Chronic recurrent multifocal osteomyelitis: the prevalence of lower-limb and foot involvement

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory condition. The lesions are reported to present most frequently in the long bones. This study aimed to review the presenting features of CRMO in a cohort of children diagnosed as having CRMO and to compare the level of agreement between the clinical and published diagnostic criteria.

A case notes review was undertaken of patients with a clinical diagnosis of CRMO. Patients were younger than 16 years at the time of diagnosis. Features were identified in each patient that agreed or disagreed with the published diagnostic criteria. The location of bone lesions in the lower limb at onset and disease progression was recorded.

A total of 37 patients were included. There was a high prevalence in white individuals. Agreement with the diagnostic criteria of Jansson et al and El-Shanti and Ferguson was poor, with levels of agreement of 40.5% and 43%, respectively, and low kappa scores (κ = 0.07 and 0.09, respectively). The lower limb was affected in 49% of patients at onset and in 72% overall.

This study presents one of the largest published cohorts of pediatric patients with CRMO and also presents racial/ethnic group data that have not previously been reported in other studies. Despite being a condition considered to affect the metaphysis of long bones, the ankle area and foot bones were also frequently affected. The agreement between the clinical diagnosis and the published diagnostic criteria was weak.