The goal of this study was to develop a prognostic scoring system for the development of prosthetic joint infection (PJI) that could risk-stratify patients undergoing total hip (THA) or total knee (TKA) arthroplasties.

Previously reported case-control study.

Tertiary referral care setting from 2001 through 2006.

A derivation data set of 339 cases and 339 controls was used to develop 2 scores. A baseline score and a 1-month-postsurgery risk score were computed as a function of the relative contributions of risk factors for each model. Points were assigned for the presence of each factor and then summed to get a subject's risk score.

The following risk factors were detected from multivariable modeling and incorporated into the baseline Mayo PJI risk score: body mass index, prior other operation on the index joint, prior arthroplasty, immunosuppression, ASA score, and procedure duration (c index, 0.722). The 1-month-postsurgery risk score contained the same variables in addition to postoperative wound drainage (c index, 0.716).

The baseline score might help with risk stratification in relation to public reporting and reimbursement as well as targeted prevention strategies in patients undergoing THA or TKA. The application of the 1-month-postsurgery PJI risk score to patients undergoing THA or TKA might benefit those undergoing workup for PJI.