ACLR GRAFT STRAND NUMBER: LONG-TERM FOLLOW-UP ON 400 PATIENTS

BACKGROUND: Studies on pediatric anterior cruciate ligament reconstructions (ACLRs) often focus on graft choice, as rates of these injuries have risen in recent years. Large multicenter studies have found younger age and smaller graft size to be risk factors for graft failure and contralateral tears, but despite large sample sizes these studies have not looked specifically at graft strand number. Therefore the purpose of this study was to use a large sample size to ask whether ACLR graft strand number affects long-term outcomes. HYPOTHESIS/PURPOSE: Examine long-term effects of ACLR graft strand number using a large cohort. METHODS: This was a retrospective comparison study of all patients presenting between 1/1/2008 and 12/31/16 for a first-time ACLR at a single pediatric hospital. After querying medical records for all ACLRs using CPT codes, graft strand number, graft diameter, and other variables were abstracted. Long-term outcomes on graft rupture, contralateral ACL tear, and subsequent meniscus injury were collected via phone calls and REDCap emails. Patient groups were compared for differences in graft strand number and diameter using bivariate analyses, and differences in long-term outcomes were analyzed using multivariate regression. RESULTS: 436 patients met the inclusion criteria also completed the long-term follow-up on outcomes. Long-term follow-up ranged from 18 months post surgery to 10 years post surgery. Patients with larger graft diameter were significantly less likely to suffer a complication (graft rupture, contralateral ACL tear, or subsequent meniscus injury) in multivariate regression (p=0.03), while strand number, sex, weight, and age showed no significant difference. Transphyseal reconstructions had larger graft diameters (8.8mm) than partial hybrid (8.6mm) and all-epiphyseal reconstructions (8.3mm) (p<0.001), but had no differences in graft strand number. Males had larger graft diameters (8.9mm) than females (8.6mm) (p=0.03), but also had no differences in graft strand number. Obese patients had larger graft diameters (9.1mm) than overweight (8.9mm) and normal weight patients (8.6mm) (p=0.002). Obese patients also had more graft strands (6.9) than overweight (6.2) or normal weight patients (6.1), but this difference was not significant (p=0.051). CONCLUSION: This data supports the existing literature that pediatric ACLR patients with larger graft diameters are less likely to suffer long-term complications. Using both a large patient cohort and long-term follow-up, this data also showed that graft strand number was not significantly correlated with outcomes. This suggests that strand number is not important when constructing ACLR grafts, as long as sufficient graft diameter can be achieved.