78 - Freie Mitteilung
16. Mai 2019, 17:30 - 19:00, Sopra 3, 4. OG
Simple correction technique of femoral malrotation after PFN-A osteosynthesis of trochanteric fracture
K. Pavotbawan, P. Stillhard, C. Sommer, Presenter: K. Pavotbawan (Chur)
Malrotation after intramedullary nailing in femoral shaft fractures are well known. But malrotation after nailing of trochanteric fractures is, in our view, an underestimated problem. During surgery the axial alignment can easily be evaluated by fluoroscopy in both planes. But the torsional alignment is difficult to assess especially with the patient placed on the traction table. In the literature a malrotation after PFNA is described in up to 25% of the cases. A revision with replacement of the blade, especially in patients with poor bone quality, may result in a reduced stability. To our knowledge there is no publication till to date to give a treatment pathway for this problem. We developed a rather easy technique to derotate a malrotated femur after PFNA fixation.
The basic idea of our technique is to leave the usually well placed blade in situ in the femoral head, just rotating the distal main fragment around the nail. To be able to do this, a small U-shaped osteotomy with a chisel is performed in the femoral cortex just anterior of the entry site of the blade. The length (l) of this osteotomy can be calculated, following the formula: l = d x π x α/360 (d=diameter of femur, α=angle of malrotation). Then the distal locking bolt is removed, the leg derotated externally and finally locked again. The procedure is controlled by two Schanz’screws separately inserted in both main fragments angulated to each other in the angle “α“.
Since 2014 three patients were detected with a clinically relevant malrotation after PFNA for trochanteric fracture. All patients had an internal malrotation from 30 to 40 degrees confirmed and measured by CT scan. All of them were successfully revised in the above described technique 5 to 9 days after initial fixation. The postoperative course was in all patients without complication.
First, we believe that malrotation after trochanteric fracture fixation is an underestimated problem. And second our method is a simple salvage procedure for malrotated trochanteric fractures after PFNA, leaving the blade in situ in the femoral head.