Atypical Femur Fractures

Atypical Femur FracturesAtypical femur fracture xray





Lateral femoral shaft




Stress fractures


Associated with long term bisphonate use




Black et al. NEJM 2020

- reduction of hip fracture risk v risk of atypical femur fracture

- 10 year period

- 196,000 women > 50, 277 atypical femur fractures

- differences dependent on race

- in white women, over 3 years prevented 149 hip fractures and caused 2 atypical femur fractures

- in asians, over 3 years prevented 91 hip fractures and caused 8 atypical femur fractures


Dell et al. Osteoporosis International 2018

- recommendations for drug holidays

- consider DEXA scan or other imaging every 3 - 5 years

- look for any focal or generalised lateral femoral cortical changes




Will typically have thigh pain for some times






Lateral femur

- tension side

- see thickening of the lateral cortex

- beaking

- most common in the subtrochanteric region, but can be in shaft


Atypical femur fracture xrayAtypical femur fracture



Atypical femur fracture CTAtypical femur fracture CT 2


Incomplete Fracture


Stress Fracture Lateral


Complete fracture


Femoral stress fracture






Koh et al. Bone Joint J 2017

- systematic review

- nonoperative treatment of complete fractures failed in 50%, and surgery achieved union in 97%

- complete fractures - IMN nonunion rate 12.9%, plate fixation nonunion rate 31%

- must discontinue bisphonates

- mean time to union 7 months post surgery


Nail aptypical 1Nail atypical 2


Femoral stress fractureFemoral Stress Fracture IMN




Refer to osteoporosis

- cease bisphosphonates

- treat with calcium and vitamin D

- consider teriparatide


Compression Stress Fractures


Medial femur

- rare

- usually unite



Stress Fracture Medial