Treatment strategy for atypical ulnar fracture due to severely suppressed bone turnover caused by long-term bisphosphonate therapy: a case report and literature review

BACKGROUND: Atypical fractures may occur due to the combined effect of severely suppressed bone turnover (SSBT) caused by long-term bisphosphonate treatment and chronic repetitive bone microdamage. Atypical fracture of the ulna due to SSBT is a rare entity; there is no standardized treatment strategy for this condition. We successfully treated a patient with atypical fracture of the ulna. Herein, we present this patient, review the relevant literature, and discuss the treatment strategy. CASE PRESENTATION: An 84-year-old woman presented with atypical fracture of the left ulnar shaft due to SSBT. She had a history of bisphosphonate therapy (ibandronate and alendronate) since more than 10 years; her bone turnover was severely suppressed. We performed open reduction and internal fixation (ORIF) using dual plate with some additional treatments. These included drilling and decortication, use of autogenous bone graft, low-intensity pulsed ultrasound (LIPUS) treatment, and administration of teriparatide. Finally, bone union was observed at 11 months after surgery. CONCLUSIONS: Based on the literature review and our experience with this case, ORIF alone may not be adequate to achieve bone union; drilling, decortication, and use of cancellus bone graft is important to achieve favorable outcomes. Administration of teriparatide and LIPUS may facilitate early bone union, although further studies are required to provide more definitive evidence. Furthermore, ORIF using dual plate may help avoid implant failure owing to the long time required for bone union.