Treatment guidelines for atypical femoral fractures associated
with bisphosphonates have not been established. We conducted a systematic
review of the treatment of atypical femoral fractures first, to
evaluate the outcomes of surgical fixation of complete atypical fractures
and secondly, to assess whether prophylactic surgery is necessary
for incomplete atypical fractures. Case reports and series were identified from the PubMed database
and were included if they described the treatment of atypical femoral
fractures. In total, 77 publications met our inclusion criteria
and 733 patients with 834 atypical complete or incomplete femoral fractures
were identified.Aims
Materials and Methods
In an adult man the mean femoral anteversion angle measures approximately 15°, for which the reasons have never been fully elucidated. An assortment of simian and quadruped mammalian femora was therefore examined and the anteversion angles measured. A simple static mathematical model was then produced to explain the forces acting on the neck of the femur in the quadruped and in man. Femoral anteversion was present in all the simian and quadruped femora and ranged between 4° and 41°. It thus appears that man has retained this feature despite evolving from quadrupedal locomotion. Quadrupeds generally mobilise with their hips flexed forwards from the vertical; in this position, it is clear that anteversion gives biomechanical advantage against predominantly vertical forces. In man with mobilisation on vertical femora, the biomechanical advantage of anteversion is against forces acting mainly in the horizontal plane. This has implications in regard to the orientation of hip replacements.
