Retrospective Review of 80 Patients with Chronic Recurrent Multifocal Osteomyelitis Evaluated by Pediatric Orthopaedic Surgeons.

Chronic Recurrent Multifocal Osteomyelitis (CRMO) is a rare aseptic autoinflammatory disease with a wide and vague clinical presentation that often mimics infection, malignancy, or benign conditions, leading to a delayed diagnosis. We aimed to evaluate the clinical characteristics, differential diagnoses from evaluating pediatric orthopaedic surgeons, and compared the number of patients that could have avoided a biopsy in 80 patients with CRMO. Children diagnosed with CRMO at a single tertiary pediatric hospital in the United States between 2012 and 2022 who were evaluated by a pediatric orthopaedic surgeon were retrospectively reviewed. The differential diagnoses from the surgeons were recorded from their initial presentation. The Jansson criteria and Bristol Criteria were retrospectively applied to evaluate patients who could have been spared a biopsy. 80 children (65% female) with CRMO were identified. The mean age at diagnosis was 10.28 ± 3.52 years, follow-up of 37.13 ± 27.67 months, and delay in diagnosis of 6.21 ± 9.75 months. Common presenting symptoms were antalgic gait (45%), local inflammation (30%), and fever/fatigue (26.25%). 58% presented clinically with unifocal symptoms, but 81% had multifocal disease on imaging. Radiographs were unremarkable in 35%, had periosteal reaction/sclerosis (23%), or a lytic lesion (22%). On MRI, 72% of patients had marrow edema, periosteal reaction (23%), and/or osteitis (19%). 69% of patients received a whole-body MRI, and 75% received a bone biopsy. The femur, tibia, pelvis, and spine were involved in >30% of patients. The most common initial differential diagnoses were related to infection (34%) and neoplasm (21%). The Jansson criteria was found to be more sensitive than the Bristol criteria for diagnosing CRMO (OR 3.94, P < 0.001) and identified 80% that could have been spared biopsy. This cohort of 80 patients with CRMO in the U.S. displayed an ambiguous presentation. Whole-body MRI was useful for identifying multifocal lesions. In conjunction with clinical reasoning, the Jansson criteria may be useful in the diagnosis of CRMO and perhaps avoid an unnecessary bone biopsy. Level IV •Chronic Recurrent Multifocal Osteomyelitis is a rare condition in children with a delay in definitive diagnosis of approximately 6 months after initial presentation.•Chronic Recurrent Multifocal Osteomyelitis often has unremarkable radiographs and MRI findings similar to a neoplasm or infectious osteomyelitis.•The most common lesions were found in the femur, tibia, pelvis, and spine.•Pediatric orthopaedic surgeons evaluating these patients placed neoplasm/malignancy and infection on their differential most frequently.•The Jansson criteria may be used in some patients to possibly prevent unnecessary bone biopsies.