Large population evaluation of contact stress exposure in articular joints for prediction of osteoarthritis onset and progression

“…Following validation of the custom DEA methodology, an initial series of nineteen patients was retrospectively selected for DEA assessment from a larger cohort of geometry was segmented using a custom semi-automatic technique [83]. These patientspecific models were then smoothed and aligned to the coordinate system defined by…”

Section: Previous Work and Rationalementioning

confidence: 99%

“…Computation of contact stress in the hip joint upon application of each of the three different gait cycles was completed using a DEA technique previously developed in MATLAB by Andrew Kern, PhD [83]. This method consists of two rigid contact surfaces connected by a bed of compressive springs representing locations of potential contact.…”

Section: Dea Algorithmmentioning

confidence: 99%

mentioning

confidence: 99%

“…Patient-specific geometries, material properties, and appropriate boundary conditions serve as inputs, and a Newton's iterative scheme computes the contact stress using a load control algorithm until a prescribed tolerance has been met. Image taken from Kern[83].2.6 Clinical Measures of Patient OutcomesThe future goal of this overall line of investigation is to accurately model the three-dimensional joint environment in dysplasia patients and relate the DEA-computed contact stress results with patient-reported outcomes. To assess how DEA-calculated contact stress distributions relate to short-term patient-reported outcomes, VAS, WOMAC, and SF-36 outcome measures were extracted for each of the dysplasia patients in our analysis before PAO and at an average of 2.5±1.9 years following PAO.…”

mentioning

confidence: 99%

See 2 more Smart Citations

A computational investigation of patient factors contributing to contact stress abnormalities in the dysplastic hip joint

Thomas¹

View full text Add to dashboard Cite

Theses and DissertationsFall 2017 A computational investigation of patient factors contributing to A computational investigation of patient factors contributing to contact stress abnormalities in the dysplastic hip joint contact stress abnormalities in the dysplastic hip joint ABSTRACT Acetabular dysplasia, a deformity characterized by the presence of a shallow acetabulum inadequately covering the femoral head, alters force transfer through a joint, causing early-onset hip pain and degeneration. Dysplasia is often treated surgically with a periacetabular osteotomy (PAO), which permits multiplanar acetabular reorientation to stabilize the joint and alleviate pain. PAO alters joint mechanics, including contact stress, which can be assessed via computational methods.This work sought to enhance a discrete element analysis (DEA) model for assessment of the dysplastic hip. The primary focus was on understanding how the gait parameters used to load a DEA model affect the computed contact stress. Several additional studies focused on understanding specific anatomic and demographic factors contributing to the contact stress evaluation were also performed.Implementation of a dysplastic gait pattern to load the DEA models resulted in more cases with improved contact stress and clinical measures after PAO, which concurred with clinical findings. Patient demographics and acetabular and femoral geometry all affected the computed contact stress distributions, emphasizing the importance of proper cohort categorization prior to interpretation of DEA-calculated contact stress. These results indicate that accurate modeling of the particular deformity in this cohort likely requires evaluation of both functional and anatomic differences.These studies improve the ability to realistically model and characterize dysplastic hip contact mechanics. DEA is a valuable tool for assessing contact stress in dysplastic joints, which has the potential to improve patient outcomes by guiding clinicians in nonoperative treatment, pre-operative PAO planning, and evaluating intraoperative success. iv PUBLIC ABSTRACTHip dysplasia is a deformity of the pelvic bone that results in a mechanically unstable hip joint. This can be painful and lead to development of arthritis at a young age.Treatment may involve surgery to change how the hip socket is positioned and oriented in the pelvis to improve hip stability and decrease the damaging, painful stresses on the hip socket. Success of this realignment is largely determined by the ability of the surgeon to determine hip function in 3D from 2D X-ray images that can be obtained during surgery.Computational modeling offers the opportunity for analysis of joint mechanical function in 3D, which provides a much more realistic assessment of the mechanical changes after surgery.The purpose of this work was to develop the best method for using a specific type of computational modeling to evaluate changes in the joint mechanics of dysplastic hips before and after corrective surgery. This involved an investigation of mo...

show abstract

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

Gustafson

Elias

Debski

et al. 2019

Journal of Biomechanics

View full text Add to dashboard Cite

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%

show abstract

Large population evaluation of contact stress exposure in articular joints for prediction of osteoarthritis onset and progression

Abstract: viii cycle. Axial loading on the tibia is the subject body weight scaled according to the phase of gait. A spring is applied to the talus to represent the stabilization of the tibia.

Cited by 5 publications

References 94 publications

Validation and applications of discrete element analysis in the hip joint

Validation and applications of discrete element analysis in the hip joint

A computational investigation of patient factors contributing to contact stress abnormalities in the dysplastic hip joint

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

Contact Info

Product

Resources

About