Allograft use and fixed suspensory fixation increase revision risk in multiple revision anterior cruciate ligament reconstruction: A Swedish knee ligament registry study

PURPOSE: The purpose of this study was to assess the association between surgical-related variables, revision-free survival and knee injury and osteoarthritis outcome score (KOOS) following multiple revision anterior cruciate ligament reconstruction (mrACLR) using data from a national knee ligament registry. METHODS: A registry study was conducted using data from the Swedish knee ligament registry. All mrACLRs (n = 4012, two or more revisions) performed in patients over 18 years at the time of the index mrACLR surgery were considered for inclusion. The primary endpoint was time of graft failure (requiring subsequent revision). The secondary endpoints were patient-reported outcome failures at 1 and 2 years, defined as: (1) failure to achieve the patient acceptable symptom state (PASS) and independently (2) the minimal important change (MIC) on KOOS. Cox proportional hazards models and logistic regression analyses were used to determine the risk of treatment choices for graft failure with respect to the assessed variables. RESULTS: The final study cohort consisted of 918 patients who underwent mrACLR. The mean age was 26.4 ± 8.5 years, 52.5% were male, and bone-patellar tendon-bone autograft was the most commonly used graft type (61.0%). Allograft use was associated with a threefold increase in likelihood of undergoing re-revision compared to bone-patellar tendon-bone autograft (hazard ratio [HR] 3.06; 95% confidence interval [CI]: 1.24-7.60; p = 0.016). For femoral fixation, an adjustable suspensory device was associated with a lower likelihood of re-revision compared to fixed suspensory fixation (HR 0.30; 95% CI 0.10-0.92; p = 0.035). Femoral interference screw fixation was associated with nearly double the odds of failing to achieve the PASS on any one or more of the five KOOS subscales at 1-year follow-up (OR 1.94; 95% CI 1.20-3.13; p = 0.0069). Patients who underwent a concomitant cartilage procedure were more likely to achieve the MIC at 1-year (OR 0.42; 95% CI 0.22-0.80; p = 0.0084). CONCLUSION: Based on unadjusted registry analyses, allograft use was associated with an increased risk of re-revision compared to bone-patellar tendon-bone autograft, while adjustable suspensory femoral fixation was associated with a lower re-revision hazard than fixed suspensory fixation. These findings represent unadjusted associations and should be interpreted in the context of the study's observational design. LEVEL OF EVIDENCE: Level III, retrospective cohort study.