Hamstring Tendon Autograft Is Associated With Increased Knee Valgus Moment After Anterior Cruciate Ligament Reconstruction: A Biomechanical Analysis.

BACKGROUND: There is limited evidence related to the effects of autograft type on functional performance after anterior cruciate ligament reconstruction (ACLR). PURPOSE/HYPOTHESIS: This study aimed to compare biomechanical outcomes during a drop vertical jump (DVJ) between patients with a hamstring tendon (HT) autograft, quadriceps tendon (QT) autograft with bone block, QT autograft without bone block, and bone-patellar tendon-bone autograft at 6 months postoperatively in an adolescent population. The authors' hypothesized there would be differences in DVJ biomechanics between athletes depending on the type of autograft used. STUDY DESIGN: Controlled laboratory study. METHODS: Patients aged 8 to 18 years who underwent primary ACLR were included for analysis. Kinematic and kinetic data collected during a DVJ using a 3-dimensional computerized marker system were assessed at 6 months after ACLR and compared with the uninjured contralateral limb. RESULTS: A total of 155 participants were included. There were no significant differences in terms of age, sex, or affected leg (P≥ .1973) between groups. The HT group was significantly associated with a larger knee valgus moment at initial contact compared with the QT group (28 × 10-2 vs -35 × 10-2 N·m/kg, respectively; P = .0254) and a significantly larger maximum hip adduction moment compared with the QT with bone block group (30 × 10-2 vs -4 × 10-2 N·m/kg, respectively; P = .0426). Both the QT with bone block (-12 × 10-2 vs -3 × 10-2 N·m/kg, respectively; P = .0265) and QT (-13 × 10-2 vs -3 × 10-2 N·m/kg, respectively; P = .0459) groups demonstrated significantly decreased mean knee extension moments compared with the HT group. CONCLUSION: The findings of this study suggest that utilizing an HT autograft resulted in a significantly increased knee valgus moment at initial contact compared with a QT autograft without bone block at 6 months after ACLR in adolescent patients performing a DVJ. A QT autograft was found to be associated with significantly decreased extensor mechanism function compared with an HT autograft. CLINICAL RELEVANCE: This study adds unique kinematic and kinetic information regarding various ACLR autograft options and highlights the biomechanical deficits that should be taken into consideration in rehabilitation.

Biomechanical Gender Differences in the Uninjured Extremity After Anterior Cruciate Ligament Reconstruction in Adolescent Athletes: A Retrospective Motion Analysis Study.

Introduction Subsequent anterior cruciate ligament (ACL) injury is more common in the pediatric population and encompasses graft failure and subsequent contralateral tears. Females are at a higher risk. The purpose of the present study was to compare the knee valgus angles at initial contact, knee extension moments, anterior and lateral knee joint forces, hip flexion angles, hip adduction moments, and ankle inversion during the drop vertical test in the uninjured extremity between adolescent males and females who had previously undergone an anterior cruciate ligament reconstruction (ACLR). Methods This IRB-approved retrospective chart review included patients aged 8-18 years who were seen at the five to seven month postoperatively following ACL reconstruction. A total of 168 patients met our inclusion criteria (86 girls and 82 boys.) Using three-dimensional motion capture technology (CORTEX software, Motion Analysis Corp., Rohnert Park, CA), data were collected while the subject performed the drop vertical test over floor-mounted force plates (FP-Stairs, AMTI, Watertown, MA) under the direct supervision of a pediatric physical therapist. The Wilcoxon rank sum was used, and p < 0.05 was considered statistically significant. Results Females demonstrated a larger average knee joint extension moment (0.31 vs 0.28 N*m/kg, p = 0.0408), a larger anterior knee joint force at initial contact (3.51 vs. 2.79, N/kg, p = 0.0458), larger average hip flexion angle (41.50° vs. 35.99°, p = 0.0005), a smaller maximum hip adduction moment (0.92 vs. 1.16, N*m/kg, p = 0.0497), and a smaller average ankle inversion angle (5.08° vs. 6.41°, p = 0.03231). No significant differences were found regarding knee abduction angle or lateral knee joint force. Conclusions The biomechanical profile of the contralateral extremity varies significantly between the genders after ACLR. In the uninjured extremity, females may have larger hip flexion angles, smaller hip adduction moments, larger anterior knee joint forces, larger knee extension moments, and smaller ankle inversion angles as compared to males after ACLR. These findings may explain the higher incidence of subsequent contralateral injury in female adolescent athletes. Further work is required to develop a composite score that determines at-risk athletes.

Provision of Peace and Right to Health through Sanctions: Threats and Opportunities.

According to the purposes for the formation of the United Nations, sophistication of institutions like the Security Council must be evaluated based on the provision of peace and how they guarantee human rights. Therefore, in case Security Council does not follow these two mentioned factors, its function would be itself a threat to the international peace and security. This analytical research is based on collecting library theoretical data related to different field studies which investigated the effects of sanctions issued by the Security Council, the United States and the European Union on citizens' health and tried to assess both their efficiency and legitimacy. The right to health is connected with the right of living. In case enough drugs, appropriate treatment and medical equipment are not provided at the proper time, both physical and mental health might be threatened and this can cause death of a large number of people. Considering the Security Council as an institution which is expected to take into account the citizens' basic rights and not to ignore its own initial objective, the present paper was an attempt to provide explanations for the above concepts and their relationships and to analyze the findings of previous field studies. The paper concluded that sanctions issued by the Security Council and the United States are potentially functioning as threats to the international peace and so these sanctions are violating the citizens' right to health.

A fast inverse dynamics model of walking for use in optimisation studies.

Computer simulation of human gait, based on measured motion data, is a well-established technique in biomechanics. However, optimisation studies requiring many iterative gait cycle simulations have not yet found widespread application because of their high computational cost. Therefore, a computationally efficient inverse dynamics model of 3D human gait has been designed and compared with an equivalent model, created using a commercial multi-body dynamics package. The fast inverse dynamics model described in this paper led to an eight fold increase in execution speed. Sufficient detail is provided to allow readers to implement the model themselves.