Date: Thu, 28 Nov 2002 15:11:33 EST
Subject: CT Assessment of Femoral Malrotation
I have a 16 year old young woman with moderate clinical malrotation after a retrograde femoral nail for a minimally comminuted transverse fracture of the mid diaphysis. She is 5'4'' and about 250 pounds. I worked to assess rotation preoperatively off the uninjured side in anticipation of this problem, but still she is 25 degrees clinically externally rotated on the injured side. At the end of the case, I used the C-arm to look at both hips and both distal femurs to assess alignment, I thought I matched up the views pretty well. At this time I realize that my clinical exam is limited secondary to pain swelling, but he deformity is persistent. Does anyone know any reference of a reliable technique of CT assessment of rotational abnormalities that I can put to use??
Date: Thu, 28 Nov 2002 17:45:43 -0500
From: Bill Burman
Check the OTA Archives.
e.g. Saturday, October 23, 1999 Session IV, Paper #32, 8:38 a.m.
Date: Fri, 29 Nov 2002 16:42:45 -0600
From: Obremskey, William T
1) Strecker W, et al. CT measurement of Torsion angle of the lower
extremities. Unfallchirurg 1994 11:609
2) Strecker W et al. Correcting torsion after IMN of lower extremity. Unfallchirurg 1997 1:29-38
3)Grutzner P et al. Torsion after shaft fractures of the lowerextremities. Chirug 70(3): 276-284, 1999.
It has been a while since I looked at these, but the gist is that in #1 rotational profile can be assessed by measuring the difference b/t axial CT cuts through the femoral necks and the knees using femoral anteversion and slope of posterior condyles for measurements.
In #3 I believe the prospective study was done at a German experienced trauma center and they had 6-10% of patients have > 20% malrotation that were revised early w/ rotation and replacement of distal interlocking screw.
Date: Sat, 30 Nov 2002 09:41:44 EST
I did the CT at the suggestion of one of my partners who does the most trauma in town. I used the radiology PACS system to measure off the femoral neck and a reference line, and distally off the condyles. She is about 5 -10 degrees asymmetric, with increased ER on the affected side. The PACS system made this very easy to do..