Intraoperative Technique for Evaluation of the Interosseous Ligament of the Forearm.

PURPOSE

To introduce a technique for the diagnosis of interosseous ligament (IOL) disruption based on lateral displacement of the radius after radial head resection and to determine the cutoff value of the lateral displacement for the diagnosis of disruption, the best elbow position for testing, and the diagnostic performance of the technique in different positions.

METHODS

We used 10 fresh-frozen cadavers. After resection of the radial head, a Steinman pin was placed into the radius medullary canal and used to mark the pin location on the capitellum. We applied 1 kg force to pull the proximal radius laterally and measured the displacement in full supination, neutral, and full pronation of the forearm with the elbow in extension and then in 90° flexion. All measurements were performed once with the IOL intact and again with it cut. To assess diagnostic efficacy, receiver operating characteristics curves were constructed. To determine the quality of the technique, we measured the area under the receiver operating characteristics curve for each position. We also determined the cutoff value to obtain the highest sensitivity and specificity.

RESULTS

The area under the curve of the test in extension-supination and flexion-supination showed that these positions were excellent for the diagnosis of IOL disruption. The cutoff value of 5.5 mm lateral displacement in extension-supination had 100% sensitivity and 90% specificity. In flexion-supination, the cutoff value of 9 mm had 100% sensitivity and 90% specificity for the diagnosis of IOL disruption.

CONCLUSIONS

This maneuver was reliable and accurate in cadavers with complete IOL disruption. It is likely that in an intraoperative setting, these results will be reproducible.

TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.