Progression of bisphosphonate-associated impending atypical femoral fracture despite prophylactic cephalomedullary nailing: A case report and review of literature

Rare Presentation of Atypical Fractures in a Patient of Autoimmune Polyglandular Syndrome - A Case Report

Introduction

An atypical bone fracture is a complete or partial discontinuity of bone which occurs without sufficient trauma. Autoimmune polyglandular syndromes are complex conditions characterized by the simultaneous presence of at least two autoimmune-mediated endocrinopathies. These syndromes exhibit considerable heterogeneity in their manifestations and typically unfold sequentially, with a significant time gap between the onset of the initial and subsequent glandular autoimmune diseases. In this article, we report a case of bilateral subtrochanteric atypical fractures in a patient with autoimmune polyglandular syndrome. This case scenario has not been reported in the literature so far to the best of our knowledge.

Case Report

A 37-year-old female patient presented at a tertiary care center in a metropolitan city with complaints of pain in both hips and the upper thigh. The patient faced difficulty walking and was unable to do so due to severe pain. Notably, there was no history of a fall or trauma. A radiographic examination revealed bilateral subtrochanteric atypical fractures. Upon further investigation, the patient was also found to be having hypothyroidism, hypoparathyroidism, pancytopenia, and an autoimmune disorder. The patient received a diagnosis of Autoimmune polyglandular syndrome with bilateral subtrochanteric atypical fractures. Treatment involved a comprehensive approach, including thyroxine for hypothyroidism, low-dose steroids, immunosuppressive agents, calcium supplementation, parathyroid hormone, and transfusion of blood and blood products. Due to the fractures being extra-articular, incomplete, and undisplaced, a conservative management approach was adopted.

Conclusion

The occurrence of atypical and pathological fractures, particularly when bilateral or recurrent, necessitates a comprehensive evaluation to determine the root cause. It is imperative to address the underlying etiology thoroughly in every patient. Neglecting to do so may lead to a recurrence or insufficient resolution of the pathology. In instances where two or more endocrine organs are involved, consideration should be given to autoimmune polyglandular syndrome as a potential diagnosis.

The enigma of atypical femoral fractures: A summary of current knowledge

Atypical femoral fractures (AFF) are stress or ‘insufficiency’ fractures, often complicated by the use of bisphosphonates or other bone turnover inhibitors. While these drugs are beneficial for the intact osteoporotic bone, they probably prevent a stress fracture from healing which thus progresses to a complete fracture.

Key features of atypical femoral fractures, essential for the diagnosis, are: location in the subtrochanteric region and diaphysis; lack of trauma history and comminution; and a transverse or short oblique configuration.

The relative risk of patients developing an atypical femoral fracture when taking bisphosphonates is high; however, the absolute risk of these fractures in patients on bisphosphonates is low, ranging from 3.2 to 50 cases per 100,000 person-years.

Treatment strategy in patients with AFF involves: radiograph of the contralateral side (computed tomography and magnetic resonance imaging should also be considered); dietary calcium and vitamin D supplementation should be prescribed following assessment; bisphosphonates or other potent antiresorptive agents should be discontinued; prophylactic surgical treatment of incomplete AFF with cephalomedullary nail, unless pain free; cephalomedullary nailing for surgical fixation of complete fractures; avoidance of gaps in the lateral and anterior cortex; avoidance of varus malreduction.

Cite this article: EFORT Open Rev 2018;3:494-500. DOI: 10.1302/2058-5241.3.170070.