Linear relationship between lateralization of the bicipital groove and humeral retroversion and its link with the biepicondylar humeral line. Anatomical study of seventy cadaveric humerus scans

International audienceIntroduction Morphological studies of the humerus have shown that the position of the bicipital groove varies with the individual and the retroversion of the humeral head. Depending on the authors, these two parameters are independent or associated. This study evaluated the relationship between the humeral head axis and its retroversion and the bicipital groove relative to the humeral biepicondylar line.Materials and methods Seventy cadaveric humeri were scanned to obtain 3D reconstructions. Views of the 3D reconstruction from above showed the bicondylar line, the bicipital groove and the humeral head on a single image. After measuring the humeral retroversion angle and the bicipital groove angle relative to the bicondylar line, we assessed the relationship between these two angles with Pearson's correlation coefficient.Results Pearson's correlation coefficient indicated a significant linear correlation between the angle of the groove and the angle of humeral retroversion based on the 70 cadaveric humeral bones (the p-value was 7.5(10) (7), the correlation coefficient was -0.5515, and the 95% confidence interval was (-0.6962; -0.3636)). Our study thus demonstrates that the less lateralized the bicipital groove is, the greater the humeral retroversion will be.Conclusion We demonstrated a linear relationship between humeral head retroversion and bicipital groove lateralization. Within our reliability interval, this relationship can be used in clinical practice to evaluate retroversion without resorting to CT of the entire humerus