Review Question - QID 9031

The maximum acceptable difference in rotational malreduction between the surgical and contralateral legs for femoral version is 15°. Therefore, answers 1 and 2 are correct.

Normal femoral neck anteversion is approximately 11-13°, with a normal range between 5-20°. The variation within the same patients can also be up to 15° difference between limbs. Current literature has shown that this 15° difference is well tolerated by patients, including when this has occured as a result of rotational malreduction following intramedullary nail fixation for a diaphyseal femur fracture.

Ayalon et al. aimed to compare the difference in femoral version (DFV) after intramedullary nailing performed by a trauma-trained and non-trauma trained surgeon. The mean post-operative DFV was 8.7° in these patients, compared to 10.7° in those treated by surgeons of other subspecialties. Post-operative version or percentage of DFV >15° did not significantly differ between these two groups.

Omar et al. studied the utility of pre-operative 'virtual reduction' of bilateral femoral fractures that were initially stabilized with external fixation. After external fixation, the mean rotational difference between both legs was 15.0° ± 10.2°. Following virtual reduction, the mean rotational difference between both legs was 2.1° ± 1.2°, after intramedullary nailing, compared to 6.1° ± 2.8° without the pre-operative tool.

Illustration A shows the typical CT scanogram cuts used to measure femoral version. Note, femoral version is obtained by measuring an angle between a line along the femoral neck and another line along the posterior condylar axis.

Incorrect Answers:
Answers 1-5: More than 15° difference in version between femurs is considered the upper limit for acceptable reduction.