Comparison of Physical Impairment, Functional, and Psychosocial Measures Based on Fear of Reinjury/Lack of Confidence and Return-to-Sport Status After ACL Reconstruction

Background: Fear of reinjury and lack of confidence influence return-to-sport outcomes after anterior cruciate ligament (ACL) reconstruction. The physical, psychosocial, and functional recovery of patients reporting fear of reinjury or lack of confidence as their primary barrier to resuming sports participation is unknown. Purpose: To compare physical impairment, functional, and psychosocial measures between subgroups based on return-to-sport status and fear of reinjury/lack of confidence in the return-to-sport stage and to determine the association of physical impairment and psychosocial measures with function for each subgroup at 6 months and 1 year after surgery. Study Design: Case-control study; Level of evidence, 3. Methods: Physical impairment (quadriceps index [QI], quadriceps strength/body weight [QSBW], hamstring: quadriceps strength ratio [HQ ratio], pain intensity), self-report of function (International Knee Documentation Committee [IKDC]), and psychosocial (Tampa Scale for Kinesiophobia-shortened form [TSK-11]) measures were collected at 6 months and 1 year after surgery in 73 patients with ACL reconstruction. At 1 year, subjects were divided into "return-to-sport" (YRTS) or "not return-to-sport" (NRTS) subgroups based on their self-reported return to preinjury sport status. Patients in the NRTS subgroup were subcategorized as NRTS-Fear/Confidence if fear of reinjury/lack of confidence was the primary reason for not returning to sports, and all others were categorized as NRTS-Other. Results: A total of 46 subjects were assigned to YRTS, 13 to NRTS-Other, and 14 to NRTS-Fear/Confidence. Compared with the YRTS subgroup, the NRTS-Fear/Confidence subgroup was older and had lower QSBW, lower IKDC score, and higher TSK-11 score at 6 months and 1 year; however, they had similar pain levels. In the NRTS-Fear/Confidence subgroup, the IKDC score was associated with QSBW and pain at 6 months and QSBW, QI, pain, and TSK-11 scores at 1 year. Conclusion: Elevated pain-related fear of movement/reinjury, quadriceps weakness, and reduced IKDC score distinguish patients who are unable to return to preinjury sports participation because of fear of reinjury/lack of confidence. Despite low average pain ratings, fear of pain may influence function in this subgroup. Assessment of fear of reinjury, quadriceps strength, and self-reported function at 6 months may help identify patients at risk for not returning to sports at 1 year and should be considered for inclusion in return-to-sport guidelines.