Atypical fracture of the tibial diaphysis associated with bisphosphonate therapy: a case report

Atypical subtrochanteric femoral shaft fractures (AFFs) have recently emerged as a potential long-term complication of bisphosphonate therapy. In 2010, the American Society for Bone and Mineral Research (ASBMR) Task Force published a definition for AFF consisting of 5 major and 7 minor features. Little attention has so far been paid to the possibility that bisphosphonate-associated atypical fractures may also involve the diaphysis of other long bones. We report here the case of a patient on long-term bisphosphonate therapy who presented a diaphyseal tibial insufficiency fracture fulfilling all the major criteria (except for the location), and a number of the minor criteria of an atypical fracture. Our case report suggests the need for greater awareness of the possibility of atypical fractures at other sites, particularly in weight-bearing long bones other than the femur, and suggests that long-term bisphosphonate therapy may also contribute to the occurrence of these atypical fractures.