Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Trauma - Femur
Abstract number: 23771
A NEW METHOD OF DETERMINING DISTAL FEMORAL DEFORMITY
Irfan KHAN, Stephen NICOL, Roger ATKINS
Bristol Royal Infirmary, Bristol (UNITED KINGDOM)
Lower limb mal-alignment is a significant cause of degenerative change and
dysfunction. The standard technique available to determine the centre of rotation of
angulation (CORA), highlights it is difficult to assess and we found it to be inaccurate.
We devised a novel technique which accurately determines the CORA and extent of
distal femoral deformity, allowing accurate correction.Using standard leg alignment
views of the normal femur, the distal femoral metaphysis and joint line are stylized as
a block. A line bisecting the axis of the proximal femur is then extended distally to
intersect the joint. The angle between the joint and the proximal femoral axis and the
position (p) where the extended proximal femoral axis intersects the joint line are
calculated. These measurements can then be reproduced on the abnormal distal
femur in order to calculate the CORA and extent of the deformity, permitting accurate
correction.We examined the utility and reproducibility of the new method using 100
normal femora. -= 81 ± sd 2.5- As expected, correlated with femoral length (r=0.74).
P (expressed as the percentage of the distance from the lateral edge of the joint
block to the intersection) = 61% ± sd 8%. P was not correlated with Intra-and interobserver
errors for these measurements are within acceptable limits and
observations of 30-paired normal femora demonstrate similar values for and p on the
two sides.We have found this technique to be universally applicable and reliable in a
variety of distal femoral deformities.
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