The Journal of Bone and Joint Surgery, Vol 73, Issue 5 726-733, Copyright © 1991 by Journal of Bone and Joint Surgery, Inc
Treatment of the unstable intertrochanteric fracture. Effect of the placement of the screw, its angle of insertion, and osteotomy
BD Den Hartog, E Bartal and F Cooke
Department of Surgery, University of Kansas School of Medicine-Wichita.
We created unstable intertrochanteric fractures with a large posteromedial
defect in eighteen pairs of fresh-frozen femora from cadavera, and used the
femora to evaluate the stability of six combinations of treatment with
sliding compression screws and sideplates. The variables that were tested
were high (150-degree) angle plates compared with low (130-degree) angle
plates, the position of the lag-screw in the femoral head and neck (in the
center of the head as seen on both anteroposterior and lateral
roentgenograms compared with posteroinferiorly), and whether or not medial
cortical contact had been re-established with a limited osteotomy of the
greater trochanter. The femora were loaded to the point of failure. The
mode of failure, maximum load to failure, and bending rigidity of each
method of fixation were measured. Of the six types of treatment, the use of
a 150-degree-angle plate, position of the lag-screw in the center of the
head as seen on both anteroposterior and lateral roentgenograms, and
osteotomy of the greater trochanter resulted in the highest mean load to
failure and the greatest rigidity. Over-all, re-establishment of medial
cortical contact by means of an osteotomy of the greater trochanter
significantly improved the mean load to failure and the rigidity of the
fixation. The higher-angle plate, although more difficult to insert,
increased the mean load to failure but had no effect on rigidity. The
position of the lag-screw (in the center of the head as seen on both
anteroposterior and lateral roentgenograms or posteroinferiorly) had no
bearing on the mean load to failure, but it significantly affected the mode
of failure.