The reliability of detecting screw penetration of the acetabulum by intraoperative auscultation.

Open reduction and internal fixation of the acetabulum frequently requires placement of screws in a blind fashion that risks penetrating the joint surface. While in the operative suite, direct visualization of the joint surface may not be possible, and fluoroscopy can be difficult to interpret. Auscultation of the hip with motion in a quiet room has been suggested as a useful adjunct to detecting screw penetration. Carrying that concept further, we auscultate the hip using a sterile esophageal stethoscope at the operating table and have found this to be a highly reliable method of detecting intraarticular screw placement. To test the reliability and reproducibility of this technique, an experiment was performed using inexperienced volunteers. In part I, two adult mongrel dogs were prepared. A screw was placed violating the hip joint in one dog, and in the other dog a screw was placed near but not penetrating the joint. Screw placement was verified under direct vision. Seventy-seven volunteers who did not know which hip was penetrated then auscultated both hips in random order and recorded their impressions after each hip was heard. After hearing both hips, 74 of 77 were able to identify the screw in the hip joint correctly; 69 were able to recognize the extraarticular screw correctly. In part II, both hips of a human cadaver were exposed and dislocated. In one hip, a screw was placed that tangentially violated the joint, and in the same area of the contralateral hip a screw was placed that did not penetrate the joint surface.(ABSTRACT TRUNCATED AT 250 WORDS)