Internal Brace ACL Repair is Associated with High Failure Rate in the First Two Years Post-Surgery

OBJECTIVES: To compare graft/internal brace survival, self-reported functional outcomes, and joint laxity in adolescents who underwent quadriceps tendon patellar autograft (QPA) reconstruction versus ACL repair with internal brace ligament augmentation. METHODS: We identified all adolescent and pediatric subjects who underwent primary ACL reconstruction or repair with internal brace augmentation between January 2013 and January 2016. Only subjects with a minimum of 6 months of follow-up were included. Graft failure, range of motion (ROM), complications, and demographic information including age and gender was collected. Failure was defined as the need for revision surgery or MRI-confirmed graft/internal brace failure. Subjects were prospectively contacted by telephone and were invited to either schedule a follow-up appointment or to complete research questionnaires over the phone. Objective joint laxity measures, KT1000, were obtained from a subset of subjects (N=25 QPA and N=6 repair group) that completed the research visit. Wilcoxon rank sum tests were used to compare IKDC and joint laxity measure. Multi-variable Cox proportional hazards regression analyses were used to compare failure-free survival in the two groups during the first 24 months post-surgery. RESULTS: The final cohort included 132 patients in the QPA group (52% female) and 19 patients in the repair group (53% female). The repair group tended to be younger (mean: 14.1 yrs, ±2.9 vs 15.5 yrs, ±1.8). Median duration of follow-up was 2.1 years [range: 0.5-4 years] in the repair group compared to 1.2 years [range: 0.5-4 years] in the QPA group. Within the first 24 months post-surgery, the cumulative incidence of failure was 3.8% (5/132) in the QPA group compared to 52.6% (10/19) in the repair group. After adjusting for age, the hazard of failure in the repair group was 22.1 [95% CI: 6.7 to 73.2, p <0.0001] times the hazard of failure in the QPA group. KT-1000 side-to-side joint laxity measures in the repair group [Median: 2.5 mm, range: -1 mm to 7 mm] were significantly [p=0.0212] higher than the joint laxity measures in the QPA group [Median: 1.0 mm, range: -1 mm to 4 mm]. There was no difference [p= 0.3826] in IKDC scores in the repair group [N=53, median: 97, range: 58-100] compared to the QPA group [N=10, median: 94, range: 32-100]. CONCLUSION: Failure rate and joint laxity measures were significantly increased in the internal brace repair group relative to the QPA group. Failure-free survival in the repair group was less than 50% at two years.The high failure rate in the repair group should be considered when selecting the appropriate intervention for the pediatric adolescent athlete with an ACL injury.