Stress fractures of the femoral diaphysis in children: a report of 5 cases and review of literature.

The authors report five new cases of the stress fracture of the femoral diaphysis in children. These injuries usually occurred without a history of recent increase of activity. Recently regained normal activity after long-term immobilization and a fibrous cortical defect were predisposing factors. The periosteal reactions were usually identified in the initial radiograph and were not confined to the medial cortex of the distal femur; they might occur in any part of the femoral diaphysis, and also concomitantly on the multiple cortex. The atypical radiographic presentations frequently required MRI for differential diagnosis. Even though the MRI may be confusing to the inexperienced observer, it can lead to the diagnosis of a stress fracture with confidence, negating the need for biopsy. Clinicians should be aware of this diagnostic entity in the differential diagnosis of femoral diaphyseal lesions in children because the occurrence might be more common than reported. Serial simple radiographic examinations taken at intervals to look for the evidence of progressive fracture healing and the restriction of activity or immobilization may be an adequate approach for management.