title: Strain Response of the Anterior Cruciate Ligament to Uniplanar and Multiplanar Loads During Simulated Landings: Implications for Injury Mechanism.
abstract: Despite basic characterization of the loading factors that strain the anterior cruciate ligament (ACL), the interrelationship(s) and additive nature of these loads that occur during noncontact ACL injuries remain incompletely characterized.
  
  
  
  In the presence of an impulsive axial compression, simulating vertical ground-reaction force during landing (1) both knee abduction and internal tibial rotation moments would result in increased peak ACL strain, and (2) a combined multiplanar loading condition, including both knee abduction and internal tibial rotation moments, would increase the peak ACL strain to levels greater than those under uniplanar loading modes alone.
  
  
  
  Controlled laboratory study.
  
  
  
  A cadaveric model of landing was used to simulate dynamic landings during a jump in 17 cadaveric lower extremities (age, 45 ± 7 years; 9 female and 8 male). Peak ACL strain was measured in situ and characterized under impulsive axial compression and simulated muscle forces (baseline) followed by addition of anterior tibial shear, knee abduction, and internal tibial rotation loads in both uni- and multiplanar modes, simulating a broad range of landing conditions. The associations between knee rotational kinematics and peak ACL strain levels were further investigated to determine the potential noncontact injury mechanism.
  
  
  
  Externally applied loads, under both uni- and multiplanar conditions, resulted in consistent increases in peak ACL strain compared with the baseline during simulated landings (by up to 3.5-fold; P ≤ .032). Combined multiplanar loading resulted in the greatest increases in peak ACL strain (P < .001). Degrees of knee abduction rotation (R(2) = 0.45; β = 0.42) and internal tibial rotation (R(2) = 0.32; β = 0.23) were both significantly correlated with peak ACL strain (P < .001). However, changes in knee abduction rotation had a significantly greater effect size on peak ACL strain levels than did internal tibial rotation (by ~2-fold; P < .001).
  
  
  
  In the presence of impulsive axial compression, the combination of anterior tibial shear force, knee abduction, and internal tibial rotation moments significantly increases ACL strain, which could result in ACL failure. These findings support multiplanar knee valgus collapse as one the primary mechanisms of noncontact ACL injuries during landing.
  
  
  
  Intervention programs that address multiple planes of loading may decrease the risk of ACL injury and the devastating consequences of posttraumatic knee osteoarthritis.
authors.affiliation: Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, USA Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Orthopaedics and Bioengineering, University of Toledo, Toledo, Ohio, USA.
authors.forename: Ata M
authors.initials: AM
authors.lastname: Kiapour
authors.affiliation: Biomechanics & Injury Mitigation Systems, Research & Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA.
authors.forename: Constantine K
authors.initials: CK
authors.lastname: Demetropoulos
authors.affiliation: Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Orthopaedics and Bioengineering, University of Toledo, Toledo, Ohio, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Kiapour
authors.affiliation: Sports Health and Performance Institute, The Ohio State University, Columbus, Ohio, USA Department of Orthopaedic Surgery, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Carmen E
authors.initials: CE
authors.lastname: Quatman
authors.affiliation: Sports Health and Performance Institute, The Ohio State University, Columbus, Ohio, USA Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Wordeman
authors.affiliation: Engineering Center for Orthopaedic Research Excellence (ECORE), Departments of Orthopaedics and Bioengineering, University of Toledo, Toledo, Ohio, USA.
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Goel
authors.affiliation: Mayo Biomechanics Laboratories, Mayo Sports Medicine Center, Departments of Orthopedic Surgery, Physical Medicine & Rehabilitation, and Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA Hewett.Timothy@mayo.edu.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Hewett
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000502:physiology / Q000503:physiopathology*; D000070598:Anterior Cruciate Ligament Injuries / Q000150:complications / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007717:Knee / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000209:etiology; D059385:Plyometric Exercise; D011312:Pressure; D012399:Rotation; D013977:Tibia / Q000502:physiology
keywords: ACL; anterior cruciate ligament; injury mechanism; knee; landing; multiplanar valgus collapse