Valgus Plus Internal Rotation Moments Increase Anterior Cruciate Ligament Strain More Than Either Alone

Department of Mechanical Engineering, Sogang University, Seoul, Republic of Korea.
Medicine and science in sports and exercise (Impact Factor: 3.98). 08/2011; 43(8):1484-91. DOI: 10.1249/MSS.0b013e31820f8395
Source: PubMed


To test the influence of combined knee valgus and internal tibial rotation moment on anterior cruciate ligament (ACL) strain during single-leg landing. We tested the following hypotheses: the combination of the valgus and internal rotation moments observed during single-leg landing produces a higher ACL strain than either moment applied individually, the combined rotational moments at the physiological levels observed could theoretically increase strain in the ACL high enough to rupture the ACL, and the location of the peak contact force was at the posterior-lateral side for combined loading.
The study was conducted by applying in vivo human loading data to a validated simulation model of the three-dimensional dynamic knee joint to predict ACL strains.
The peak ACL strain increased nonlinearly when either applied valgus moment or internal rotation moment was increased in the model. When the two rotational moments were applied individually, neither caused ACL strain >0.077. However, when applied in combination, the two rotational moments had a much larger effect, and the predicted peak ACL strain increased up to 0.105. During landing, the peak contact force occurred at the posterior-lateral side of the tibial cartilage in the model when the combined maximum valgus moment and tibial internal rotation moments were applied.
Combined knee valgus and internal rotation moments increases ACL strain more than either alone. The combination of a valgus and internal rotational moment at magnitudes that occurs in vivo during landing can cause ACL strains that may be high enough to cause ACL rupture. This predicted high ACL strain and the contact force location suggest that combined valgus and internal tibial rotational moments during single-leg landing are relevant to ACL injuries.

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    • "The ACL force also increased that is likely due to the substantial drop in lateral hamstrings activity despite a smaller drop in quadriceps activity. Force in ACL also increased as adduction rotation decreased (R À 1.5) that is likely due to higher quadriceps activity (Mesfar and Shirazi-Adl, 2005; Shin et al., 2011). Increases in ACL and LCL forces with the adduction rotation "
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    ABSTRACT: Medial knee osteoarthritis is a debilitating disease. Surgical and conservative interventions are performed to manage its progression via reduction of load on the medial compartment or equivalently its surrogate measure, the external adduction moment. However, some studies have questioned a correlation between the medial load and adduction moment. Using a musculoskeletal model of the lower extremity driven by kinematics-kinetics of asymptomatic subjects at gait midstance, we aim here to quantify the relative effects of changes in the knee adduction angle versus changes in the adduction moment on the joint response and medial/lateral load partitioning. The reference adduction rotation of 1.6° is altered by ±1.5° to 3.1° and 0.1° or the knee reference adduction moment of 17Nm is varied by ±50% to 25.5Nm and 8.5Nm. Quadriceps, hamstrings and tibiofemoral contact forces substantially increased as adduction angle dropped and diminished as it increased. The medial/lateral ratio of contact forces slightly altered by changes in the adduction moment but a larger adduction rotation hugely increased this ratio from 8.8 to a 90 while in contrast a smaller adduction rotation yielded a more uniform distribution. If the aim in an intervention is to diminish the medial contact force and medial/lateral load ratio, a drop of 1.5° in adduction angle is much more effective (causing respectively 12% and 80% decreases) than a reduction of 50% in the adduction moment (causing respectively 4% and 13% decreases). Substantial role of changes in adduction angle is due to the associated alterations in joint nonlinear passive resistance. These findings explain the poor correlation between knee adduction moment and tibiofemoral compartment loading during gait suggesting that the internal load partitioning is dictated by the joint adduction angle.
    Journal of Biomechanics 03/2014; 47(7). DOI:10.1016/j.jbiomech.2014.02.028 · 2.75 Impact Factor
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    • "Jump landings produce high, sudden ground reaction forces that translate into large external torques at the knee that can rupture the ACL (Boden et al., 2000; Hewett et al., 1999). Research with threedimensional motion capture systems has identified a number of mechanical factors that contribute to ACL injury risk during athletic tasks such as excessive knee abduction (Ford et al., 2003; Hewett et al., 2005), knee compression forces (Fleming et al., 2001; Meyer and Haut, 2008), internal tibial rotation (Meyer and Haut, 2008; Shin et al., 2011), and insufficient hip and knee flexion (Chappell and Limpisvasti, 2008; Pollard et al., 2010). The prevalence of these mechanical variables during athletic tasks can be attributed to an athlete's level of neuromuscular control (Hewett et al., 2005). "
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    Clinical biomechanics (Bristol, Avon) 04/2013; 28(4). DOI:10.1016/j.clinbiomech.2013.02.013 · 1.97 Impact Factor
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    • "Even though, a reduction in hamstrings EMG activity while sliding, as well as increased knee extension and abduction moments were found. These biomechanical alterations have been previously related to knee injuries in recreational sports practitioners and athletes, and verified in different experimental protocols [54]–[56]. It is believed that reduced hamstrings activation during knee extension may expose the ligamentous structures to higher anterior shear forces, increasing risk of sustaining injuries such as ACL ruptures [6], [12]. "
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    PLoS ONE 03/2013; 8(3):e59029. DOI:10.1371/journal.pone.0059029 · 3.23 Impact Factor
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