No difference in revision risk between autologous hamstring graft less than 8mm versus hybrid graft 8mm or larger in anterior cruciate ligament reconstruction.

Abstract

Hamstring autograft (HA) is commonly used for primary anterior cruciate ligament reconstruction (ACLR). However, if the harvested HA is inadequate in diameter, it is often augmented with an allograft tendon, forming a hybrid graft (HY). This study sought to evaluate aseptic revision risk following HA versus HY ACLR. A retrospective cohort study was performed using data obtained from our healthcare system's ACLR registry. Patients ≤ 25years of age who underwent primary isolated ACLR were identified (2005-2020). Graft type and diameter size was the primary exposure of interest: < 8mm HA and ≥ 8mm HY. A secondary analysis was performed to examine 7mm HA and 7.5mm HA vs ≥ 8mm HY. Propensity score-weighted Cox proportional hazard regression was used to evaluate the risk of aseptic revision. The study sample included 1,945 ACLR: 548 ≥ 8mm HY, 651 7mm HA, and 672 7.5mm HA. The crude cumulative aseptic revision probability at 8-years for ≥ 8mm HY was 9.1%, 11.1% for 7mm HA, and 11.2% for 7.5mm HA. In adjusted analysis, no difference in revision risk was observed for < 8mm HA (hazard ratio [HR] 1.15, 95% confidence interval [CI] 0.72-1.82), 7mm HA (HR 1.23, 95% CI 0.71-2.11), or 7.5mm HA (HR 1.16, 95% CI 0.74-1.82) compared to ≥ 8mm HY. In a US-based cohort of ACLR patients aged ≤ 25years, we failed to observe any differences in aseptic revision risk for HA < 8mm compared to HY ≥ 8mm. Augmentation of a HA as small as 7mm is not necessary to prevent a revision surgery. Level III.