Accurate prosthesis classification is critical for total joint arthroplasty surveillance and assessment of comparative effectiveness. Historically, prosthesis classification was based solely on the names of the prosthesis manufacturers. As a result, prosthesis designs changed without corresponding name changes, and other prostheses’ names changed over time without substantial design modifications. As the number of prostheses used in total joint arthroplasty on the market increased, catalog and lot numbers associated with prosthesis descriptions were introduced by manufacturers. Currently, these catalog and lot numbers are not standardized, and there is no consensus on categorization of these numbers into brands or subbrands. Classification of the attributes of a prosthesis also varies, limiting comparisons of prostheses across studies and reports. The development of a universal prosthesis classification system would standardize prosthesis classification and enhance total joint arthroplasty research collaboration worldwide. This is a current area of focus for the International Consortium of Orthopaedic Registries (ICOR).