Acute osteomyelitis and septic arthritis are uncommon diseases in childhood that affect previously healthy children. A high index of suspicion, early diagnosis, initiation of appropriate antibiotic treatment and surgical intervention are essential for a good outcome.

The aim of our study was to evaluate our approach, clinical signs and the outcome of the diseases.

We retrospectively analyzed clinical, laboratory and microbiologic data in children hospitalized for acute haematogenous osteomyelitis or septic arthritis at the Department of Orthopaedic surgery in a 10-year period (from 2003 to 2013). Follow-up of outpatients was continued for at least 1 year or until the full recovery.

Acute haematogenous osteomyelitis or septic arthritis were confirmed in 22 patients, 14/22 (64%) had osteomyelitis and 8/22 (36%) arthritis, 16/22 (73%) were boys. The mean patient age was 9,3 years (SD:3,5), the median of the hospitalization was 32 days (IQR:13 – 60 days).

In children with osteomyelitis 10/14 (72%) had affected lower limb and in 4/14 (28%) the spine was affected. Six (80%) children had septic arthritis of the knee, hip joint was affected in one child and sacroiliac joint in one as well. We obtained blood cultures in 19/22 (86%) patients, bone biopsy was performed in 14/22 (64%). All infections were monomycrobial, Staphylococcus aureus was the most common pathogen, as expected.

In one patient the cause of the osteomyelitis was Panton-Valentine leucocidin (PVL) producing S. aureus. The characterics are presented in Table 1. All affected children recovered completely.

We observed 22 cases of pediatric bone and joint infections in a 10-year period. The most common pathogen was Staphylococcus aureus, as expected, althogh in more than half of cases no pathogens were found. One child suffered from osteomielitis caused by S. aureus strain producing PVL. We observed higher proportion of spine invovelment than previously reported in the literature.

To retrospectively analyze the etiology and microbiological results of synovial fluid culture, periprosthetic tissue culture and sonication fluid culture in 74 episodes of prosthetic joint infection (PJI) in 66 patients treated at the Department for Orthopaedic Surgery in 5 years period.

PJI was diagnosed according to the standard definition criteria (1). Conventional microbiological methods were used together with sonication of explanted prosthesis and sonication fluid culture.

The results are presented in Table 1. Acute PJI were more common in female patients (72%), whereas delayed PJI occurred in both sexes equally. Surprisingly, among acute PJI streptococcal (especially Streptococcus agalactiae) PJI were as common as Staphylococcus aureus PJI; we also observed high percentage of polymicrobial PJI (26 % among acute PJI and 30 % among delayed PJI), whereas 6/21 (28.6%) were detected by sonication fluid culture only. Preoperative synovial fluid culture identified the pathogen in 91.3% of acute PJI and in 63.2% of delayed PJI. Sonication fluid culture identified causative pathogens in 85% of acute PJI and in 95% of delayed PJI. In acute PJI 24/34 (70.6%) patient had concordant microbiological results between standard cultures and sonication fluid cultures, whereas in 4/34 (11.7%) microorganisms were detected by sonication fluid culture only and in 6/34 (17.6%)by tissue culture only. 23/40 (57.5%)patients with delayed PJI had concordant microbiological results; in 3/40 (7.5%) pathogens were detected by sonication fluid culture only.

We found sonication as very useful additional method in diagnostics of PJI, especially low grade PJI. At the same time we observed high percentage of positive and concordant mcrobiological results between all three microbiological methods in patients with acute PJI.