OVER-THE-TOP VERSUS ALL-EPIPHYSEAL TECHNIQUE FOR PHYSEAL SPARING ACL RECONSTRUCTION

Abstract

BACKGROUND A variety of techniques are utilized for physeal sparing ACL reconstruction, however, no clear consensus exists on the ideal surgical technique, the frequency of complications, and how to best avoid growth disturbance. The purpose of this systematic review is to compare outcomes and complications between over-the-top and all-epiphyseal ACL reconstruction techniques. METHODS The EMBASE and PubMed databases were queried for studies on ACL ruptures in the skeletally immature from 1985 to 2016. Full-text, English studies discussing operative intervention on skeletally immature patients with ACL tears were included (n = 160). Studies that reported re-rupture and/or complications after physeal sparing ACL reconstruction, specifically growth disturbance, were then included in a secondary analysis (n=10). Studies were separated into two groups: an all-epiphyseal group with femur and tibia fixation points within the epiphysis and a group that had over-the-top femur and tibia physeal-sparing reconstruction. Complications that were not specific to the pediatric population were excluded. Angular deformity greater than 3 degrees between the operative and non-operative extremities was used as the threshold. Patient demographics, evaluation of skeletal maturity and growth disturbance, graft type, surgical technique, follow up, growth disturbance, re-rupture, and patient reported outcome scores were collected. Data was analyzed in aggregate. RESULTS Ten studies were included with 280 knees in 279 patients. The average age was 11.8 years, 79% were male, and the mean post-operative follow up was 46.2 months. There were 178 patients who underwent all-epiphyseal reconstruction and 102 patients who underwent ACL reconstruction with the femoral graft placed in an over-the-top position. The overall re-rupture rate was 8.2% (23 of 280). There were 16 re-ruptures in the all-epiphyseal group (9%), and 7 re-ruptures in the over-the-top group (6.9%). Of those studies that specified treatment for re-rupture, 80% of patients required revision ACL reconstruction. Two studies did not conduct objective assessment of skeletal maturity. The majority of studies (50%) did not assess for baseline limb length inequality or angular deformity. 30% of studies performed routine hips-to-ankles bilateral lower extremity radiographs. 20% of studies assessed baseline LLD/angular deformity using clinical examination. Post-operatively, 50% of studies obtained routine hips-to-ankles lower extremity radiographs. 30% of studies obtained post-operative alignment imaging only if there was clinical suspicion of growth disturbance. There were ten total growth disturbances (3 required corrective surgery, or 30%). Seven knees developed limb overgrowth (six in the all-epiphyseal group (mean 1.8 cm) and one in the over-the-top group, 1.5 cm). Two of the patients with overgrowth from the all epiphyseal group required epiphysiodesis (28.6%). Five patients were observed. There were two angular deformities (one with 4 degrees of valgus, and another with 4 degrees varus), both in the over-the-top group which were treated with observation. There were no knees which developed angular deformity in the all epiphyseal group. One patient from the over-the-top group developed a multi-planar flexion-valgus deformity and required distal femoral osteotomy for correction. Five studies reported excellent Lysholm scores of 96.4. Six studies reported IKDC scores (range 88.5-100, 93% grade A or B). CONCLUSIONS / SIGNIFICANCE Growth disturbance after physeal sparing ACL reconstruction was overall uncommon and mild. The phenomenon of overgrowth was common likely due to younger patients receiving physeal sparing procedures. Overgrowth was more common in the all-epiphyseal group and angular deformity in the over-the-top group. Re-rupture rates were similar between the two groups. Evaluation of pre-operative skeletal maturity and comparison of baseline to post-operative growth disturbance was limited by lack of routine imaging assessment. We recommend routine PA hand radiographs, and pre- and post-operative hips-to-ankles alignment radiographs in all skeletally immature patients prior to undergoing ACL reconstruction. Further multi-center study with patient reported outcomes and long-term follow-up are necessary to determine the ideal reconstructive technique in the young, skeletally immature population.