A screw that is placed with a greater than 15° divergence results in loss of fixation. The screw appears to be normal from the anterior notch view, but on the posterior view of the sawbones model the screw has cut through the graft, and exited posteriorly (Fig. 9.24). This example is not only divergent, but has cut the bone plug off the graft.
The solution is to recognize the problem early and change the screw angle direction. It also helps to flex the knee 20° more than the tunnel angle.
To prevent divergent screws, use a screw guide wire in the tunnel.
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