AOSSM/AANA Specialty Day 2020-Revision Risk of Soft-Tissue Allograft vs. Hybrid Graft Following Anterior Cruciate Ligament Reconstruction

Revision Risk of Soft-Tissue Allograft vs. Hybrid Graft Following Anterior Cruciate Ligament Reconstruction

Pdf Summary

This retrospective cohort study evaluated the revision risk after anterior cruciate ligament reconstruction (ACLR) using soft tissue allografts versus hybrid grafts (hamstring autograft augmented with soft tissue allograft) in patients aged 25 years or younger. Data from the Kaiser Permanente ACLR Registry from 2009 to 2016 included 2,080 primary isolated unilateral ACLRs, with 1,601 using soft tissue allograft and 479 using hybrid grafts. The median follow-up was 3.4 years.<br /><br />The study addressed a clinical dilemma: when hamstring (HS) autografts are deemed too small (<8 mm diameter), surgeons may opt for a small HS graft, harvest another autograft, augment the HS graft with allograft (hybrid graft), or use allograft alone. The relative revision risks of these options, particularly hybrid grafts versus allografts alone, remained unclear.<br /><br />Findings showed that the 2-year cumulative revision probability was higher for soft tissue allografts (5.4%) compared to hybrid grafts (3.8%). After adjustment for multiple covariates (age, BMI, sex, race/ethnicity, injury activity, allograft processing, fixation type, surgical technique, region, and surgeon), the hazard ratio for aseptic revision was two times higher for soft tissue allograft versus hybrid graft (HR = 2.0; 95% CI: 1.21–3.31; P = 0.007). <br /><br />Strengths included a large, racially and geographically diverse cohort, data from multiple surgeons and hospitals, and a dedicated registry with validated outcomes. Limitations involved the observational design limiting causal inference, possible unmeasured confounding variables, restriction to patients aged ≤25 years limiting generalizability, and lack of patient-reported outcomes.<br /><br />The study concludes that soft tissue allograft ACLR has a significantly higher revision risk compared to hybrid grafts in young patients. When faced with a small HS autograft, augmenting it with an allograft tendon (hybrid graft) may be preferable over abandoning it for soft tissue allograft alone. Further research is needed to evaluate indications and optimal hybrid graft diameters.

Keywords

anterior cruciate ligament reconstruction

ACL revision risk

soft tissue allograft

hybrid graft

hamstring autograft

young patients

cohort study

Kaiser Permanente ACLR Registry

graft augmentation

surgical outcomes