Subtrochanteric Femoral Fractures in Patients Receiving Long-Term Alendronate Therapy: Imaging Features

Abstract

Subtrochanteric femoral fractures associated with long-term alendronate therapy present with minimal trauma, may be chronic, and when incomplete may be missed. The characteristic imaging features include initial involvement and focal thickening of the lateral cortex, transverse orientation, medial beak, and superior displacement and varus angulation at the fracture site.

Healing Delayed But Generally Reliable After Bisphosphonate-associated Complete Femur Fractures Treated with IM Nails

“…These observations are consistent with the belief that the presence of such pain, associated with a history of bisphosphonate therapy, may serve as an indicator of impending fracture [28]. Radiographs of these atypical femoral fractures have also shown consistent characteristics such as transverse or short oblique fracture, focal lateral cortical thickening, the presence of a medial beak, defined as a spiked appearance of the medial femoral cortex, and relative lack of comminution [4]. Those who display clinical or radiographic symptoms of incomplete bisphosphonateassociated femur fractures should be counseled about the potential risk of sustaining a complete fracture and prophylactic measures to prevent fracture completion [8].…”

“…Radiographs before fracture completion and displacement show focal lateral cortical thickening with or without a visible, incomplete fracture line [4,26]. In addition, these injuries are secondary to low-energy or minimal to no trauma mechanism, unlike other proximal femoral fractures, which are typically associated with major trauma [4]. When complete and displaced, these atypical subtrochanteric and diaphyseal femoral fractures have characteristic radiographic features such as the presence of a transverse or short oblique fracture line, medial spike, focal lateral cortical thickening, and relative lack of comminution, that differ from typical femur fractures but are usually treated with a similar surgical procedure as used for treating conventional femoral fractures [4].…”

“…Patients who sustain these fractures typically report prodromal thigh pain weeks to months before sustaining fractures. Radiographs before fracture completion and displacement show focal lateral cortical thickening with or without a visible, incomplete fracture line [4,26]. In addition, these injuries are secondary to low-energy or minimal to no trauma mechanism, unlike other proximal femoral fractures, which are typically associated with major trauma [4].…”

Impending atypical femoral fractures due to prolong bisphosphonate use – case report and literature review

“…In the discussed case, it showed increased, focal radioactive marker uptake on the lateral cortex of both proximal femurs with thickening of cortices. Similar changes were described by Chan S. et al [15]. This finding may testify that we are dealing with incomplete fatigue fracture, often associated with prolonged BPs use.…”

Bisphosphonate-Associated Atypical Subtrochanteric Femur Fracture

“…Bisphosphonates work by inducing osteoclast apoptosis (2,3). A known risk of long-term bisphosphonate therapy is a unique fracture known as an atypical subtrochanteric femur fracture.…”