Cognitive-Motor Function During Jump Landings After Anterior Cruciate Ligament Reconstruction

The risk of second anterior cruciate ligament (ACL) injury remains high after ACL reconstruction (ACLR), indicating the need to improve rehabilitation and return-to-sport assessment. Because ACL injuries frequently occur in cognitively demanding situations, dual-task screening provides a promising opportunity to detect movement impairments by testing cognitive and motor skills simultaneously.

The purpose was to evaluate cognitive-motor impairments that persist after ACLR. It was hypothesized that jump landing biomechanics would be impaired in athletes with previous ACLR versus controls and that these impairments would be exacerbated when the jump landings were performed with a cognitive challenge.

Controlled laboratory study.

A total of 35 individuals who underwent primary ACLR (ACLR group) and 35 healthy controls (HC group), matched by sex, age, dominant limb, body mass index, sports activities, Tegner score, and Marx activity score, participated in this study. Participants performed jumping tasks under a variety of conditions, including with and without visual constraint, rapid decision-making, and visual-spatial challenges. Primary dependent variables included second ACL injury factors such as asymmetry of knee extensor moment at initial contact (KEM-Asym-IC). Second-level analysis focused on other variables associated with ACL loading and injury (eg, peak knee flexion angle [pKFA]). Mixed-effect models were tested for group and condition interactions as well as group and condition main effects.

A total of 35 individuals (25 women and 10 men) who underwent ACLR (ACLR group) (age, 19.9 ± 1.7 years; height, 1.7 ± 0.1 m; mass, 69.9 ± 13.1 kg; years after ACLR, 1.5 ± 0.6 years; Tegner score, 6.8 ± 1.8; and Marx score, 10.6 ± 3.8) were matched with 35 (25 women and 10 men) HC individuals (HC group) (age, 20.1 ± 1.9 years; hight, 1.7 ± 0.1 m; mass, 67.1 ± 8.4 kg; Tegner score, 6.6 ± 1.6; and Marx score, 11 ± 3.9). No significant group and condition interactions were detected. A group effect for KEM-Asym-IC (HC group, -0.005 ± 0.8 % bodyweight-height vs ACLR group, 0.43 ± 0.82 % bodyweight-height; P < .001) indicated relatively more knee extensor moment in the uninvolved limb at initial contact for the ACLR group, regardless of condition. In addition, a condition effect for pKFA indicated that both groups demonstrated decreased knee flexion in response to rapid decision-making challenges (anticipated conditions, 79°-80° vs rapid decision-making conditions, 76°-78°; P < .001).

After return-to-sport clearance, the ACLR group showed increased presence of mechanics associated with second ACL injury compared with the HC group during jump landing movements, with rapid decision-making conditions also eliciting reduced pKFA during landing for both groups.

The extent to which these multivariable outcomes may compound injury risk after ACLR requires further research to more precisely understand opportunities for neurocognitive challenges to augment ACLR return-to-sport assessment.