Study Aim/Objectives:
To describe 2-year graft survival following paediatric ACLR and evaluate associations between patient/surgical factors and graft failure, with a focus on knee-joint morphology, including lateral femoral condyle index (LFCI), mechanical axis deviation (MAD), and posterior tibial slope.
Method:
Patients aged ≤16 years undergoing primary ACLR were included and prospectively followed. Morphological parameters were measured on pre-operative imaging using a blinded protocol. Follow-up was determined through registry capture, medical record review, imaging databases (including community MRI where available), and direct patient contact when required. The primary outcome was graft failure within 2 years, defined as MRI- or arthroscopically confirmed graft rupture, or clinical failure (symptomatic instability and/or objective laxity with GNRB side-to-side difference >5 mm). Kaplan–Meier methods estimated graft survival. Cox proportional hazards models assessed associations with time-to-failure, with censoring at last clinical follow-up.
Results:
Three hundred patients were included. Mean follow-up was 2.29 ± 1.13 years. Mean age was 14.5 ± 1.89, 47.5% were female and 30% were skeletally immature. There were 32 failures: 19 confirmed graft ruptures and 13 clinical failures. Estimated 2-year graft survival was ~90%. Univariate analysis found older age (HR 1.04 per year; 95% CI 1.02–1.06; p<0.001), lower LFCI (HR 0.94 per 0.01-unit increase; 95% CI 0.90–0.98; p=0.006), and intra-operative medial meniscus tear (HR 2.38; 95% CI 1.16–4.87; p=0.017) were associated with higher failure risk. In multivariate models, age remained associated with increased hazard (HR ~1.03–1.04; p≤0.005) and higher LFCI was protective (HR ~0.93–0.95 per 0.01; p=0.037). Medial meniscus pathology independently increased risk (HR 2.55; 95% CI 1.21–5.41; p=0.014). MAD, lateral meniscus condition, lateral tibial slope, and lateral extra-articular tenodesis (LET) were not significantly associated with failure. Dichotomised LFCI (<0.70 vs ≥0.70) showed worse survival in the low-LFCI group but did not reach significance (log-rank p=0.11).
Conclusions:
Two-year graft survival after paediatric ACLR in this cohort was ~90%. Increased age, decreased LFCI, and medial meniscus tears were the strongest predictors of graft failure, whereas coronal alignment and LET showed no clear independent association within 2 years. These factors may help identify patients at higher risk of failure for counselling and risk-stratified management.
