METHODS: A group of European French-speaking experts participated in an email Delphi process. Definitions were identified during a systematic search of the PubMed database. Five definitions of arthritis, eight for osteomyelitis and five for bone or joint infections in general were included in a three-round process. We sought two sorts of definitions: definitions for \'definitive\' diagnoses for epidemiological studies and definitions for \'probable\' diagnoses for clinical or therapeutic studies, considering enlarged criteria.
RESULTS: Ten experts were involved in the Delphi process. A consensus was reached for a definitive diagnosis of arthritis, osteomyelitis and bone or joint infections in general. A consensus was also reached for a probable diagnosis of bone or joint infections in general.
CONCLUSIONS: This Delphi process made consensus definitions and criteria available for bone or joint infections that could improve the comparability of both epidemiological and clinical studies. This is a first step to standardise diagnostic criteria and distinguish definitive and probable bone or joint infections in children.