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

Abstract

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. The objective of this study was to determine if mechanical side-to-side asymmetries persist in contralateral pairs during in vitro simulation testing. In vivo kinematics were recorded for male and female drop vertical jump and sidestep cutting tasks. The recorded kinematics were used to robotically simulate the motions on 7 contralateral pairs of cadaveric lower extremities specimens. ACL and MCL force, torque, and strains were recorded and analyzed for differences between contralateral pairs. There was a general lack of mechanical differences between limb sides. Adduction peak torque for the male sidestep cut movement was significantly different between limb sides (p = 0.04). However, this is consistent with ACL injury mechanics in that movement in the frontal plane (abduction/adduction) increases injury risk and it is possible loading differences in this plane may have resulted from tolerances within the setup process. The findings of this study indicate that contralateral knee joints were representative of each other during biomechanical in vitro tests. In future cadaveric robotic simulations, contralateral limbs can be used interchangeably. In addition, direct comparisons of the structural behaviors of isolated conditions for contralateral knee joints can be performed.

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

“…Data from the intact knee portion of the model were analyzed across the whole population cohort; however, before analysis, data points from each contralateral pair were averaged so that the contralateral pairs would not have a weighted effect on calculations. Averaging contralateral pairs was justified because contralateral limbs express a lack of mechanical differences in robotic simulations [4]. For the isolated ligament portion of the model, ACL and MCL groups were compared as randomized previously.…”

Prospective Frontal Plane Angles Used to Predict ACL Strain and Identify Those at High Risk for Sports-Related ACL Injury

“…[15][16][17]44,47 Specifically, KAM applied to the knee during multiple simulations of athletic tasks has been shown to induce greater increases in peak ACL strain than has either anterior tibial translation or internal tibial rotation torque. 7,[9][10][11][12]14,15,48,63 Along with KAM, knee abduction angle (KAA) is also associated with dynamic athletic tasks and poor neuromuscular control, especially in female athletes. 29,31 Indeed, female athletes who have gone on to develop ACL injury have exhibited greater KAA at initial contact (IC) during landing than have healthy controls.…”

“… 15 – 17 , 44 , 47 Specifically, KAM applied to the knee during multiple simulations of athletic tasks has been shown to induce greater increases in peak ACL strain than has either anterior tibial translation or internal tibial rotation torque. 7 , 9 – 12 , 14 , 15 , 48 , 63 …”

Deciphering the “Art” in Modeling and Simulation of the Knee Joint: Overall Strategy

“…The modeler needs to tackle many questions during the process, while accounting for the ultimate intended use of the model. While knee experimentation relies upon sample populations [30], in silico studies of the knee rely on a single or a handful of models (a few statistical shape models for population based studies are exceptions [31]) giving rise to many questions: Which knee should be modeled? What type of demographics or disease population should it represent?…”