Association of knee extensor strength symmetry and psychological factors with single-leg hop performance differs according to recovery of knee extensor strength after anterior cruciate ligament reconstruction with hamstring autograft: A cross-sectional study.

Abstract

This study aimed to determine whether the association of knee extensor strength symmetry and psychological factors with single-leg hop distance (SLHD) differs according to recovery of knee extensor strength after anterior cruciate ligament (ACL) reconstruction with hamstring autograft. Patients who underwent primary ACL reconstruction with knee function test results at 12 months after the surgery were included. Isokinetic knee extensor strength and SLHD were assessed, and the limb symmetry index (LSI) were calculated. Tampa scale for kinesiophobia-11 (TSK-11) score and ACL-Return to Sport after Injury (ACL-RSI) score were measured as psychological factors. The patients were divided into two groups according to the LSI of knee extensor strength: at least 80 % (the High group) or less than 80 % (the Low group). Multivariable liner regression analyses were conducted with the LSI of the SLHD as dependent variable, and the LSI of knee extensor strength and the psychological factors as independent variables for the High and Low groups, respectively. Of the 251 patients, 163 patients were included in the High group, and 88 patients were included in the Low group. In the High group, the psychological factors were significantly associated with the SLHD, whereas the LSI of knee extensor strength was not associated. Conversely, in the Low group, the LSI of knee extensor strength was significantly associated with SLHD, whereas the psychological factors were not associated. The association of knee extensor strength symmetry and psychological factors with SLHD differs according to knee extensor strength recovery after ACL reconstruction.