Biomechanics (M Silva and P Zysset, Section Editors)

Current Osteoporosis Reports

, Volume 12, Issue 2, pp 189-193

Atypical Femoral Fractures, Bisphosphonates, and Mechanical Stress

  • Per AspenbergAffiliated withDepartment of Clinical and Experimental Medicine, Orthopedics, Faculty of Health Science, Linköping University Email author 
  • , Jörg SchilcherAffiliated withDepartment of Clinical and Experimental Medicine, Orthopedics, Faculty of Health Science, Linköping University

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Atypical fractures are stress fractures occurring in the femoral shaft and closely related to bisphosphonate use. We here discuss their radiographic definition and different putative etiologies, apart from mechanical stress. Long time reduction of skeletal remodeling because of bisphosphonate use is thought to allow time for the bone to deteriorate mechanically, resulting in reduced toughness. However, the risk of atypical fracture diminishes rapidly after cessation of treatment, which suggests more acute effects of bisphosphonate use. Microdamage normally accumulates at areas of high stress. Possibly, ongoing bisphosphonate use reduces the ability to resorb and replace areas of microdamage by targeted remodeling. This could lead to crack propagation beyond a point of no return, ending in macroscopic stress fracture.

Keywords

Atypical femoral fractures Bisphosphonates Bone remodeling Osteoporosis Bone fragility