Beyond infection: recognizing and managing chronic non-bacterial osteitis – a review for orthopaedic practice

Abstract

Chronic non-bacterial osteitis (CNO) is a rare autoinflammatory bone disease encompassing a spectrum of conditions including, chronic recurrent multifocal osteomyelitis (CRMO), and SAPHO syndrome. The hallmark is sterile osteitis, driven by innate immune dysregulation rather than infection. Although first described in 1972, CNO remains significantly under-recognized with consequent diagnostic delays. The condition most frequently involves the anterior chest wall and clavicle, but any bone may be affected; multifocal and bilateral symmetric involvement is characteristic. Orthopaedic surgeons may encounter these patients during workup for suspected infection or malignancy. Delayed diagnosis can lead to prolonged antimicrobial treatment, repeated biopsies and missed therapeutic windows. This article summarises the current understanding of CNO pathophysiology, describes the clinical and radiological features across paediatric and adult populations, outlines a structured diagnostic approach, and presents a stepwise management algorithm. Specific orthopaedic considerations – including the indications for biopsy, the role of whole-body MRI, indication for surgical intervention, and management of complications such as vertebral collapse and growth disturbance – are addressed. Two illustrative cases are presented. Early recognition and prompt referral to a specialist multidisciplinary team underpins optimal outcomes.