Background:Anterior vertebral body tethering (AVBT) for adolescent idiopathic scoliosis (AIS) is postulated to preserve motion compared with traditional posterior spinal fusion (PSF), but few studies exist to date. We used a validated computerized 3D model to compare trunk motion between patients treated with PSF and AVBT, and analyzed trunk motion in relation to the lowest instrumented vertebra (LIV).Methods:This was a single-center retrospective review of a consecutive series of skeletally immature patients with AIS who underwent motion analysis prior to PSF (n = 47) or AVBT (n = 65) and 2 years postoperatively. Patients were divided into 4 groups on the basis of the LIV (≤L1, L2, L3, L4). Computerized 3D kinematic evaluations included thoracic and lumbar flexion, extension, side-bending, and rotation. Patient outcomes were assessed using the Scoliosis Research Society (SRS)-22 questionnaire.Results:The LIV was ≤L1 in 48 patients treated with AVBT and 23 treated with PSF, L2 in 4 AVBT and 8 PSF patients, L3 in 10 AVBT and 8 PSF patients, and L4 in 3 AVBT and 8 PSF patients. PSF patients had a significant loss of motion in all 4 directions at 2 years postoperatively (e.g., flexion loss was 11° for ≤L1 to 30° for L4; p < 0.001). This equated to a 7° loss of trunk flexion per additional LIV level included in the fusion. AVBT patients only demonstrated loss of flexion and side-bending at 2 years postoperatively (e.g., flexion loss of 11° for L1 to 17° for L4; p < 0.001). Preoperative curve size and flexibility did not have any significant impact on differences in trunk motion between AVBT and PSF. SRS-22 scores were predominantly similar for AVBT versus PSF preoperatively and at 2 years postoperatively.Conclusions:Patients treated with AVBT experienced predominantly less motion loss compared with PSF patients at 2 years postoperatively. Patients treated with PSF demonstrated loss of motion in all planes that increased with each additional LIV from ≤L1 to L4, with 7° loss of flexion per additional LIV. However, the differences in total trunk motions were relatively modest for PSF and AVBT with an LIV of ≤L1. Preoperative curve magnitude and flexibility had no significant impact on trunk motion in either group. SRS-22 scores were similar for both groups at 2 years postoperatively.Level of Evidence:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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Background: Motion capture has become increasingly recognized as an important evaluation tool for guiding rehabilitation planning and in determining when it is safe to return to sport. To ensure motion capture utility in sports evaluations, it is important to establish training protocols across test centers. Hypothesis/Purpose: The purpose of this study was to evaluate the inter and intra tester reliability of return-to-sport testing using motion capture at three different motion analysis centers. Methods: A single tester and athlete traveled to three different motion analysis centers. On the first day, the first tester demonstrated marker placement and the execution of the six sports related tasks. The second tester completed the same protocol the same afternoon. On the following day, both testers repeated the process on the same athlete. The six tasks included the drop vertical jump (DVJ), deceleration, heel touch, lateral shuffle, 45° cut, and single leg hop. Kinematic data included trunk flexion/lean, pelvic obliquity, hip flexion/rotation/adduction, and knee valgus/flexion. Additionally, kinetics were analyzed for knee valgus moments. For each testing day, the mean, median, standard deviation, and range were calculated. To compare between days, differences between means and paired t-tests were calculated ( α=0.05). Results: Looking at inter tester reliability kinematics and kinetics, of the 48 calculated mean differences only two variables were statistically significant – DVJ moment (mean difference 0.22 Nm/kg, p=0.008) and lateral shuffle trunk flexion (mean difference 4.8 degrees, p=0.004). Looking at only the kinematic data, 95% (41/43) of the variables had mean differences that were four degrees or less. For intra tester reliability, of the 48 calculated mean differences three variables were statistically significant – DVJ knee flexion (mean difference 4.65 degrees, p=.041), DVJ trunk flexion (mean difference -3.7 degrees, p=0.03) and deceleration hip flexion (mean difference -5.71 degrees, p=0.034). Looking at only the kinematic data, all mean differences were less than 6 degrees, and 86% (37/43) were less than four degrees. Conclusion: This study demonstrates that after one training session, motion capture sports testing was remarkably consistent within and between testers at three different motion analysis centers. This strengthens the case that sports evaluations using motion capture is reproducible and can be replicated at novel centers with trained motion analysis personnel. To confirm inter and intra tester reliability, future studies should expand to more centers, additional testers, and athletes. [Table: see text]

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Anterior cruciate ligament (ACL) tears are one the most prevalent activity-related injuries among athletes in the United States. ACL reconstructive surgeries are typically done using a patellar tendon graft or hamstring tendon graft. There is debate as to which type of graft surgery is best, as surgeon preferences between the two differ. Thus, the primary aim of this pilot study was to compare the aforementioned ACL surgical techniques. A secondary aim was to provide physical therapists and patients with real-time feedback about the progress of the recovery over time when performing a common physical therapy exercise regimen.The results of this pilot study demonstrate that the surgical techniques can be evaluated using a dynamic multi-system approach. These systems include 1) a motion capture system, 2) electromyography (EMG) sensors, and 3) a force platform system. The significant parameters included knee flexion, maximum muscle activity from the muscles around the knee, and balance control variables.The results of the study revealed that when considering the knee flexion data, the hamstring graft is more beneficial than the patellar tendon graft in terms of showing progress over the course of the study. With regards to EMG and force platform results, the data proved either inconclusive or favoring the patellar tendon graft technique during the chair squat and sit to stand activities. With this research, we can conclude that real-time feedback may be a useful approach for ACL rehabilitation, and in determining which surgical approach may be most ideal for recovering patients.