green, MD, MS, FACS, New York, NY UNITED STATES

Hospital for Special Surgery, New York, NY, USA

FDA Status Cleared

Summary: This retrospective review of pediatric patients who underwent medial patellofemoral ligament (MPFL) reconstruction with hamstring autograft via a technique that uses an epiphyseal socket demonstrates safety to the adjacent physis while ensuring restoration of patellar stability.

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Abstract:

Background

Medial patellofemoral ligament (MPFL) reconstruction has become the preferred surgical treatment option for recurrent patellar instability in children and adolescents. Numerous surgical options for MPFL reconstruction have been described. Many of the approaches cite the risk of growth plate injury as a reason to avoid drilling sockets in skeletally immature patients. However, the incidence of growth plate injury secondary to MPFL reconstruction using femoral sockets has not been reported. The purpose of this study was to assess the short-term growth plate safety associated with femoral sockets for hamstring autograft fixation in pediatric MPFL reconstruction.

Methods

We retrospectively collected data on a consecutive series of patients that underwent MPFL reconstruction for recurrent patellofemoral instability by one surgeon at a tertiary care academic medical center between 2008 and 2014. Pre- and post-operative knee radiographs were collected for 113 patients (35 male, 78 female). Of these, we identified 51 patients with open growth plates at the time of surgery. Patients were excluded if a socket in the femur was not used (0 patients), or if the patient’s most recent radiographic follow-up occurred less than 1 year since the date of MPFL surgery (20 patients). Thirty-one patients (9 male, 22 female) met these criteria. For skeletally immature patients, a femoral socket was introduced within the epiphysis, just distal to the femoral physis. Femoral socket location was verified by intraoperative fluoroscopy. Of the 31 patients, all received a post-operative x-ray at a mean follow-up of 1.5 years, all received a clinical follow-up at a mean of 1.78 years, and 12 received a postoperative MRI on their operated knee. For patients that obtained an MRI, growth plate safety was assessed by observing the location of the femoral socket relative to the physis to rule out growth plate injury. Development of a lower limb angular deformity or limb length discrepancy was evaluated by examining post-operative standing hip-to-ankle anteroposterior radiographs, patient records, and clinical assessments.

Results

Thirty-one patients with an average age at surgery of 13 years were included in the analysis. Ninety percent of the patients (28/31) reported no subsequent patellar dislocations in the treated knee at most recent clinical follow-up. None of the patients developed an angular deformity or limb length discrepancy at clinical follow-up. Of the 12 patients that obtained a postoperative MRI, all 12 showed femoral sockets positioned distal to the physis without growth plate violation.

Conclusions

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 that undergo medial patellofemoral ligament (MPFL) reconstruction. We have demonstrated that using fluoroscopic assistance to place the femoral socket distal to the distal femoral physis in MPFL reconstruction is a reliable and safe method for avoiding physeal injury in children with patellar instability.