EC Orthopaedics

Bony islands, or enostoses, are benign medullary foci of compact bone most commonly encountered incidentally on radiographs. Their presence in the distal femur and proximal tibia is not uncommon, yet they are often misinterpreted as sinister sclerotic lesions, particularly in oncologic or trauma settings. Although enostoses are usually asymptomatic and stable over time, their dense radiographic appearance frequently prompts unnecessary tests or even invasive treatments because of worries about chronic osteomyelitis or metastatic illness. The imaging characteristics, diagnostic difficulties, and clinical decision-making processes pertaining to the bony islands surrounding the knee joint are all thoroughly explained in this position article. By drawing from both orthopaedic and radiological perspectives, the article underscores the importance of recognising these lesions early and correctly. It provides a pragmatic framework to differentiate enostoses from more aggressive pathologies using radiological signs such as lesion borders, periosteal reaction, and MRI signal characteristics. Furthermore, the discussion highlights the psychological, clinical, and economic consequences of overdiagnosis and proposes collaborative diagnostic strategies. The article emphasises the role of interdisciplinary understanding in minimising diagnostic errors and protecting patients from unnecessary interventions. It ultimately calls upon orthopaedic surgeons to be champions of imaging literacy, urging that these “sclerotic shadows” be viewed not with suspicion, but with informed clarity.

 Keywords: Enostosis; Knee Joint; Musculoskeletal Imaging; Bone Neoplasms; Diagnostic Errors

1. Greenspan A. “Bone island (enostosis): current concept-a review”. Skeletal Radiology 2 (1995): 111-115.
2. Murphey MD., et al. “From the archives of the AFIP: Imaging of benign musculoskeletal lesions”. Radiographics6 (2000): 1371-1395.
3. Kransdorf MJ and Murphey MD. “Imaging of soft tissue tumors”. 3^rd Philadelphia: Saunders (2006).
4. White LM and Kandel R. “MRI of musculoskeletal tumours: pearls, pitfalls and mimics”. American Journal of Roentgenology 3 (2002): 559-567.
5. O’Donnell P and Saifuddin A. “The prevalence and distribution of bone islands”. Skeletal Radiology 6 (2004): 331-336.
6. Douis H., et al. “Bone islands and their mimics: a pictorial review”. British Journal of Radiology 1058 (2016): 20150762.
7. Shah LM and Hanrahan CJ. “Musculoskeletal imaging pearls and pitfalls”. Radiologic Clinics of North America 6 (2014): 1087-106.
8. Frampas E., et al. “Imaging findings of enostoses and osteopoikilosis”. Diagnostic and Interventional Imaging 3 (2013): 301-310.
9. Resnick D. “Diagnosis of bone and joint disorders”. 4^th Philadelphia: Saunders (2002).
10. Nguyen JC., et al. “Radiologic-pathologic correlation: sclerotic bone lesions”. Radiographics 3 (2011): 941-961.