In vitro wear testing of a contemporary design of reverse shoulder prosthesis.
Reverse shoulder arthroplasty is an increasingly common surgical intervention. However there are concerns and known limitations in relation to such joint replacement, while novel designs of reverse shoulder prostheses continue to appear on the market. Many claim to offer improvements over older designs but such assertions are difficult to validate when there is no consensus as to how such implants should be tested in vitro or even if such testing is necessary. In order to permit appropriate in vitro testing of reverse shoulder prostheses a unique, multi-station test rig was designed which was capable of applying motion in three axes to test prostheses. The shoulder simulator can apply up to 110° of motion in the flexion-extension and abduction-adduction axes and up to 90° in the internal-external rotation axis. Dynamic loading of up to 1500 N can be provided. The simulator is computer controlled so that the motions and loading associated with particular activities of daily living can be applied. A 4.5 million cycle wear test of commercially available reverse shoulder prostheses was undertaken using a 'mug to mouth' activity of daily living. Gravimetric analysis was used to characterise wear. After 4.5 million cycles of 'mug to mouth', the average wear rate of the test components was 14.3mm(3)/million cycles. Polyethylene test components showed a reduction in roughness and the median wear particle diameter was 167 nm. A three axis shoulder simulator has been designed and used to successfully test multiple samples of a commercially available reverse shoulder prosthesis.
School of Mechanical and Systems Engineering, Newcastle University, Claremont Road, Newcastle upon Tyne, NE1 7RU England, UK.
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Smith
School of Engineering, Technology and Maritime Operations, Liverpool John Moores University, James Parsons Building, Byrom Street, England, UK.
B L
BL
Li
Biomedical Engineering Department, Al-khwarizmi Engineering College, Baghdad University, Iraq.
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A
Buniya
School of Mechanical and Systems Engineering, Newcastle University, Claremont Road, Newcastle upon Tyne, NE1 7RU England, UK.
S Ho
SH
Lin
School of Mechanical and Systems Engineering, Newcastle University, Claremont Road, Newcastle upon Tyne, NE1 7RU England, UK.
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SC
Scholes
School of Mechanical and Systems Engineering, Newcastle University, Claremont Road, Newcastle upon Tyne, NE1 7RU England, UK.
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G
Johnson
School of Mechanical and Systems Engineering, Newcastle University, Claremont Road, Newcastle upon Tyne, NE1 7RU England, UK. Electronic address: Thomas.joyce@ncl.ac.uk.
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TJ
Joyce
D000203:Activities of Daily Living; D019643:Arthroplasty, Replacement; D008422:Materials Testing; D055595:Mechanical Phenomena; D020959:Polyethylene; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D012785:Shoulder Joint / Q000502:physiology / Q000601:surgery*
D020959:Polyethylene
Polyethylene; Reverse shoulder prosthesis; Shoulder simulator; Wear particles; Wear test