Objective. To document more fully the characteristics of chronic recurrent multifocal osteomyelitis (CRMO) in pediatric patients, to collect data on the outcomes and management of the disease, and to define prognostic factors.Methods. One hundred seventy-eight patients were included (123 female patients and 55 male patients), with a mean ؎ SD age at diagnosis of 10.9 ؎ 2.9 years. Inclusion criteria were a diagnosis of CRMO, evidence of at least one lesion of osteitis confirmed by imaging, and development of the syndrome before age 18 years.Results. Longitudinal clinical and imaging studies revealed that only 12 of 178 CRMO patients (7%) had unifocal lesions at the last medical visit. We were able to apply the clinical chronic nonbacterial osteomyelitis score to 110 of 178 patients (62%), which indicated that bone biopsy could have been avoided in 27 cases (25%). At the last medical visit, disease was in remission in only 73 of 171 patients (43%) (41% receiving therapy) after a mean ؎ SD of 47.9 ؎ 38.9 months; 44 of 171 patients (26%) experienced sequelae. Using cluster analysis, the CRMO cohort was separated into 3 homogeneous phenotypes (severe, mild, and intermediate). Patients with the severe phenotype had the worst prognosis. This group was entirely composed of male patients, most of whom had the multifocal form of CRMO and inflammatory syndrome. Patients with the mild phenotype had the best prognosis. This group was primarily composed of female patients with a unifocal form of CRMO and infrequent clavicle involvement and inflammatory syndrome. Patients with the intermediate phenotype had a good prognosis but greater reliance on treatment. This group primarily included female patients with multifocal lesions and inflammatory syndrome.Conclusion. This is the largest CRMO cohort described in the literature to date. Clinical evolution and imaging investigations confirmed the multifocal pattern of the disease. Three distinct subgroups of CRMO patients were distinguished, with very different prognoses.

Background Various observations have suggested that the course of COVID-19 might be less favourable in patients with inflammatory rheumatic and musculoskeletal diseases receiving rituximab compared with those not receiving rituximab. We aimed to investigate whether treatment with rituximab is associated with severe COVID-19 outcomes in patients with inflammatory rheumatic and musculoskeletal diseases.Methods In this cohort study, we analysed data from the French RMD COVID-19 cohort, which included patients aged 18 years or older with inflammatory rheumatic and musculoskeletal diseases and highly suspected or confirmed COVID-19. The primary endpoint was the severity of COVID-19 in patients treated with rituximab (rituximab group) compared with patients who did not receive rituximab (no rituximab group). Severe disease was defined as that requiring admission to an intensive care unit or leading to death. Secondary objectives were to analyse deaths and duration of hospital stay. The inverse probability of treatment weighting propensity score method was used to adjust for potential confounding factors (age, sex, arterial hypertension, diabetes, smoking status, body-mass index, interstitial lung disease, cardiovascular diseases, cancer, corticosteroid use, chronic renal failure, and the underlying disease [rheumatoid arthritis vs others]). Odds ratios and hazard ratios and their 95% CIs were calculated as effect size, by dividing the two population mean differences by their SD. This study is registered with ClinicalTrials.gov, NCT04353609.

The aim of this study was to evaluate the diagnostic value of technetium-99m hexamethylpropylene amine oxime leucocyte scintigraphy (HMPAO-LS) by means of a retrospective review of 116 patients divided into three groups of bone and joint infection. One hundred and thirty-one LS examinations were performed, and 143 sites analysed. The final diagnosis of infection was based on surgical, histological and bacteriological data and follow-up. Ninety-four suspected localizations were examined in group 1, which included 74 patients with an infection suspected to involve orthopaedic implants. In this group, there were 38 true-positives, 1 false-negative, 49 true-negatives and 6 false-positives. Surgical confirmation was obtained in 34 cases. In group 2 (24 patients with suspected osteomyelitis), there were 27 localizations of which 14 were true-positives and 13 were true-negatives (including seven surgical confirmations). In group 3 (18 patients suspected of septic arthritis) there were eight true-positives, two false-negatives, ten true-negatives and two false-positives. Overall sensitivity of 99mTc-HMPAO-LS for the detection of bone and joint infection was 95%, with a specificity of 90% (group 1: sensitivity 97%, specificity 89%; group 2: 100% and 100%; group 3: 80% and 83%). It may be concluded that HMPAO-LS is an effective tool for the diagnosis of both bone infection involving implants and chronic osteomyelitis.

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