Intra-medullary osteosclerosis of the tibia in children.

BACKGROUND: Intra-medullary osteosclerosis of the tibia is a rare condition characterised by chronic pain due to diaphyseal hyperostosis with no detectable triggering factor. The main differential diagnoses are stress fracture and osteoid osteoma. Of the few cases reported to date, most were in adults. The objective of this study was to assess paediatric patients with intra-medullary osteosclerosis to determine whether the first visit provides sufficient information to establish the diagnosis and rule out both osteoid osteoma and stress fracture, whether a biopsy is required, and which treatment is optimal. HYPOTHESIS: The diagnosis of intra-medullary osteosclerosis of the tibia can be made at the first visit. PATIENTS AND METHODS: Seven paediatric patients, 4 males and 3 females, with a mean age of 11 years, were included in this retrospective study. We evaluated the clinical features, findings from imaging studies (standard radiographs, computed tomography, magnetic resonance imaging, and bone scintigraphy), and treatment outcomes. RESULTS: At the first visit, all patients had a painful swelling at the middle of the shin and imaging study evidence of antero-lateral tibial cortical thickening extending into the medullary cavity; in 5 patients, a linear lucency was visible. No other bone abnormalities were seen. Treatments included non-operative measures, pinning, and nailing. None of these treatments provided permanent bone healing or pain relief, although transitory freedom from pain with or without radiological bone healing was achieved. DISCUSSION: Intra-medullary osteosclerosis of the tibia is rarely reported and therefore probably underdiagnosed. Distinctive characteristics of the cortical and endosteal thickening include location at the antero-lateral mid-diaphysis and, in some cases, the concomitant presence of a linear lucency that can provide the early diagnosis. The distinctive radiological features allow differentiation from a stress fracture. The management is challenging. LEVEL OF EVIDENCE: IV, retrospective observational study.