The Effect of Articular Cartilage Focal Defect Size and Location in Whole Knee Biomechanics Models

Abstract

Articular cartilage focal defects are common soft tissue injuries potentially linked to osteoarthritis (OA) development. Although several defect characteristics likely contribute to osteoarthritis, their relationship to local tissue deformation remains unclear. Using finite element models with various femoral cartilage geometries, we explore how defects change cartilage deformation and joint kinematics assuming loading representative of the maximum joint compression during the stance phase of gait. We show how defects, in combination with location-dependent cartilage mechanics, alter deformation in affected and opposing cartilages, as well as joint kinematics. Small and average sized defects increased maximum compressive strains by approximately 50% and 100%, respectively, compared to healthy cartilage. Shifts in the spatial locations of maximum compressive strains of defect containing models were also observed, resulting in loading of cartilage regions with reduced initial stiffnesses supporting the new, elevated loading environments. Simulated osteoarthritis (modeled as a global reduction in mean cartilage stiffness) did not significantly alter joint kinematics, but exacerbated tissue deformation. Femoral defects were also found to affect healthy tibial cartilage deformations. Lateral femoral defects increased tibial cartilage maximum compressive strains by 25%, while small and average sized medial defects exhibited decreases of 6% and 15%, respectively, compared to healthy cartilage. Femoral defects also affected the spatial distributions of deformation across the articular surfaces. These deviations are especially meaningful in the context of cartilage with location-dependent mechanics, leading to increases in peak contact stresses supported by the cartilage of between 11% and 34% over healthy cartilage.

Clinical Application of the Basic Science of Articular Cartilage Pathology and Treatment

“…10 Compressive strains can increase between 50 and 100%, depending on defect size and location. 11 Regardless of location of the defect within the joint, the general cascade of events follows a similar pathway of cell phenotype alterations, necrosis, and/or apoptosis; proteoglycan and collagen disruption, alteration and loss; inflammation; degradation; and remodeling regardless of etiology. However, the timing, order, and severity of responses can vary greatly.…”

The Biomechanical Influence of Defected Cartilage on the Progression of Osteochondral Lesions of the Talus: A Three‐dimensional Finite Element Analysis

“…9 The increase in local mechanical stress near the edge of the defect area may herald a potential mechanical overload of cells near the damaged tissue. 10 Conventional biomechanical experiments insufficiently shed light on the biomechanical features of articular cartilage to assist clinical treatment. 11 Hunt et al's experimental study 9 using cadaveric ankle joints found a high-stress presence near the rim of defect cartilages when the defect sizes reached 10 mm and above.…”

Influence of material heterogeneity on the mechanical response of articulated cartilages in a knee joint

“…Although many studies were conducted on the articular cartilage behavior with multiple constitutive models, 37–42 the mechanical response of heterogeneous cartilage at maximum loading position in a gait is not adequately compared. Therefore, our primary objective is to address this issue by considering graded cartilage material with multiple heterogeneous constitutive models.…”

“…33 The highly heterogeneous nature of superficial zone can simulate well with such models 34,35 the most influential compartment on articular cartilage to mechanical response. 36 Although many studies were conducted on the articular cartilage behavior with multiple constitutive models, [37][38][39][40][41][42] the mechanical response of heterogeneous cartilage at maximum loading position in a gait is not adequately compared. Therefore, our primary objective is to address this issue by considering graded cartilage material with multiple heterogeneous constitutive models.…”