The Effect of Ligament Modeling Technique on Knee Joint Kinematics: A Finite Element Study

Abstract

Finite element (FE) analysis has become an increasingly popular technique in the study of human joint biomechanics, as it allows for detailed analysis of the joint/tissue behavior under complex, clinically relevant loading conditions. A wide variety of modeling techniques have been utilized to model knee joint ligaments. However, the effect of a selected constitutive model to simulate the ligaments on knee kinematics remains unclear. The purpose of the current study was to determine the effect of two most common techniques utilized to model knee ligaments on joint kinematics under functional loading conditions. We hypothesized that anatomic representations of the knee ligaments with anisotropic hyperelastic properties will result in more realistic kinematics. A previously developed, extensively validated anatomic FE model of the knee developed from a healthy, young female athlete was used. FE models with 3D anatomic and simplified uniaxial representations of main knee ligaments were used to simulate four functional loading conditions. Model predictions of tibiofemoral joint kinematics were compared to experimental measures. Results demonstrated the ability of the anatomic representation of the knee ligaments (3D geometry along with anisotropic hyperelastic material) in more physiologic prediction of the human knee motion with strong correlation (r ≥ 0.9 for all comparisons) and minimum deviation (0.9º ≤ RMSE ≤ 2.29°) from experimental findings. In contrast, non-physiologic uniaxial elastic representation of the ligaments resulted in lower correlations (r ≤ 0.6 for all comparisons) and substantially higher deviation (2.6° ≤ RMSE ≤ 4.2°) from experimental results. Findings of the current study support our hypothesis and highlight the critical role of soft tissue modeling technique on the resultant FE predicted joint kinematics.

Finite Element Model of the Knee for Investigation of Injury Mechanisms: Development and Validation

“…Remaining soft tissues of the knee joint, including joint capsule, tibiofemoral and patellofemoral ligaments, and trans-knee muscle-tendon units were incorporated into the FE model as uniaxial truss elements. Considering ligaments as primary constraints to define knee joint motion, FE predicted kinematics and resulting stress/strain distributions across knee structures may be highly dependent on the modeling technique and constitutive model chosen to simulate ligamentous structures [43].…”

“…An anatomically accurate FE model of the lower extremity was developed based on the imaging data obtained from a healthy, skeletally mature young female athlete with no history of knee injury [43]. The model includes bony structures of the lower extremity in addition to soft tissue details of patellofemoral and tibiofemoral aspects of the knee joint.…”

Preferential Loading of the ACL Compared With the MCL During Landing

“…The model was extensively validated against cadaveric measurements of tibiofemoral kinematics, ACL and MCL strains, and tibiofemoral cartilage pressure over a wide range of quasistatic and dynamic loading conditions. 17 Details of the model are described by Kiapour et al 17 To better interpret experimental findings, parametric FE analyses were conducted over continuous ranges of knee abduction (0-150 N·m) and internal tibial rotation (0-100 N·m) moments in the presence of 268 N of anterior tibial shear force and simulated muscle forces (quadriceps, 1200 N; hamstring, 800 N).…”

Timing sequence of multi-planar knee kinematics revealed by physiologic cadaveric simulation of landing: Implications for ACL injury mechanism

“…Despite considerable efforts to characterize ACL injury mechanisms (Ford et al, 2003, Griffin et al, 2000, Krosshaug et al, 2007, Hewett et al, 2005, Agel et al, 2005, Arendt and Dick, 1995, Boden et al, 2000, Chappell et al, 2002, Decker et al, 2003, Hewett et al, 1999, Joseph et al, 2011, Koga et al, 2010, Malone et al, 1993, Moran and Marshall, 2006, Olsen et al, 2004, Kiapour et al, 2013a, Kiapour et al, 2013b), the relative contribution of each loading axis in the multi-axial (multi-planar) injury mechanism during landing is unclear. Due to the high-rate dynamic environment of injurious events, precise in vivo measurements of tibiofemoral joint six-degrees of freedom kinematics, its interaction with ACL tension and the associated timing sequence remain a challenge.…”