Various definitions and biomarkers have been developed in an unsuccessful attempt to obtain a "gold standard" for periprosthetic joint infection (PJI) diagnosis. The development of the 2011 Musculoskeletal Infection Society criteria facilitated further research and advances by allowing the use of a consistent PJI definition across studies. The newly proposed 2018 criteria do not rely at all on expert opinions/consensus. In this review, we describe the most relevant definitions developed throughout recent time, their rationale, characteristics, and supportive evidence for their clinical implementation. In the opinion of the authors, the orthopedic community should consider a probability and likelihood paradigm to create a PJI diagnostic definition. Probably not a single definition might be suited for all situations; the inclusion of serological findings could be the next step moving forward.