Contralateral atypical femoral fracture following a single dose of denosumab after incomplete teriparatide therapy in a patient with long-term bisphosphonate exposure: A case report

Atypical femoral fractures (AFFs) are rare but serious complications of prolonged antiresorptive therapy. While bisphosphonate-associated AFF is well documented, the risk associated with sequential teriparatide and antiresorptive therapy remains poorly characterized. This case demonstrates that contralateral impending AFF can develop after a single dose of denosumab in a bisphosphonate-pretreated patient, despite confirmed radiological normality at the time of the index fracture. Negative contralateral imaging should not provide reassurance in high-risk patients, and vigilance is warranted when considering antiresorptive therapy transitions following incomplete anabolic treatment.