Allograft Use Results in Higher Re-revision Rate for Revision Anterior Cruciate Ligament Reconstruction

BACKGROUND: The literature on revision anterior cruciate ligament (ACL) reconstruction (ACLR) outcomes is generally sparse, but previous studies have demonstrated that autograft use results in improved sports function and patient-reported outcome measures compared with allograft. However, knowledge is still lacking regarding the impact of graft type on rates of re-revision. PURPOSE: To investigate the clinical outcomes and failure rates of revision ACLRs performed with either allograft or autograft. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A search of the Danish Knee Ligament Reconstruction Registry identified 1619 revision ACLRs: 1315 were autograft procedures and 221 were allograft procedures (type of graft was not identified for 83 procedures). Clinical outcomes after 1 year were reported via the Knee injury and Osteoarthritis Outcome Score (KOOS), the Tegner activity score, and an objective knee stability measurement that determined side-to-side differences in instrumented sagittal knee laxity. Failure was determined as re-revision. Outcomes for revision were provided for the full life of the registry, up to 10 years. RESULTS: The re-revision rate was significantly higher for allograft compared with autograft (12.7% vs 5.4%; P < .001), leading to a hazard ratio for re-revision of 2.2 (95% CI, 1.4-3.4) for allografts compared with autografts when corrected for age. At 1-year follow-up, objective knee stability was significantly different (2.1 ± 2.1 mm for allograft vs 1.7 ± 1.8 mm for autograft; P = .01), and the KOOS subscale scores for symptoms, pain, activities of daily living, sports, and quality of life were 67, 76, 84, 49, and 46 for allograft and 67, 78, 84, 51, and 48 for autograft, respectively, with no difference between groups. CONCLUSION: In this observational population-based study, the ALCR re-revision rate was 2.2 times greater for allograft compared with autograft procedures. Allograft was associated with greater knee laxity at 1-year follow-up. However, subjective clinical outcomes and knee function were not inferior for allograft patients. These results indicate that autograft is a better graft choice for revision ALCR.