Bone and joint sepsis occurs in 20% of newborns having perinatal sepsis. The feature of septic arthritis against the background of age-specific functional immunodeficiency gives us a reason to consider this decease as the manifestation of immunodeficiency. Septic arthritis in newborns is lethal in 10% of cases and gives orthopedic complications in 20% of cases. The starting moments of septic arthritis development are: mother's intrauterine infection and nosocomial infecting in maternity hospitals and intensive care departments, and purulent omphalitis.

We present the experience of diagnostics and treatment of 180 newborns aged 3 days and older having septic affection of the hip, knee, shoulder and other joints. The crucial role in diagnostics of septic arthritis is played by: cytology of smear, ultrasonic examination of a joint, X-ray examination of a joint, bacteriological, serological, PCR and PCT-Q. The bacteriological monitoring in 30% of newborns among the pathogens showed CoMRSA, often mixed with fungi and Pseudomonas aerogenes or Klebsiella pneumonia, and in 10% there was PCR of Toxoplasma gondi, Chlamidia trachomatis or cytomegalovirus. Immunological monitoring allowed one to determine the patients who needed substitute therapy by immunoglobulin and a number of immunomodulators. The degree of infection process severity and the adequacy of antibacterial therapy are determined by serologic investigations, PCR and PCT-Q. The treating complex included joint lavage, antibiotics, anticytokine, antifungal agents, probiotics, and magnetic-laser therapy.

The lethality was reduced to zero, transition into the chronic form was up to 2.5%, and orthopedic complications were presented in 10% of cases.

The after-history of treatment was researched and showed that when the diagnosis was made in less than 3 days, complications occurred in 3.3% of cases, and after 6–7 days the complications occurred in 22.4% of patients.