A Numerical Simulation Approach to Studying Anterior Cruciate Ligament Strains and Internal Forces Among Young Recreational Women Performing Valgus Inducing Stop-Jump Activities

Abstract

Anterior cruciate ligament (ACL) injuries are commonly incurred by recreational and professional women athletes during non-contact jumping maneuvers in sports like basketball and volleyball, where incidences of ACL injury is more frequent to females compared to males. What remains a numerical challenge is in vivo calculation of ACL strain and internal force. This study investigated effects of increasing stop-jump height on neuromuscular and bio-mechanical properties of knee and ACL, when performed by young female recreational athletes. The underlying hypothesis is increasing stop-jump (platform) height increases knee valgus angles and external moments which also increases ACL strain and internal force. Using numerical analysis tools comprised of Inverse Kinematics, Computed Muscle Control and Forward Dynamics, a novel approach is presented for computing ACL strain and internal force based on (1) knee joint kinematics and (2) optimization of muscle activation, with ACL insertion into musculoskeletal model. Results showed increases in knee valgus external moments and angles with increasing stop-jump height. Increase in stop-jump height from 30 to 50 cm lead to increase in average peak valgus external moment from 40.5 ± 3.2 to 43.2 ± 3.7 Nm which was co-incidental with increase in average peak ACL strain, from 9.3 ± 3.1 to 13.7 ± 1.1%, and average peak ACL internal force, from 1056.1 ± 71.4 to 1165.4 ± 123.8 N for the right side with comparable increases in the left. In effect this study demonstrates a technique for estimating dynamic changes to knee and ACL variables by conducting musculoskeletal simulation on motion analysis data, collected from actual stop-jump tasks performed by young recreational women athletes.

The influence of muscle-tendon forces on ACL loading during jump landing: a systematic review

“…plexities have been developed, either alongside cadaveric testing to extend the experimental results 23,[33][34][35][36] , or in combination with in vivo measurements of joint kinematics, external ground reaction forces and muscle-tendon forces to investigate the factors contributing to ACL loading during jump landing 11,[37][38][39][40][41] .…”

“…This finding is in line with the in vitro results by Withrow et al 26 , who reported reduced peak AM-ACL strain with increased passive stiffness of the hamstrings, suggesting that greater hip flexion during landing may help to increase the muscles' force generating capacity to reduce anterior shear forces, and thus contribute to reduced ACL loading. Most computational models represented the ACL ligament as a straight-line 1D segment with pre-defined, non-linear elastic material properties with its insertion sites based on cadaveric measurements 11,23,[37][38][39] . In a computationally more involved approach, Kiapour et al 33 developed an anatomically-based Finite Element (FE) model of the knee joint based on CT/MRI images of one female athlete (25 years old).…”

“…Here, the open-source musculoskeletal modelling software OpenSim 42 was used in three studies to derive the muscle-tendon forces during landing based on in vivo kinematic, kinetic and EMG data, whereby one study adopted an algorithm based on static optimisation 39 while two studies deployed an advanced algorithm called computed muscle control 11,38 . In comparison to the standardised position of the knee joint and constant pre-tension of muscles (H:Q ratio) for in vitro studies, the reported muscle-tendon forces and knee joint kinematics from in situ computational modelling varied significantly between studies (Tab.…”

“…IV), with the H:Q ratio prior to impact ranging from 0.33 to 1.33, the initial knee flexion angle from 9° to 34° and the peak VIF from 1.8 to 4.1 times Body Weight (BW). Furthermore, computational simulations were often driven by in vivo data from optical motion capture, ground reaction force measurements and EMG 11,37,39,40 . Here, differences between subjects, testing procedures and data processing likely contributed to the larger range of input parameters compared to cadaveric testing.…”

“…Thereby, the ratio between the hamstrings and the quadriceps muscle-tendon force (H:Q ratio) may be related to the magnitude of ACL loading during landing. In particular, it has been previously proposed that lower H:Q ratios may lead to reduced knee stability that is associated with higher ACL strains 11 . However, such hypotheses are largely based on results from epidemiological or modelling studies; and speculation remains as to how the complex interactions of lower limb motion, muscle-tendon forces and moments influence ACL loading during high-impact dynamic situations in vivo.…”