SEX, PATELLAR TENDON GRAFT, AND EARLY MOTION DEFICITS PREDICT ARTHROFIBROSIS AFTER PEDIATRIC ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

BACKGROUND: Arthrofibrosis remains a concerning early complication after anterior cruciate ligament reconstruction (ACLR) in children and adolescents. Previous studies suggest that those receiving patellar tendon (PT) autograft may be at higher risk than hamstrings tendon (HT), but there is little data regarding this complication in patients receiving quadriceps tendon (QT) autograft. PURPOSE: The purpose of this study is to identify risk factors for arthrofibrosis following pediatric ACLR with attention to graft type. METHODS: The medical records of patients that underwent primary ACLR at a single tertiary children’s hospital were reviewed for this retrospective cohort study. Those with multiligament reconstructions, lateral extra-articular tenodesis procedures, or a modified MacIntosh reconstruction were excluded. Arthrofibrosis was defined as a deficit of 10 degrees of extension and/or 20 degrees of flexion at 3 months after ACLR. Demographic data, intra-operative findings and techniques, and post-operative motion and complications were recorded. Univariate analysis was followed by purposeful entry logistic regression to control for confounding factors. RESULTS: A total of 378 patients were included in the analysis, of which there were 180 PT, 103 HT, and 95 QT grafts. The mean age was 15.9±1.7 years and 188 (49.7%) were female. In univariate analysis, the rate of arthrofibrosis was 1.9% for HT, 6.3% for QT, and 10.0% for PT (p=0.04). Females developed arthrofibrosis more frequently than males (10.6% vs. 3.2%, p=0.004). Additionally, those that ultimately experienced this complication had lower median flexion at 6 weeks after ACLR (88 vs. 110 degrees, p<0.001). After controlling for covariates in a multivariate model, PT graft raised the odds of arthrofibrosis 6.2 times compared to HT (95% CI 1.4-27.6, p=0.02), but there were no significant differences between QT and other graft types. Females were at 4.2 times higher odds than males (95% CI 1.6-10.8; p=0.003). Patients that were unable to attain 90 degrees of flexion 6 weeks after ACLR had 14.7 times higher odds of eventually developing arthrofibrosis (95% CI 5.4-39.8; p<0.001). Finally, those with an extension deficit of ≥5 degrees 6 weeks after ACLR had 4.7 times higher odds of experiencing this complication (95% CI 1.8-12.2, p=0.001). CONCLUSION: After adjusting for multiple covariates, PT autograft, female sex, and motion deficits at 6 weeks after ACLR (<90 degrees of flexion or extension deficit ≥5 degrees) were predictive of arthrofibrosis in children and adolescents. Quadriceps tendon autograft did not increase the risk of this complication.