Study design: Cross-sectional. Objectives To compare performance on the modified Star Excursion Balance Test (SEBT) between participants with anterior cruciate ligament reconstruction (ACLR) at the time of return to sport and uninjured control participants.
Background: The modified SEBT is a clinical tool to assess neuromuscular control deficits. Deficits in dynamic stability and neuromuscular control persist after ACLR, but assessment with the modified SEBT in this population at the time of return to sport has not been reported.
Methods: Sixty-six participants (mean age, 17.6 years) at the time of return to sport following unilateral primary ACLR (ACLR group) and 47 uninjured participants (mean age, 17.0 years) serving as a control group participated. For the modified SEBT, the anterior, posteromedial, and posterolateral reach distances were recorded. Lower extremity muscle strength was quantified with isokinetic dynamometry. Independent-sample t tests were used to evaluate performance differences between the ACLR group and the control group and between the ACLR subgroups. In the ACLR group, bivariate correlations determined the association of modified SEBT performance with time since surgery and lower extremity muscle strength.
Results: The ACLR group had lower anterior reach distances on the involved and uninvolved limbs compared to the control group. There were no differences observed between groups in reach distances for the posteromedial and posterolateral directions or in limb symmetry indices for any of the reach directions. In the ACLR group, time from surgery and meniscal status at the time of ACLR did not influence modified SEBT performance, whereas participants with patellar bone-tendon-bone grafts had a lower posterolateral reach distance compared to those with hamstring grafts. In the ACLR group, involved-limb hip abduction strength positively correlated with all reach distances, and quadriceps strength positively correlated with posterolateral reach.
Conclusion: At the time of return to sport, participants post-ACLR demonstrated reduced modified SEBT anterior reach in both involved and uninvolved limbs compared to uninjured participants, with no other group differences. In the ACLR group, modified SEBT reach distance was associated with lower extremity muscle strength, but not with time from reconstruction or meniscal status at the time of ACLR. Lower extremity muscle strength and graft type may interact to influence modified SEBT posterior reach performance, but this requires further study.
Level of evidence: Prognosis level 2b-.
Keywords: ACL; ACL reconstruction; dynamic stability; knee; performance.