Development and validation of a kinematically-driven discrete element model of the patellofemoral joint

Abstract

Quantifying the complex loads at the patellofemoral joint (PFJ) is vital to understanding the development of PFJ pain and osteoarthritis. Discrete element analysis (DEA) is a computationally efficient method to estimate cartilage contact stresses with potential application at the PFJ to better understand PFJ mechanics. The current study validated a DEA modeling framework driven by PFJ kinematics to predict experimentally-measured PFJ contact stress distributions. Two cadaveric knee specimens underwent quadriceps muscle [215 N] and joint compression [350 N] forces at ten discrete knee positions representing PFJ positions during early gait, while measured PFJ kinematics were used to drive specimen-specific DEA models. DEA-computed contact area and stress were compared to experimentally-measured data. There was good agreement between computed and measured mean and peak stress across the specimens and positions (r = 0.63-0.85). DEA-computed mean stress was within an average of 12% (range: 1-47%) of the experimentally-measured mean stress while DEA-computed peak stress was within an average of 22% (range: 1-40%). Stress magnitudes were within the ranges measured (0.17-1.26 MPa computationally vs 0.12-1.13 MPa experimentally). DEA-computed areas overestimated measured areas (average error = 60%; range: 4-117%) with magnitudes ranging from 139-307 mm 2 computationally vs 74-194 mm 2 experimentally. DEA estimates of the ratio of lateral to medial patellofemoral stress distribution predicted the experimental data well (mean error = 15%

Accurate Arthroscopic Cam Resection Normalizes Contact Stresses in Patients With Femoroacetabular Impingement

“…DEA is a computationally efficient tool compared with FEA and has gained popularity for numerous clinical and personalized applications because of its computational advantages and simplicity. 1,12,21,29 DEA has been previously validated against FEA for studies on hip contact stresses and was shown to be a computationally efficient and reliable alternative. 1 In the current application, the basic element is a springresisting compressive force.…”

The non-invasive evaluation technique of patellofemoral joint stress: a systematic literature review

“…FEA and DEA are refined computational models that allow the integration of subject-specific musculoskeletal parameters and experimental data, and are of great value for understanding stress distributions in complex biological structures ( Fernandez et al, 2008 ; Farrokhi et al, 2011b ; Gustafson et al, 2019 ). The researchers believe that shear stress is related to cartilage degeneration and damage, and higher shear stress in cartilage may also be the cause of damage to the exciting nociceptors present in the subchondral bone plate of the patella ( Wojtys et al, 1990 ; ( Besier et al, 2008 ).…”

Expediting Finite Element Analyses for Subject-Specific Studies of Knee Osteoarthritis: A Literature Review

“…These studies highlight that this method works rapidly compared to FEA, although the range of movement is limited to the sagittal plane and the articular cartilage is modeled as an isotropic linear elastic material. Similarly, discrete element analysis (DEA) has been utilized to model hip and knee joint contacts [198][199][200]. DEA demonstrated a similar contact response compared to FEA models of the hip joint [199], and similar contact pressure distributions to experimental measurements in the PFJ [198].…”

“…Similarly, discrete element analysis (DEA) has been utilized to model hip and knee joint contacts [198][199][200]. DEA demonstrated a similar contact response compared to FEA models of the hip joint [199], and similar contact pressure distributions to experimental measurements in the PFJ [198]. DEA does not require a volumetric mesh, using shell elements instead, with which elastic springs are associated, relating to the thickness of tissue (cartilage) and elastic properties (Young modulus and Poisson ratio).…”