[Neonatal infections of the bones and joints]

Neonatal osteoarticular infections remain rare, with an estimated incidence of 1 to 3 cases per 1000 admissions to Neonatal Intensive Care Units. It usually results from bacteraemia and may thus be induced by IV catheters. More rarely it is due to direct inoculation secondary to cutaneous damage, or extension of soft tissue infection. The particularity of bone vascularization in the newborn explains the frequency of abscess formation in the periosteum or in soft tissues. The main pathogen involved is S. aureus (3/4 of cases), followed by group B streptococci and enterobacteriacae. Infection consists mainly of localised and slowly progressing abscesses. However, multifocal and severe infection is possible, in particular when caused by an IV catheter. Ultrasonography is the best initial investigation, possibly leading to surgical care. Medical treatment must include 2 synergistic antistaphyloccocal antibiotics, possibly associated with cefotaxime. The outcome is generally favorable, but orthopaedic consequences may emerge if the growth plate is involved. Rare specific causes, such as syphilis or tuberculosis, should also be evoked, but the clinical context is generally helpful for the diagnosis.