Bisphosphonate-Associated Atypical Femoral Fractures: A Description of Surgical Techniques in the Revision Fixation Setting With an Emphasis on Avoiding Varus Malalignment: A Two-Case Report.

INTRODUCTION

Atypical femoral fractures (AFFs) are insufficiency fractures of the lateral femoral cortex and represent a rare but significant complication of long-term bisphosphonate or denosumab therapy. Our report explores the surgical techniques utilised to avoid varus malalignment in these two complex cases, both of which fulfilled the American Society for Bone and Mineral Research (ASBMR) criteria for AFFs.

CASE PRESENTATION: Case 1 presents a woman in her early 60s with over 8 years of bisphosphonate use, who developed simultaneous AFFs. She underwent bilateral internal fixation with cephalomedullary nails. This was followed by revision surgery and a valgus correction for right femoral fracture nonunion.Case 2 presents a man in his late 60s with prior exposure to bisphosphonates and denosumab (< 7 years), who sustained a left AFF. Initial cephalomedullary nailing was complicated by nonunion and hardware failure, necessitating revision with a valgus correction.

CONCLUSION

Our cases emphasise the importance of recognising symptoms during follow-up assessments and provide a detailed account of the surgical techniques employed in the revision fixation of AFFs, with a particular emphasis on achieving valgus alignment, maintaining a medial entry point and avoiding varus malalignment to optimise mechanical stability, reduce the risk of postoperative nonunion and promote fracture healing.