Sonographic features and acquisition protocols for Charcot neuro-osteoarthropathy in diabetes: a scoping review protocol

<ns3:p> Background Charcot neuro-osteoarthropathy (CNO; Charcot foot) is an uncommon but serious complication of diabetes and is frequently misdiagnosed or recognised late. Delayed recognition is associated with severe consequences, including progressive deformity, ulceration, amputation and substantial morbidity. Imaging is central to recognition and monitoring. While magnetic resonance imaging is commonly used for early disease where radiographs are non-diagnostic, musculoskeletal ultrasound offers a portable, non-ionising modality that may depict cortical surface irregularity, effusion, synovitis, tenosynovitis and periarticular hypervascularity. However, reported sonographic findings and acquisition protocols are heterogeneous, and to date no scoping review has systematically mapped this evidence in CNO. Methods This protocol has been developed in accordance with JBI guidance for scoping reviews and is reported in accordance with PRISMA-P. The completed scoping review will be reported in accordance with PRISMA-ScR. A populated PRISMA-P checklist is provided (Extended data 2). Using the Population–Concept–Context framework, we will include studies of adults with diabetes and confirmed or clinically suspected CNO of the foot/ankle that report musculoskeletal ultrasound findings and/or acquisition protocol details. Studies focused solely on vascular/perfusion ultrasound without musculoskeletal assessment will be excluded. MEDLINE, Embase, CINAHL and Scopus will be searched from inception, with grey literature and citation tracking, and no language restrictions. Two reviewers will independently screen titles/abstracts and full texts. Data will be charted by one reviewer using a prespecified form and independently verified by a second reviewer. Findings will be synthesised using narrative summary and tables, mapping reported sonographic features and protocol parameters. No formal risk-of-bias assessment is planned. Discussion This scoping review will provide an evidence map of reported sonographic features and ultrasound acquisition protocols in CNO, identify gaps and inconsistencies in reporting, and inform future research including protocol standardisation and reproducibility-focused evaluation. <ns3:bold>Systematic review registration</ns3:bold> Open Science Framework: 10.17605/OSF.IO/ZRXWD </ns3:p>