Affiliations: Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4 | Committee on Evolutionary Biology, University of Chicago, Chicago, IL 60637
Note: [] Corresponding Author: K. H. S. Chan, Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4, Tel:+1-604-822-3373; Fax:+1-604-822-2416; Email: keithhsc@interchange.ubc.ca
Abstract: Ultra-high-molecular-weight polyethylene is an important constituent of hip implants. Surgical revisions are required because of implant loosening and osteolysis (destruction or resorption of bone tissue). We develop a mathematical and a computational model to determine implant life (defined as the time when 20% of the implants operating at a given wear rate is revised) based on wear rates and apply them to the data of Sochart (Clin Orthop Relat Res, 363:135–50, 1999). No significant difference was found between mathematical and computational model predictions (14.8 and 14.7 years, respectively) from the actual value of 15.0 ± 3.9 years (\bar{X} ± 2SE; P > 0.05). We find that an increase in cross-linking does not decrease implant life greatly. However, a large decrease in implant life occurs with an increase in surface roughness, cycles per year and body weight or a decrease in contact stress and femoral head radius.
Keywords: UHMWPE hip replacement, implant life, wear model
