Non-knee-spanning muscles contribute to tibiofemoral shear as well as valgus and rotational joint reaction moments during unanticipated sidestep cutting

Abstract

Anterior cruciate ligament (ACL) injuries are a burdensome condition due to potential surgical requirements and increased risk of long term debilitation. Previous studies indicate that muscle forces play an important role in the development of ligamentous loading, yet these studies have typically used cadaveric models considering only the knee-spanning quadriceps, hamstrings and gastrocnemius muscle groups. Using a musculoskeletal modelling approach, we investigated how lower-limb muscles produce and oppose key tibiofemoral reaction forces and moments during the weight acceptance phase of unanticipated sidestep cutting. Muscles capable of opposing (or controlling the magnitude of) the anterior shear force and the external valgus moment at the knee are thought to be have the greatest potential for protecting the anterior cruciate ligament from injury. We found the best muscles for generating posterior shear to be the soleus, biceps femoris long head and medial hamstrings, providing up to 173N, 111N and 77N of force directly opposing the anterior shear force. The valgus moment was primarily opposed by the gluteus medius, gluteus maximus and piriformis, with these muscles providing contributions of up to 32 Nm, 19 Nm and 21 Nm towards a knee varus moment, respectively. Our findings highlight key muscle targets for ACL preventative and rehabilitative interventions.

Muscle contributions to tibiofemoral shear forces and valgus and rotational joint moments during single leg drop landing

“…After completion of the maximum voluntary contractions, 43 retroreflective markers (14 mm) were affixed to various anatomical locations on the whole body as previously described. 13,16 Each participant completed a single-leg drop landing task on their right leg. Prior to performing this task, participants completed bilateral drop jump and single-leg drop landing tasks in order to prepare and familiarize themselves with the experimental procedures.…”

“…Eight recreationally active healthy males (age: 27 ± 4 years; height: 1.77 ± 0.09 m; mass: 78 ± 13 kg) volunteered to participate in this study, which formed part of a larger project investigating high-impact dynamic tasks. 13,15,16 All participants had no current or previous musculoskeletal injury likely to influence their ability to perform the required tasks. All participants provided written informed consent to participate in the study.…”

“…7 We restricted our analysis to the landing phase (defined as the time period from initial contact to peak knee flexion) because ACL injury typically occurs promptly after initial contact. 10 Muscle contributions were grouped according to functional groups similar to prior work 13 (see Table S1 for full details). Note that we focused our reporting on major muscle groups and did not report on any muscle that was not found to make a meaningful contribution to any of the three key knee joint reaction forces or moments (see Rajagopal et al 18 for all musculotendinous actuators included in the model).…”

“…For example, our previous work investigating unanticipated sidestep cutting has demonstrated the importance of the soleus for opposing the anterior shear force and the gluteus medius for opposing the valgus moment. 13 Since the way in which a muscle induces reaction forces is dependent on the kinematics of all segments in the system, 12 it is likely that muscle force contributions to knee joint loading are task specific. It may not be appropriate to infer the role of specific muscles from unanticipated sidestep cutting to other key injurious maneuvers, such as single-leg landing.…”

“…Specifically, we used an electromyography (EMG) informed neuromusculoskeletal modeling approach to predict lower-limb muscle contributions to the antero-posterior shear joint reaction force as well as the valgus/varus and internal/external rotation joint reaction moments at the knee. Based on prior work, 13,14 we hypothesized that the anterior shear force would be primarily opposed by the hamstrings and soleus, while the valgus moment would be primarily opposed by the gluteus medius.…”