Integration into sport is an important milestone after anterior cruciate ligament reconstruction (ACLR); however, only 65% of individuals with ACLR will return to sport. After integrating into sport, the risk of a second ACL injury is 6 times greater in individuals with ACLR than in individuals without a history of ACL injury. Common obstacles to return to sport (RTS) and risks factors for second ACL injury like functional deficits, patient demographics, and psychological response to injury have been identified. Return to sport (RTS) criteria has been proposed to mitigate the risk of a second ACL injury, but has been criticized for insufficiently identifying individuals at heightened risk of ACL injury and for lack of relevance to sport related movement. More vigorous functional assessments are needed to identify individuals with ACLR at increased risk of a second ACL injury. Individuals with ACLR exhibit high-risk biomechanics during change of direction (COD) and it is commonly reported as a fear-evoking task in those with ACLR. Psychological response to injury after ACLR may negatively affect lower extremity biomechanics during COD and contribute to a second ACL injury due to increased muscle tension and decreased focus. However, limited research has been conducted in this area. Omission of COD assessment from RTS criteria is a major limitation in the current approach to identifying those prepared to integrate into sport after ACLR. Vigorous testing representative of sport demands in addition to nonmodifiable risk factors are needed to identify at risk individuals. The purpose of this study was to assess modifiable and nonmodifiable risk factors for second ACL injury and obstacles to RTS. Our central hypothesis is that demographic information, surgical characteristics, patient-reported outcome measures, and lower extremity biomechanics during fear-evoking tasks will identify individuals with ACLR at risk for a second injury. Ninety-one individuals with ACLR were assessed within 1-year of surgery on functional assessments, and patient-reported outcome measures. Follow-up interviews were collected 2-years after ACLR to collect return to sport status and second ACL injury status. Separate logistic regressions were used to assess the relationship between assessments collected 1-year after ACLR and return to sport status and incidence of second ACL injury. Older age, male sex, and meniscal procedure at the time of ACLR were predictive of return to sport status. Our models were unable to predict second ACL injury. Models for both outcomes were not enhanced with the addition of psychological outcome measures or functional data. Our results contribute to the growing concern that current RTS criteria does not adequately identify those at risk for a second ACL injury or those prepared to return to sport after ACLR. To identify unique demands during COD, 48 individuals with ACLR were assessed using a 3D motion capture system while performing a single leg drop vertical jump (SLV) currently used in RTS criteria and a single leg crossover hop (SLC), a COD task. Spearman’s Rho Correlation revealed moderate correlations between tasks during the amortization and acceleration phase. Deceleration and amortization time were longer during the COD task implying more time was needed to stabilize the knee and rotate the trunk toward the new trajectory, consistent with increased risk of ACL injury. COD did impose unique demands to suggest it should be assessed as part of RTS criteria. To assess the relationship between psychological response to injury and lower extremity biomechanics after ACLR, 46 individuals with ACLR were assessed on 3 psychological response to injury outcome measures and lower extremity biomechanics were assessed during a SLC using a 3D motion capture system. Spearman’s Rho Correlations showed positive psychological response to injury was associated with safer lower extremity biomechanics. Correlations in this study were weak and further investigation into the relationship between psychological response to injury and lower extremity biomechanics is warranted.
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