Clinical correlates of atypical femoral fracture.

Abstract

Reports of atypical femur fracture in bisphosphonate-exposed women have prompted interest in characterizing the clinical profiles of these patients. Among women age ≥60 years with hip or femur fracture during 2007-2008, we identified 79 with low-trauma subtrochanteric or femoral shaft fracture. Radiographic images were reviewed to assign fracture pattern and distinguish atypical femur fracture from non-atypical femur fracture. Differences in clinical characteristics and pharmacologic exposures were compared. Among 79 women (38 subtrochanteric and 41 femoral shaft fracture), 38 had an atypical femur fracture. Compared to those with a non-atypical femur fracture, women with atypical femur fracture were significantly younger (74.0 vs 81.0 years), more likely to be Asian (50.0 vs 2.4%) and to have received bisphosphonate therapy (97.4 vs 41.5%). Similarly, the contralateral femur showed a stress or complete fracture in 39.5% of atypical femur fractures vs 2.4% non-atypical femur fracture, and focal cortical hypertrophy of the contralateral femur in an additional 21.1% of atypical cases. Women suffering atypical femur fractures have a markedly different clinical profile from those sustaining typical fractures. Women with atypical femur fracture tend to be younger, Asian, and bisphosphonate-exposed. The high frequency of contralateral femur findings suggests a generalized process.