Analysis of limb kinetic asymmetry during a drop vertical jump in adolescents post anterior cruciate ligament reconstruction.

BACKGROUND: Limb asymmetry after ACL reconstruction is often cited as a risk factor for ACL reinjury. We assessed ground reaction forces on each limb during a drop vertical jump, and compared kinetic symmetry between limbs in adolescents post-ACL reconstruction versus healthy controls. METHODS: Forty-four participants who underwent an ACL reconstruction (16 male/28 female, mean age 16.1 ± 1.5, mean 7.3 ± 0.9 months post-ACL reconstruction) and 34 controls (20 male/14 female, mean age 14.9 ± 1.1) completed a drop vertical jump captured on a Vicon system and Bertec force plates. Kinetic variables were calculated individually for each limb. Inter-limb asymmetry was calculated as an index between each limb (involved versus uninvolved for the ACL reconstruction group, and left versus right for controls), and was compared between groups using independent t-tests. FINDINGS: Asymmetry was significantly more pronounced in the ACL reconstruction group versus the controls for peak contact ground reaction force (11.6% vs 4.4%, p = 0.009), eccentric impulse (8.8% vs 3.8%, p = 0.009), eccentric mean force (8.0% vs 3.4%, p = 0.006), concentric peak ground reaction force (4.1% vs 0.8%, p = 0.003), concentric impulse (5.1% vs 1.1%, p = 0.001), and peak landing ground reaction force (12.7% vs 1.7%, p < 0.001). INTERPRETATION: Limb kinetic asymmetry during a drop vertical jump was more pronounced in adolescents post-ACL reconstruction versus controls for both eccentric- and concentric-phase variables, which may indicate the use of compensatory strategies to offload the post-operative limb. Targeted interventions to produce more symmetric loading and unloading during jumping tasks should be developed, tested, and monitored to determine the impact on rehabilitation programs, return-to-sport evaluations, and injury prevention outcomes.

Rapid Transition to Virtual Assessment and Treatment in an Interdisciplinary Randomized Clinical Trial for Youth With Chronic Pain: Adaptations and Implications for Future Trials.

OBJECTIVES: COVID-19 abruptly halted in-person clinical care and research requiring a shift to virtual assessment and treatment. This unexpected transition of a 2-arm randomized controlled trial (RCT) examining interdisciplinary graded exposure treatment (GET Living) compared with multidisciplinary pain management for youth with chronic pain provided an opportunity to implement the first remotely delivered exposure treatment and remotely delivered biomechanical assessment for pediatric chronic pain. Here we describe these new approaches and provide lessons learned to inform future efforts in digital health care. METHODS: A total of 68 youth (M=14.2 y; 80.9% female) were enrolled in the RCT (n=31 in-person, n=5 hybrid, n=32 virtual, n=9 withdrew). Of those withdrawn, n=3 withdrew due to COVID-19 related reasons. Some RCT elements required slight modification (eg, e-consent, actigraphy deployment, recruitment, and screening), while others were significantly altered (eg, session format and lab-based biomechanical assessment). Data from exit interviews were also examined to assess perspectives on the virtual format transition. RESULTS: Results showed an increased enrollment rate when virtual care was an option (70.7%) compared with in-person (44.3%). Equivalent rates of completion for daily assessment (in-person, 72.8%; virtual, 73.3) were also observed, and participants described enhanced experience when able to complete exercises and exposures in their home environment during session (vs. a rehabilitation gym) allowing for genuine in vivo exposures (eg, household chores, riding bicycles). DISCUSSION: Overall, our data demonstrate acceptability, feasibility, and equivalent patient engagement to virtual treatment. Novel methods implemented in this RCT can inform trial design and measures of clinical endpoints for future digital health interventions.