title: Numerical and experimental investigations for the evaluation of the wear coefficient of reverse total shoulder prostheses.
abstract: In the present study, numerical and experimental wear investigations on reverse total shoulder arthroplasties (RTSAs) were combined in order to estimate specific wear coefficients, currently not available in the literature. A wear model previously developed by the authors for metal-on-plastic hip implants was adapted to RTSAs and applied in a double direction: firstly, to evaluate specific wear coefficients for RTSAs from experimental results and secondly, to predict wear distribution. In both cases, the Archard wear law (AR) and the wear law of UHMWPE (PE) were considered, assuming four different k functions. The results indicated that both the wear laws predict higher wear coefficients for RTSA with respect to hip implants, particularly the AR law, with k values higher than twofold the hip ones. Such differences can significantly affect predictive wear model results for RTSA, when non-specific wear coefficients are used. Moreover, the wear maps simulated with the two laws are markedly different, although providing the same wear volume. A higher wear depth (+51%) is obtained with the AR law, located at the dome of the cup, while with the PE law the most worn region is close to the edge. Taking advantage of the linear trend of experimental volume losses, the wear coefficients obtained with the AR law should be valid despite having neglected the geometry update in the model.
authors.affiliation: Department of Civil and Industrial Engineering, Largo Lucio Lazzarino 2, Pisa 56126, Italy. Electronic address: l.mattei@ing.unipi.it.
authors.forename: Lorenza
authors.initials: L
authors.lastname: Mattei
authors.affiliation: Department of Civil and Industrial Engineering, Largo Lucio Lazzarino 2, Pisa 56126, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Di Puccio
authors.affiliation: School of Mechanical and Systems Engineering, Stephenson Building, Claremont Road, Newcastle upon Tyne, NE 1 7RU UK.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Joyce
authors.affiliation: Department of Civil and Industrial Engineering, Largo Lucio Lazzarino 2, Pisa 56126, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Ciulli
mesh_terms: D001178:Arthroplasty; D001672:Biocompatible Materials / Q000737:chemistry; D001696:Biomechanical Phenomena; D008422:Materials Testing; D055595:Mechanical Phenomena; D008962:Models, Theoretical; D008970:Molecular Weight; D019736:Prostheses and Implants; D012782:Shoulder / Q000601:surgery*
chemical_list: D001672:Biocompatible Materials
keywords: Cross-shear; In vitro wear tests; Reverse total shoulder arthroplasty; Wear coefficient; Wear law; Wear modeling