RigidFix femoral fixation: a test for detecting inaccurate cross pin positioning.

Abstract

The RigidFix Cross Pin System (DePuy Mitek, Raynham, MA) is a popular technique for femoral fixation of graft in ACL reconstruction. In some cases, though, cross pins miss the femoral tunnel resulting in inadequate proximal graft fixation. We present a simple test to detect the incorrect placement of cross pins. The pinholes are drilled through the guide frame, leaving 2 sleeves for cross pins insertion. The manufacturer's recommendations, at this stage, are to reinsert the femoral tunnel guidewire, remove the guide frame, and insert the graft without verifying accurate pinhole positioning. We reinsert the femoral tunnel guidewire without removing the guide frame, and a second guidewire is introduced through each of the sleeves in turn. In case of appropriate pinhole placement, the 2 guidewires will meet in the cannulated rod of the guide frame and the surgeon will have the metal-to-metal feeling. If the pinhole misses the femoral tunnel, the 2 guidewires will not meet and the surgeon will not have the metal-to-metal feeling. In our practice, 9 cases of inaccurate pinhole placement were detected with this test and verified by direct vision of the femoral tunnel with the arthroscope. We find this test simple, reliable, and not time consuming.