Total Shoulder Arthroplasty Biomechanics: A Study of the Forces and Strains at the Glenoid Component

1998 ◽  
Vol 120 (1) ◽  
pp. 92-99 ◽  
Author(s):  
A. R. Karduna ◽  
G. R. Williams ◽  
J. P. Iannotti ◽  
J. L. Williams
Keyword(s):  
Rigid Body ◽  
Glenohumeral Joint ◽  
Articular Surface ◽  
Total Shoulder Arthroplasty ◽  
Contact Forces ◽  
Glenoid Component ◽  
Rigid Body Model ◽  
Joint Contact ◽  
Component Loading ◽  
Force Displacement

The objective of this study was to examine how changes in glenohumeral joint conformity and loading patterns affected the forces and strains developed at the glenoid. After removal of soft tissue (muscles, ligaments, and labrum), force-displacement data were collected for both natural and prosthetically reconstructed joints. Joints were shown to develop higher forces for a given translation as joint conformity increased. A rigid body model of joint contact forces was used to determined the so-called effective radial mismatch of each joint. For the purposes of this study, the effective radial mismatch is defined as the mismatch required for a rigid body joint to have the same force-displacement relationship as the joint in question. This parameter is an indication of the deformation at the articular surface. The effective radial mismatch dramatically increased with increasing medial loads, indicating that under physiological loads, the effective radial mismatch of a joint is much greater than its measured mismatch at no load. This increase in effective mismatch as medial loads were increased was found to be threefold greater in cartilaginous joints than in reconstructed joints. Rosette strain gages positioned at the midlevel of the glenoid keel in the reconstructed joints revealed that anterior/posterior component loading leads to fully reversible cyclic keel strains. The highest compressive strains occurred with the head centered in the glenoid, and were larger for nonconforming joints (ε = 0.23 percent). These strains became tensile just before rim loading and were greater for conforming joints (ε = 0.15 percent). Although recorded peak strains are below the yield point for polyethylene, the fully reversed cyclic loading of the component in this fashion may ultimately lead to component toggling and implant failure.

scholarly journals Micromachined Tactile Sensor Array for RTSA

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1430
Author(s):  
Elliott C. Leinauer ◽  
Hyunmin M. Kim ◽  
Jae W. Kwon
Keyword(s):  
Soft Lithography ◽  
Glenohumeral Joint ◽  
Total Shoulder Arthroplasty ◽  
Tactile Sensor ◽  
Capacitive Sensor ◽  
Contact Forces ◽  
Joint Reaction Forces ◽  
Implant Size ◽  
Joint Contact ◽  
Reaction Forces

This work presents a polymer-based tactile capacitive sensor capable of measuring joint reaction forces of reverse total shoulder arthroplasty (RTSA). The capacitive sensor contains a polydimethylsiloxane (PDMS) dielectric layer with an array of electrodes. The sensor was designed in such a way that four components of glenohumeral contact forces can be quantified to help ensure proper soft tissue tensioning during the procedure. Fabricated using soft lithography, the sensor has a loading time of approximately 400 ms when a 14.13 kPa load is applied and has a sensitivity of 1.24 × 10−3 pF/kPa at a load of 1649 kPa. A replica RTSA prothesis was 3D printed, and the sensor was mounted inside the humeral cap. Four static right shoulder positions were tested, and the results provided an intuitive graphical description of the pressure distribution across four quadrants of the glenohumeral joint contact surface. It may help clinicians choose a right implant size and offset that best fit a patient’s anatomy and reduce postoperative biomechanical complications such as dislocation and stress fracture of the scapula.

Quantitative Assessment of Glenohumeral Joint Forces in Positions of Overhead Activities: Effects of Shoulder Arthroplasty

2002 ◽  
Author(s):  
Thay Q. Lee ◽  
Mark Schamblin ◽  
Bruce Y. Yang ◽  
Michelle H. McGarry ◽  
Ranjan Gupta
Keyword(s):  
Shoulder Arthroplasty ◽  
Glenohumeral Joint ◽  
Total Shoulder Arthroplasty ◽  
Glenoid Component ◽  
Shoulder Hemiarthroplasty ◽  
Adequate Pain Relief ◽  
Joint Forces ◽  
Before And After ◽  
Total Knee ◽  
Component Loosening

Glenohumeral arthroplasty as well as hemiarthroplasty, although providing adequate pain relief, has not shared in the success of similar joint replacement procedures such as total knee arthroplasty or total hip arthroplasty. Short comings of this procedure include a decreased range of motion postoperatively as well as increased incidents of glenoid component loosening in total shoulder procedures. This is especially a problem in the end ranges of motion where eccentric loading of the glenoid component are thought to occur. The purpose of this study was to quantify the glenohumeral joint forces before and after bipolar shoulder hemiarthroplasty and total shoulder arthroplasty for positions simulating overhead activities and commonly relied upon by the wheelchair dependent individual.

Effect of Implant Shape and Material Properties on Stresses in the Glenoid Components of Total Shoulder Arthroplasties: A Finite Element Analysis

2010 ◽  
Author(s):  
Jingzhou Zhang ◽  
Charlie Yongpravat ◽  
Marc D. Dyrszka ◽  
William N. Levine ◽  
Thomas R. Gardner ◽  
...  
Keyword(s):  
Humeral Head ◽  
Glenohumeral Joint ◽  
Total Shoulder Arthroplasty ◽  
Peak Stress ◽  
Glenoid Component ◽  
Joint Stability ◽  
Element Analysis ◽  
Total Shoulder Arthroplasties ◽  
Shoulder Arthroplasties ◽  
Glenoid Loosening

The geometry of the glenohumeral joint is osseous, naturally nonconforming and minimally constrained, thus the essential requirement of a glenohumeral prosthesis in total shoulder arthroplasty (TSA) is prevention of joint degeneration and glenoid loosening. A variety of glenoid prostheses have been developed. Nonconforming glenohumeral implants are common for TSA. However, the nonconforming shape increases the instability when the humeral head is in the central region, where motion frequently occurs. Conforming implants can increase joint stability, but the “rocking-horse” effect [1] caused by the conforming shape is thought to lead to high stresses and moments at the glenoid rim when the humeral head approaches the periphery during its range of motion. The hybrid design, with a conforming center and a nonconforming periphery, combines the advantages of both nonconforming and conforming implant geometries. It has been shown [2] that the peak stress generated in glenoid components during activities of daily living can be as high as 25 MPa, which exceeds the polyethylene yield strength of the glenoid component and can lead to wear and cold flow of the component. Polyethylene has also been shown to be viscoelastic [3]. Therefore, both elastic-plastic and viscoelastic-plastic models of the glenoid implant were used to determine how viscoelasticity affected stress in the implant. The effects of implant shape on the stresses in the center, transition, and superior zones for the three different glenoid implant shapes, as well as on the stress in the underlying cement and bone, were determined in this study.

A Pseudo-Rigid-Body Model for Rolling-Contact Compliant Beams

2007 ◽  
Author(s):  
Allen B. Mackay ◽  
Spencer P. Magleby ◽  
Larry L. Howell
Keyword(s):  
Rigid Body ◽  
Rolling Contact ◽  
Model Parameters ◽  
Displacement Curve ◽  
Cantilever Beams ◽  
Body Model ◽  
Rigid Body Model ◽  
Contact Surfaces ◽  
Definition Of ◽  
Force Displacement

This paper presents a pseudo-rigid-body model (PRBM) for rolling-contact compliant beams (RCCBs). The loading conditions and boundary conditions for the RCCB can be simplified to an equivalent cantilever beam that has the same force-deflection characteristics as the RCCB. Building on the PRBM for cantilever beams, this paper defines a model for the force-deflection relationship for RCCBs. The definition of the RCCB PRBM includes the pseudo-rigid-body model parameters that determine the shape of the beam, the length of the corresponding pseudo-rigid-body links and the stiffness of the equivalent torsional spring. The behavior of the RCCB is parameterized in terms of a single parameter defined as clearance, or the distance between the contact surfaces. RCCBs exhibit a unique force-displacement curve where the force is inversely proportional to the clearance squared.

Force-Displacement Model of the FlexSuRe™ Spinal Implant

2010 ◽  
Author(s):  
Eric Stratton ◽  
Larry Howell ◽  
Anton Bowden
Keyword(s):  
Rigid Body ◽  
Virtual Work ◽  
Implant Design ◽  
Element Analysis ◽  
Spinal Implant ◽  
Body Model ◽  
Flexion Extension ◽  
Rigid Body Model ◽  
Displacement Model ◽  
Force Displacement

This paper presents modeling of a novel compliant spinal implant designed to reduce back pain and restore function to degenerate spinal disc tissues as well as provide a mechanical environment conducive to healing of the tissues. Modeling was done through the use of the pseudo-rigid-body model. The pseudo-rigid-body model is a 3 DOF mechanism for flexion-extension (forward-backward bending) and a 5 DOF mechanism for lateral bending (side-to-side). These models were analyzed using the principle of virtual work to obtain the force-deflection response of the device. The model showed good correlation to finite element analysis and experimental results. The implant may be particularly useful in the early phases of implant design and when designing for particular biological parameters.

Design of a New Fully Compliant Translational Joint via Straight-Line Motion Mechanism Based Method

2019 ◽  
Author(s):  
Sonia C. García ◽  
Juan A. Gallego-Sanchez
Keyword(s):  
Rigid Body ◽  
Symmetry Axis ◽  
Initial Position ◽  
Element Analysis ◽  
Motion Mechanism ◽  
Body Model ◽  
Straight Line ◽  
Rigid Body Model ◽  
Translational Joint ◽  
Force Displacement

Abstract A Compliant Translational Joint (CTJ) is designed via Straight-Line Motion Mechanism Method. The designed CTJ is based on the Pseudo-Rigid-Body-Model (PRBM) of a modified Scott-Russell Mechanism. The precision of the straight-line motion of the rigid-body mechanism adjusts to a straight-line to a 99.6% while the compliant version adjusts to a 99.9%. The novelty of the design is given by the way the CTJ is designed, the performance of the CTJ is achieved by mirroring the mechanism about an axis tangent to the path of the mechanism and that passes through the initial position of the coupler point at the symmetry axis of the path. The CTJ motion is predicted by the PRBM. The force-displacement relations and the frequency modes of the CTJ are analyzed using finite element analysis (FEA).

Meniscal Implant Biomechanical Performance: A Novel Quantitative Approach

2009 ◽  
Author(s):  
Jonathan J. Elsner ◽  
Eran Linder-Ganz ◽  
Amir Danino ◽  
Farshid Guilak ◽  
Avi Shterling
Keyword(s):  
Peak Pressure ◽  
Articular Surface ◽  
Contact Forces ◽  
Joint Degeneration ◽  
Partial Loss ◽  
Short Term ◽  
Degenerative Arthritis ◽  
Articular Surfaces ◽  
Joint Contact

One of the functions of the meniscus is to distribute contact forces over the articular surfaces by increasing joint contact areas [1]. It is widely accepted that total/partial loss of the meniscus increases the risk of joint degeneration. A short-term method for evaluating whether degenerative arthritis can be prevented would be to determine if peak pressure and contact area coverage of the tibialis plateau (TP) articular surface in the knee are restored at the time of implantation. Although several published studies already utilized TP contact pressure measurements as an indicator for biomechanical performance of allograft menisci [2,3], there is a paucity of a quantitative method for evaluation of these parameters in situ with a single effective parameter. In the present study, we developed such a method and employed it on sheep and human cadaveric knees.

Stable Workpiece Fixturing

1994 ◽  
Author(s):  
Joseph P. Donoghue ◽  
W. Stamps Howard ◽  
Vijay Kumar
Keyword(s):  
Rigid Body ◽  
Relative Motion ◽  
Material Removal ◽  
Three Dimensional ◽  
Quality Measure ◽  
Contact Forces ◽  
Force Displacement

Abstract In this paper, we present the spatial and planar force-displacement relationships which characterize individual contacts on a fixtured workpiece. The compliance at each contact is modeled and expressions for the changes in contact forces as a function of the rigid body relative motion between the fixture elements and the workpiece are developed for three-dimensional fixtures. Using these relationships, the stable fixturing of planar workpieces is demonstrated for material-removal operations. By example, we first describe how to choose the clamp geometry so the overall movement of the workpiece is minimized and then determine the “best” two-contact clamping arrangement using a quality measure based on the deviation from the nominal part dimensions.

scholarly journals A rigid body model for the assessment of glenohumeral joint mechanics: Influence of osseous defects on range of motion and dislocation

2016 ◽  
Vol 49 (4) ◽  
pp. 514-519 ◽  
Author(s):  
Mark F. Welsh ◽  
Ryan T. Willing ◽  
Joshua W. Giles ◽  
George S. Athwal ◽  
James A. Johnson
Keyword(s):  
Rigid Body ◽  
Range Of Motion ◽  
Glenohumeral Joint ◽  
Joint Mechanics ◽  
Body Model ◽  
Rigid Body Model ◽  
Osseous Defects
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