Iliotibial Band Autograft Provides the Fastest Recovery of Knee Extensor Mechanism Function in Pediatric Anterior Cruciate Ligament Reconstruction.

Iliotibial band autograft is an increasingly popular option for pediatric anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to compare recovery of knee extensor mechanism function among pediatric patients who underwent ACLR using iliotibial band (IT), hamstring tendon (HT), quadriceps tendon (QT), and patellar tendon (PT) autografts. One hundred forty-five pediatric athletes (76 female; age 15.0, range 7-21 years) with recent (3-18 months) unilateral ACLR performed drop-jump landing and 45° cutting with 3D motion capture. Knee extensor mechanism function (maximum knee flexion angle, maximum internal knee extensor moment, energy absorption at knee) during the loading phase (foot contact to peak knee flexion) was compared among graft types (20 IT, 29 HT, 39 QT, 57 PT) and sides (ACLR or contralateral) using linear mixed models with sex, age, and time since surgery as covariates. Overall, knee flexion was significantly lower on the operated vs. contralateral side for HT, QT, and PT during both tasks (p < 0.03). All graft types exhibited lower knee extensor moments and energy absorption on the operated side during both movements (p ≤ 0.001). Kinetic asymmetry was significantly lower for IT compared with QT and PT during both movements (p ≤ 0.005), and similar patterns were observed for HT vs. QT and PT (p ≤ 0.07). Asymmetry was similar between IT and HT and between QT and PT. This study found that knee extensor mechanism function recovers fastest in pediatric ACLR patients with IT autografts, followed by HT, in comparison to QT and PT, suggesting that IT is a viable option for returning young athletes to play after ACLR.

Movement variability in pre-teen and teenage athletes performing sports related tasks.

BACKGROUND: Understanding movement variability is important to guide biomechanical assessment. Variability may change with age, and more repetitions of a movement need to be assessed when variability is high. RESEARCH QUESTION: This study quantified the trial-to-trial (within subject) variability of three tasks commonly assessed during sports biomechanical testing: vertical drop jump, heel touch (single leg squat from step), and single leg hop. We hypothesized that pre-teen athletes would exhibit greater variability than more mature teenage athletes when performing all of these movements. METHODS: Fifty-five uninjured pediatric athletes ages 7-15 years performed 3 repetitions of vertical drop jump, heel touch, and single leg hop for distance tasks during 3D motion analysis testing. Trial-to-trial variability was assessed using the standard deviation (SD) and range (maximum-minimum) of clinically relevant kinematic and kinetic metrics among the multiple repetitions of each task performed by each participant. Variability was compared between age groups using 2-sided t-tests. Standard error of measurement (SEM) and minimum detectable difference (MDD) were also calculated for each variable of interest. RESULTS: For drop jump and heel touch, kinetic variability was similar between groups, but the younger group had greater kinematic variability. However, the older group was much more variable than the younger group during single leg hop landing, particularly in terms of kinetics and sagittal plane kinematics. Overall, kinematic variability had a median within-subject SD of 1-9°, median range of 2-17°, and 95th percentile for range of >15-20° for many of the variables examined. MDD was >10° for many kinematic variables, >0.2 Nm/kg for all frontal plane moments, >0.4 Nm/kg for most sagittal plane moments, and >0.5 W/kg for most energy absorption variables. SIGNIFICANCE: The high within-subject trial-to-trial variability in performing sports tasks suggests that multiple trials should be analyzed for a more complete and representative evaluation.