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

Abstract

PurposeHamstring 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. MethodsA retrospective cohort study was performed using data obtained from our healthcare system’s ACLR registry. Patients ≤ 25 years of age who underwent primary isolated ACLR were identified (2005–2020). Graft type and diameter size was the primary exposure of interest: < 8 mm HA and ≥ 8 mm HY. A secondary analysis was performed to examine 7 mm HA and 7.5 mm HA vs ≥ 8 mm HY. Propensity score‐weighted Cox proportional hazard regression was used to evaluate the risk of aseptic revision. ResultsThe study sample included 1,945 ACLR: 548 ≥ 8 mm HY, 651 7 mm HA, and 672 7.5 mm HA. The crude cumulative aseptic revision probability at 8‐years for ≥ 8 mm HY was 9.1%, 11.1% for 7 mm HA, and 11.2% for 7.5 mm HA. In adjusted analysis, no difference in revision risk was observed for < 8 mm HA (hazard ratio [HR] 1.15, 95% confidence interval [CI] 0.72–1.82), 7 mm HA (HR 1.23, 95% CI 0.71–2.11), or 7.5 mm HA (HR 1.16, 95% CI 0.74–1.82) compared to ≥ 8 mm HY. ConclusionIn a US‐based cohort of ACLR patients aged ≤ 25 years, we failed to observe any differences in aseptic revision risk for HA < 8 mm compared to HY ≥ 8 mm. Augmentation of a HA as small as 7 mm is not necessary to prevent a revision surgery. Level of evidenceLevel III.

A hamstring autograft diameter ≤ 8 mm is a safe option for smaller, lighter and female athletes who want to return to pivoting sports after ACL reconstruction

“…According to most of the large ACL registry‐based cohort studies, hamstring autograft diameter is associated with the risk of ACL graft failure [6, 8, 11–14, 17, 18, 20, 22, 23, 25, 26, 29]. A hamstring graft diameter equal to or smaller than 8 mm is believed to increase ACL graft failure rates compared to grafts larger than 8 mm [6, 8, 13, 14, 18, 26].…”