TY - JOUR
T1 - Relative Strain in the Anterior Cruciate Ligament and Medial Collateral Ligament during Simulated Jump Landing and Sidestep Cutting Tasks
T2 - Implications for Injury Risk
AU - Bates, Nathaniel A.
AU - Nesbitt, Rebecca J.
AU - Shearn, Jason T.
AU - Myer, Gregory D.
AU - Hewett, Timothy E.
N1 - Publisher Copyright:
© 2015 The Author(s).
PY - 2015/9/3
Y1 - 2015/9/3
N2 - Background: The medial collateral (MCL) and anterior cruciate ligaments (ACL) are, respectively, the primary and secondary ligamentous restraints against knee abduction, which is a component of the valgus collapse often associated with ACL rupture during athletic tasks. Despite this correlation in function, MCL ruptures occur concomitantly in only 20% to 40% of ACL injuries. Hypothesis/Purpose: The purpose of this investigation was to determine how athletic tasks load the knee joint in a manner that could lead to ACL failure without concomitant MCL failure. It was hypothesized that (1) the ACL would provide greater overall contribution to intact knee forces than the MCL during simulated motion tasks and (2) the ACL would show greater relative peak strain compared with the MCL during simulated motion tasks. Study Design: Controlled laboratory study. Methods: A 6-degrees-of-freedom robotic manipulator articulated 18 cadaveric knees through simulations of kinematics recorded from in vivo drop vertical jump and sidestep cutting tasks. Specimens were articulated in the intact-knee and isolated-ligament conditions. After simulation, each ACL and MCL was failed in uniaxial tension along its fiber orientations. Results: During a drop vertical jump simulation, the ACL experienced greater peak strain than the MCL (6.1% vs 0.4%; P <.01). The isolated ACL expressed greater peak anterior force (4.8% vs 0.3% body weight; P <.01), medial force (1.6% vs 0.4% body weight; P <.01), flexion torque (8.4 vs 0.4 N·m; P <.01), abduction torque (2.6 vs 0.3 N·m; P <.01), and adduction torque (0.5 vs 0.0 N·m; P =.03) than the isolated MCL. During failure testing, ACL specimens preferentially loaded in the anteromedial bundle failed at 637 N, while MCL failure occurred at 776 N. Conclusion: During controlled physiologic athletic tasks, the ACL provides greater contributions to knee restraint than the MCL, which is generally unstrained and minimally loaded. Clinical Relevance: Current findings support that multiplanar loading during athletic tasks preferentially loads the ACL over the MCL, leaving the ACL more susceptible to injury. An enhanced understanding of joint loading during in vivo tasks may provide insight that enhances the efficacy of injury prevention protocols.
AB - Background: The medial collateral (MCL) and anterior cruciate ligaments (ACL) are, respectively, the primary and secondary ligamentous restraints against knee abduction, which is a component of the valgus collapse often associated with ACL rupture during athletic tasks. Despite this correlation in function, MCL ruptures occur concomitantly in only 20% to 40% of ACL injuries. Hypothesis/Purpose: The purpose of this investigation was to determine how athletic tasks load the knee joint in a manner that could lead to ACL failure without concomitant MCL failure. It was hypothesized that (1) the ACL would provide greater overall contribution to intact knee forces than the MCL during simulated motion tasks and (2) the ACL would show greater relative peak strain compared with the MCL during simulated motion tasks. Study Design: Controlled laboratory study. Methods: A 6-degrees-of-freedom robotic manipulator articulated 18 cadaveric knees through simulations of kinematics recorded from in vivo drop vertical jump and sidestep cutting tasks. Specimens were articulated in the intact-knee and isolated-ligament conditions. After simulation, each ACL and MCL was failed in uniaxial tension along its fiber orientations. Results: During a drop vertical jump simulation, the ACL experienced greater peak strain than the MCL (6.1% vs 0.4%; P <.01). The isolated ACL expressed greater peak anterior force (4.8% vs 0.3% body weight; P <.01), medial force (1.6% vs 0.4% body weight; P <.01), flexion torque (8.4 vs 0.4 N·m; P <.01), abduction torque (2.6 vs 0.3 N·m; P <.01), and adduction torque (0.5 vs 0.0 N·m; P =.03) than the isolated MCL. During failure testing, ACL specimens preferentially loaded in the anteromedial bundle failed at 637 N, while MCL failure occurred at 776 N. Conclusion: During controlled physiologic athletic tasks, the ACL provides greater contributions to knee restraint than the MCL, which is generally unstrained and minimally loaded. Clinical Relevance: Current findings support that multiplanar loading during athletic tasks preferentially loads the ACL over the MCL, leaving the ACL more susceptible to injury. An enhanced understanding of joint loading during in vivo tasks may provide insight that enhances the efficacy of injury prevention protocols.
KW - anterior cruciate ligament injury
KW - athletic tasks
KW - cadaveric simulation
KW - knee biomechanics
KW - medial collateral ligament
UR - http://www.scopus.com/inward/record.url?scp=84940768002&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84940768002&partnerID=8YFLogxK
U2 - 10.1177/0363546515589165
DO - 10.1177/0363546515589165
M3 - Article
C2 - 26150588
AN - SCOPUS:84940768002
SN - 0363-5465
VL - 43
SP - 2259
EP - 2269
JO - American Journal of Sports Medicine
JF - American Journal of Sports Medicine
IS - 9
ER -