Altered lower extremity biomechanics following anterior cruciate ligament reconstruction during single-leg and double-leg stop-jump tasks: A bilateral total support moment analysis

Joint contributions to sagittal plane total support moment in patients with knee osteoarthritis after anterior cruciate ligament reconstruction

BACKGROUND

Patients with anterior cruciate ligament reconstruction (ACLR) demonstrate lower knee loading. This study aimed to determine whether sagittal plane TSM and joint contributions to total support moment (TSM) in the surgical limb are different between athletes who did and did not show radiological features of knee OA at 2 years after ACLR during triple hops (TH), single hop (TH), single-legged vertical jump (VJ), and walking.

METHODS

Forty-one athletes with 2 years of unilateral ACLR surgery participated in this cross-sectional study. Athletes completed motion analysis testing of single-legged TH, SH, VJ, and walking tasks. Sagittal plane TSM and individual joint (ankle, knee, and hip) contributions to TSM were computed at peak knee flexion angle (TSM-PKF). Posterior-anterior radiographs were completed in standing and 30° knee flexion. Kellgren-Lawrence (KL) system was used to identify radiological features of knee OA in the medial compartment of the reconstructed knee (OA-group: KL ≥2; Non-OA group: KL<2).

RESULTS

There was a significant group-by-joint-by-task interaction for joint contributions to TSM-PKF (p = 0.012), with the OA-group (n = 13) had lower knee and higher hip contributions compared to the non-OA group during TH, SH, and VJ (p ≤ 0.049). There was a significant joint-by-group interaction for the joint contributions to TSM-PKF (p = 0.004), with the OA-group having lower knee (p = 0.003) and higher hip (p = 0.001) contributions compared to the Non-OA group.

SIGNIFICANCE

The OA-group exhibited lower knee and higher hip contributions to the sagittal plane TSM compared to the Non-OA group during the landing phase of single-limb high-demand activities. The OA-group exhibited decreased knee loading and compensated by shifting the mechanical load to the hip joint within the reconstructed knee. Decreased knee loading in the OA-group may have affected the required mechanical loading to maintain knee metabolism and integrity.

Knee Kinetics and Kinematics of Young Asymptomatic Participants during Single-Leg Weight-Bearing Tasks: Task and Sex Comparison of a Cross-Sectional Study

This cross-sectional study aimed to describe and compare kinetic and kinematic variables of the knee joint during stair descent, single-leg step down, and single-leg squat tasks. It also aimed to investigate potential sex difference during the tasks. Thirty young asymptomatic individuals (15 males, 15 females) were assessed during the performance of single-leg weight-bearing tasks. The kinetic and kinematic data from the knee were evaluated at the peak knee moment and at peak knee flexion. Single-leg squat presented a higher peak knee moment (2.37 Nm/kg) and the greatest knee moment (1.91 Nm/kg) at knee peak angle in the frontal plane, but the lowest knee flexion (67°) than the other two tasks (p < 0.05). Additionally, the single-leg step down task presented a higher varus knee angle (5.70°) when compared to stair descent (3.71°) (p < 0.001). No substantial sex difference could be observed. In conclusion, in asymptomatic young individuals, single-leg squats presented the greatest demand in the frontal and sagittal planes. Single-leg step down demanded a greater angular displacement than stair descent in the frontal plane. We did not identify a significant difference among the sex and studied variables.