Factors influencing neck anteversion during femoral nailing: a retrospective analysis of 220 torsion-difference CTs.

BACKGROUND:
Rotational malalignment is a well-known complication following intramedullary nailing of femoral shaft fractures. The hypothesis of this study is that various modifiable factors, such as position on the surgical table or nailing technique, influence the incidence of torsional abnormalities.

METHODS:
For this retrospective study, we analysed the data of 220 consecutive patients with femoral shaft fractures and postoperative torsion-difference computed tomographies (CTs), performed from 2001 to 2009 in our institution. Mean age of the patients was 33±15 years. Average delay to surgery was 8±11 days. The average postoperative neck anteversion difference between both sides was 11±8°. A p value < 0.05 was considered to be statistically significant.

RESULTS:
The average postoperative neck anteversion difference between both sides was not significantly affected from the position of the patient on the surgical table (supine or lateral, p=0.698), the delay till surgery (p=0.989), the nailing technique (antegrade or retrograde, p=0.793; reamed or unreamed, p=0.930), the type of the implant (p=0.885) and the experience of the surgeon (p=0.055). Furthermore, the learning curve regarding this complication was long and not predictable.

CONCLUSIONS:
We could not identify any risk factors that are associated with an increased incidence of torsional deformities, and thus our hypothesis could not be confirmed. The inability to identify such risk factors renders the prevention of this complication particularly problematic. The invention of new techniques for better intra-operative control of the torsion is probably the only solution to further reduce the incidence of postoperative malrotational deformities.