The influence of internal and external tibial rotation offsets on knee joint and ligament biomechanics during simulated athletic tasks.

Background: Following anterior cruciate ligament injury and subsequent reconstruction transverse plane tibiofemoral rotation becomes underconstrained and overconstrained, respectively. Conflicting reports exist on how rotations influence loading at the knee. This investigation aimed to determine the mechanical effects of internal and external tibial rotation offsets on knee kinematics and ligament strains during in vitro simulations of in vivo recorded kinematics.

Effects of Population Variability on Knee Loading During Simulated Human Gait.

Cadaveric simulation models allow researchers to study native tissues in situ. However, as tests are conducted using donor specimens with unmatched kinematics, techniques that impose population average motions are subject to deviation from true physiologic conditions. This study aimed to identify factors which explain the kinetic variability observed during robotic simulations of a single human gait motion using a sample of human cadaver knees.

Knee Abduction Affects Greater Magnitude of Change in ACL and MCL Strains Than Matched Internal Tibial Rotation In Vitro.

Background: Anterior cruciate ligament (ACL) injures incur over USD 2 billion in annual medical costs and prevention has become a topic of interest in biomechanics. However, literature conflicts persist over how knee rotations contribute to ACL strain and ligament injury. To maximize the efficacy of ACL injury prevention, the effects of underlying mechanics need to be better understood.

Robotic simulation of identical athletic-task kinematics on cadaveric limbs exhibits a lack of differences in knee mechanics between contralateral pairs.

Limb asymmetry is a known factor for increased ACL injury risk. These asymmetries are normally observed during in vivo testing. Prior studies have developed in vitro testing methodologies driven by in vivo kinematics to investigate knee mechanics relative to ACL injury.

Posterior Tibial Slope Angle Correlates With Peak Sagittal and Frontal Plane Knee Joint Loading During Robotic Simulations of Athletic Tasks.

Background: Tibial slope angle is a nonmodifiable risk factor for anterior cruciate ligament (ACL) injury. However, the mechanical role of varying tibial slopes during athletic tasks has yet to be clinically quantified.

Purpose: To examine the influence of posterior tibial slope on knee joint loading during controlled, in vitro simulation of the knee joint articulations during athletic tasks.

Sex-based differences in knee ligament biomechanics during robotically simulated athletic tasks.

ACL injury rates are greater in female athletes than their male counterparts. As female athletes are at increased risk, it is important to understand the underlying mechanics that contribute to this sex bias. The purpose of this investigation was to employ a robotic manipulator to simulate male and female kinematics from athletic tasks on cadaveric specimens and identify sex-based mechanical differences relative to the ACL loading.

Impacts of Robotic Compliance and Bone Bending on Simulated Knee Kinematics.

Robotic testing offers researchers the opportunity to quantify native tissue loads for the structures of the knee joint during activities of daily living. These loads may then be translated into design requirements for future treatments and procedures to combat the early onset of knee degeneration following an injury. However, high knee loads during testing have the potential to deflect a robotic end effector and cause inaccuracies in the applied kinematics.

Relative strain in the anterior cruciate ligament and medial collateral ligament during simulated jump landing and sidestep cutting tasks: implications for injury risk.

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.

A Novel Methodology for the Simulation of Athletic Tasks on Cadaveric Knee Joints with Respect to In Vivo Kinematics.

Six degree of freedom (6-DOF) robotic manipulators have simulated clinical tests and gait on cadaveric knees to examine knee biomechanics. However, these activities do not necessarily emulate the kinematics and kinetics that lead to anterior cruciate ligament (ACL) rupture. The purpose of this study was to determine the techniques needed to derive reproducible, in vitro simulations from in vivo skin-marker kinematics recorded during simulated athletic tasks.

Primary and secondary restraints of human and ovine knees for simulated in vivo gait kinematics.

Knee soft tissue structures are frequently injured, leading to the development of osteoarthritis even with treatment. Understanding how these structures contribute to knee function during activities of daily living (ADLs) is crucial in creating more effective treatments. This study was designed to determine the role of different knee structures during a simulated ADL in both human knees and ovine stifle joints.

Effect of perturbing a simulated motion on knee and anterior cruciate ligament kinetics.

Current surgical treatments for common knee injuries do not restore the normal biomechanics. Among other factors, the abnormal biomechanics increases the susceptibility to the early onset of osteoarthritis. In pursuit of improving long term outcome, investigators must understand normal knee kinematics and corresponding joint and anterior cruciate ligament (ACL) kinetics during the activities of daily living.