Effect of Interface Conditions between Ultrahigh Molecular Weight Polyethylene and Polymethyl Methacrylate Bone Cement on the Mechanical Behaviour of Total Shoulder Arthroplasty

The aim of this study was to investigate the effect of the interface condition between polymethyl methacrylate (PMMA) bone cement and the ultrahigh molecular weight (UHMWPE) glenoid component on cement stresses and glenoid component tilting in a finite element (FE) model. The background of this research is that most FE models assume bonding between the PMMA bone cement and the UHMWPE component, although it is very doubtful that this bonding is present. An FE model of a cemented glenoid component was developed and a joint compression force and subluxation force of 725 and 350 N respectively were applied. The maximal principal stresses in the cement layer ranged between 21.30 and 32.18 MPa. Glenoid component tilting ranged between 0.943° and 0.513°. It was found that the interface condition has a large effect on the maximal principal stresses and glenoid component tilting. Whether adhesion between the UHMWPE component and PMMA bone cement occurs is unknown beforehand and, as a result, design validation using the FE technique should be carried out both by using contact elements in combination with a coefficient of friction as well as by a full bonding at this interface.

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Designer Cranioplasty at Budget Prices: A Novel Use of 3D Printing Technology

Indian Journal of Neurosurgery ◽

10.1055/s-0040-1716995 ◽

2021 ◽

Author(s):

Thirumal Yerragunta ◽

Reddy Ramanadha Kanala ◽

Vamsi Krishna Yerramneni ◽

Swapnil Kolpakawar ◽

Vasundhara Rangan

Keyword(s):

Patient Satisfaction ◽

3D Printing ◽

Bone Cement ◽

Polymethyl Methacrylate ◽

Printing Technology ◽

3D Printing Technology ◽

Pmma Bone Cement ◽

Custom Made ◽

3D Printed ◽

Exact Shape

Abstract Background Cranioplasty using synthetic materials for restoration of the exact shape of the skull has always remained a challenge until the development of 3D printing technology. However, the high-cost of available 3D printed implants limits their extensive use. Objectives To study the effectiveness of a low-cost, 3D-printed template for molding the polymethyl methacrylate (PMMA) (bone cement) in order to achieve exact contours of the skull specific to each patient. Materials and Methods 10 cranioplasties have been performed between July 2018 to December 2019 in a variety of craniotomy defects using bone cement flaps shaped using custom-made molds. The mold was 3D-printed and based on each patient’s CT images in digital imaging and communications in medicine (DICOM). Miniplates and screws were used to fix the flap. Postoperatively, clinical and radiological evaluation were done to assess patient satisfaction and accuracy of contour achieved. Results Patient satisfaction as well as accuracy of contouring, as seen on postoperative CT scans, were excellent. There were no notable complications on follow-up. Conclusion PMMA cranioplasty flap, contoured using a 3D-printed mold, is a very cost-effective alternative for restoration of skull contour for various craniotomy defects.Polymethyl methacrylate (PMMA) molded to form the exact shape of lost calvarium using 3D printed plastic templates is a smart and economical solution

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