Arthrofibrosis After Pediatric ACL Reconstruction: Associated Factors and Role of Graft Type, a Retrospective Study

BACKGROUND: Arthrofibrosis is a challenging complication that can occur after anterior cruciate ligament reconstruction (ACLR), restricting range of motion and impairing function. Risk factors have been identified for arthrofibrosis in adults, but data in pediatric patients are limited, particularly regarding the role of graft type. In this study, we compared clinical, surgical, and postoperative variables between pediatric patients who underwent ACLR with hamstring tendon (HT) autograft or quadriceps tendon (QT) autograft and assessed associations between arthrofibrosis development and postoperative clinical outcomes. METHODS: We retrospectively compared data from 154 pediatric patients (mean±SD age 15.1±1.8 years; 46% female) who underwent primary ACLR using HT (n=84) or QT (n=70) autografts from June 2015 to June 2024. We excluded patients with concomitant ligament injuries, prior ACLR, lateral extraarticular tenodesis, chondral procedures, or <5-month follow-up. Arthrofibrosis was defined as loss of ≥10 degrees of knee extension, loss of ≥20 degrees of knee flexion, or mechanical symptoms. Statistical analyses comprised Fisher exact tests, t tests, and Wilcoxon rank-sum tests. α=0.05. RESULTS: Compared with the HT group, the QT group had higher incidence of chondral injury (39% vs. 20%, P=0.020), higher incidence of positive Lachman test (100% vs. 85%, P=0.004), higher incidence of arthrofibrosis (7% vs. 0%, P=0.018), and a larger mean graft diameter (8.8±0.8 vs. 8.1±0.8 mm, P<0.001). The HT group had longer mean operative time (161±33 min) than the QT group did (142±35 min) (P<0.001). Patients who developed arthrofibrosis had less knee extension at 5 months postoperatively (9±0.6 degrees vs. -0.4±2 degrees, P=0.018) and greater incidence of additional surgery (100% vs. 14%, P<0.001) compared with those who did not develop arthrofibrosis. CONCLUSIONS: In pediatric patients who underwent ACLR, QT autografts were associated with higher incidence of arthrofibrosis and postoperative stiffness compared with HT autografts. These results suggest that graft selection may influence postoperative motion and should be tailored to individual patient factors, including concomitant chondral injury and baseline ligamentous laxity. LEVEL OF EVIDENCE: Level III.