Abstract
Background
During cephalomedullary nail stabilisation of subtrochanteric femoral fractures, damage to the distal anterior femoral cortex by the nail is a recognised cause of periprosthetic fracture. Currently available cephalomedullary devices vary widely in anteroposterior curvature, though all are less curved than the mean anatomic human femur. This study tests the hypothesis that a cephalomedullary device with greater anteroposterior curvature will achieve a more favourable position in the distal femur, with greater distance of the nail tip from the anterior cortex, and therefore lower risk of cortical damage.
Methods
Retrospective analysis of postoperative radiographs from patients undergoing subtrochanteric femoral fracture stabilisation with either a)Stryker Long Gamma Nail (radius of curvature 2.0m, 19 patients) or Synthes long PFNα (1.5m, 19 patients) was performed. Distance from the anterior femoral cortex to the anterior part of the distal nail was measured, using the known diameter of the nail as a radiographic size marker.
Results
The mean distance from nail to anterior cortex was significantly higher for the PFNα group than the Long Gamma Nail Group (7.31mm vs 4.73mm, unpaired t-test p=0.003).
Conclusion
Using a cephalomedullary device with a tighter anteroposterior curvature resulted in a distal nail position better-centred in the sagittal plane, thus decreasing the risk of anterior femoral cortex damage and periprosthetic fracture. We strongly recommend consideration of anteroposterior curvature when choosing a cephalomedullary nailing system.
