To study the diagnostic performance of infrared spectroscopy on fresh synovial fluids in early septic arthritis diagnosis in patients with acute joint effusion

Diagnosis of a joint effusion is frequently a medical emergency, especially when septic arthritis is suspected. Septic arthritis diagnosis relies on microscopic and bacteriological analysis of synovial fluid obtained by arthrocentesis. Direct microscopic examination can be made within 2 to 12 hours but it is negative in about 50 % of the cases. It is necessary to wait 72 hours to obtain the result of the culture and reasonably rule out the diagnosis of septic arthritis. A method of establishing an immediate etiological diagnosis could improve the care of patients with joint effusion that is a therapeutic emergency and justify a hospitalization and a parenteral antibiotic therapy.

Inclusion Criteria:

• patients over 18 year old
• patients with an acute arthritis defined by an evolution of less than 6 weeks
• patients benefiting from joint fluid puncture for diagnostic purposes in the rheumatology hospitals participating in the study
• patients who received information about the protocol and have not expressed opposition to participate

Exclusion Criteria:

• patients opposing the study
• protected major (safeguard justice, trusteeship and guardianship) and persons deprived of liberty

Patients benefiting from joint fluid puncture for diagnostic purposes in the rheumatology hospitals participating in the study