Hani Haider, Joel N Weisenburger, Kevin L Garvin. Simultaneous measurement of friction and wear in hip simulators. Proc IMechE, Part H: Journal of Engineering in Medicine; 230(5): 373-388. DOI: 10.1177/0954411916644476 On page 379 of this article, there is an error in the equation "[Formula: see text]". The corrected equation is as follows: [Formula: see text] The online version of the article has been updated.