Oral Presentation 33rd ASM of the Australian & New Zealand Bone & Mineral Society 2023

Does long-term antiresorptive administration lead to atypical fractures at other skeletal sites excluded from the ASBMR atypical femur fracture (AFF) case definition? A systematic review (#37)

Lucy Collins 1 , Alec Ronan 1 , Evelyn Hutcheon 2 , Peter R Ebeling 3 4 , Vivian Grill 1 5 , Hanh H Nguyen 1 3 4 5
  1. Department of Endocrinology and Diabetes, Western Health, Melbourne, Victoria
  2. Western Health Library Service, Melbourne, Victoria
  3. Department of Medicine, School of Clinical Sciences, Monash University, Melbourne, Victoria
  4. Department of Endocrinology, Monash Health, Melbourne , Victoria
  5. Department of Medicine, University of Melbourne, Parkville, Victoria, Australia

Osteoporosis affects > 1.3 million Australians. Bisphosphonates and denosumab are approved treatments for osteoporosis with the rare complications of jaw osteonecrosis and AFFs. Cases of AFFs were first reported in 2005, highlighting a state of suppressed bone turnover on biopsy (1). In 2010 and 2013, an American Society of Bone and Mineral Research (ASBMR) Task Force proposed a case definition for these atypical fractures affecting the femoral diaphysis (2, 3). Subsequently, reports of similar atypical fractures at other skeletal sites have been published.

 

Aim

We aimed to systemically identify cases of atypical fractures, excluded from the ASBMR AFF case definition in patients receiving anti-resorptive medication (duration > 3 years). 

 

Method

A structured search of electronic databases (PubMed, Medline, Embase, Cochrane, Web of Science) and hand-searching of conference abstracts/reference lists was completed. All full-text articles written in English describing atypical fractures were screened for: 1) cases of atypical fractures, excluded from the ASBMR AFF case definition in patients (aged > 18 years) receiving long-term antiresorptives, 2) cases published 2005 – 2023.

 

Results

7954 citations were identified. 65 articles fulfilled the inclusion criteria. Fractures were more common in females (112/120, 93%). Most frequent fracture sites included the ulna (n=32), tibia (n=12), pelvis (n=10), vertebral pedicle (n=8), sacrum (n=6) and femoral neck (n=5). One atypical fracture was reported in a monogenetic bone disorder (hypophosphatasia). Fractures were commonly atraumatic, with prodromal pain and typically transverse, non-comminuted with evidence of cortical thickening and sclerosis. Non-union was more frequent following conservative management. In most cases, anti-resorptive medication was ceased (41/47, 87%).

 

Conclusion

Atypical fractures at sites other than the femoral diaphysis in patients receiving long-term anti-resorptive treatment are important to recognise and may provide insights into the pathogenesis of AFF. A review of the current AFF case definition could be undertaken to include other skeletal sites.

  1. Odvina CV, Zerwekh JE, Rao DS, et al. Severely suppressed bone turnover: a potential complication of alendronate therapy. J Clin Endocrinol Metab. 2005;90(3):1294-301.
  2. Shane E, Burr D, Abrahamsen B, et al. Atypical subtrochanteric and diaphyseal femoral fractures: second report of a task force of the American Society for Bone and Mineral Research. J Bone Miner Res. 2014;29(1):1-23.
  3. Shane E, Burr D, Ebeling PR, et al. Atypical subtrochanteric and diaphyseal femoral fractures: report of a task force of the American Society for Bone and Mineral Research. J Bone Miner Res. 2010;25(11):2267-94.