Prediction of the rotational state of the humerus by comparing the contour of the contralateral bicipital groove: Method for intraoperative evaluation

Background: Accurate reduction of rotational displacement for transverse or comminute fracture of humeral shaft fracture is difficult during operation. The purpose of this study was to evaluate the reliability of the bicipital groove as a point of reference for the prediction of the rotational state of the humerus on two dimensional images of C-arm image intensifier during operation for humeral shaft fractures. Materials and Methods: One hundred subjects, 62 male, 38 female, aged 22-53 years were recruited contralateral bicipital groove on the 45 degrees externally rotational standard anterior-posterior view recorded before surgery. Three observers, watched only contour of bicipital groove in monitor of C-arm image intensification with naked eye without looking at the subject and predicted rotational state of the humerus by comparing the contour of the opposite side of bicipital groove. The angle of discrepancy from real rotational position was then assessed. Results: The mean (SD), angular discrepancy between the neutral point and the predicted angle was 3.4(2.7). A value within 5 was present in 72% of cases. All observations were within 15. There was no interobserver variation (P = 0.47). The intraclass correlation coefficient (ICC) was 0.847. Conclusion: Contour of the bicipital groove on simple radiograph was a useful landmark. Comparing the contour of the bicipital groove in the 45 degrees externally rotational standard view bilaterally, was an effective method for reduction of rotational displacement of the humerus.