Modification of Practice Patterns after Analysis of Risk Factors Improved ACLR Outcomes

OBJECTIVES: Retear of an ACL after an ACL reconstruction (ACLR) is devastating for all involved. Understanding risk factors and predictors of subsequent graft tear after an ACLR is vital for patient education of subsequent risk of injury and if modifiable risk factors are identified, adjustments can be made to minimize the risk of repeat ACL tear. The objective of this study was to compare retear risk between 2002-2003 and 2007-2008 MOON cohorts to determine if after an analysis of risk factors in the 2002-2003 cohort, a shift in clinical practice changed the risk profile of ACL graft tear in the 2007-2008 cohort. The 2002-2003 and 2007-2008 cohorts are subsets of a larger MOON cohort. METHODS: The prospectively collected data of the 2002-2003 and 2007-2008 primary ACLRs with >80% two year follow-up was analyzed. Graft type (autograft bone patellar bone (BTB), autograft hamstring, allograft), age, Marx score at time of index surgery, and sex were evaluated to determine their relative contributions to ipsilateral retear in the 2002-2003 cohort and 2007-2008 cohort separately. An ANOVA with post-hoc analysis was performed to detect significant differences in age and Marx score at time of index surgery by graft type between the 2002-2003 and 2007-2008 cohorts. RESULTS: A total of 1758 subjects met all inclusion/exclusion criteria. The mean age of subjects that received allograft rose by 8 years (p<0.01) from the 2002-2003 cohort to the 2007-2008 cohort, whereas the mean age of subjects that received BTB and hamstring remained constant over time [Fig 1]. The mean Marx score of subjects receiving allograft dropped by 2.7 points (p<0.01) from the 2002-2003 cohort to the 2007-2008, whereas the mean Marx score of cohort subjects that received BTB and hamstring remained constant over time [Fig 2]. Thus in 2002-2003, there were 38/815 (4.7%) retears compared to 34/943 (3.6%) in 2007-2008. The odds of retear for allograft subjects was 9.27 times higher compared to BTB autograft in the 2002-2003 cohort (p<0.01), which decreased to 5.63 times higher in the 2007-2008 cohort (p=0.01) [Table 1]. CONCLUSION: Age, activity, and graft type have been identified as predictors of increased risk of ipsilateral graft failure after ACLR. Allograft use in young active patients was shown to be a risk factor for graft tear in the 2002-2003 cohort. Subsequent to this determination, graft choice changed to use allografts in older and less active patients, which resulted in an associated decrease in graft tear risk in the 2007-2008 cohort. The risk of ACL graft retear was lower for all graft types in the 2007-2008 cohort compared to 2002-2003 cohort.