Every patient that undergoes a HPRO procedure is included in the denominator - the replacement and revision are two separate procedures and should be counted as such. Either the patient has an infection at the time of surgery or he/she does not. The concept of "chronic infection" does not figure into the equation. The wound class is not assigned prior to the procedure, but at the conclusion of the procedure. If there does not appear to be an infection when the surgeon opens the patient, then it would be classified accordingly - if the patient then develops an infection it would be counted in the numerator.