Three-dimensional analyses of proximal humeral fractures using computed tomography with multiplanar reconstruction: early stability of fixation after osteosynthesis in relation to preoperative bone quality

The purpose of this study was to evaluate the relationship between the bone quality of the humeral head measured by CT multiplanar reconstruction images (MPR) and the stability of nail or plate fixation and to compare the clinical outcomes of these procedures in patients with proximal humeral fractures. Thirty-six consecutive patients (nail group: n = 18, plate group: n = 18) were investigated. In nail group, 14 cases were classified as two-part fractures, three cases were classified as three-part fractures and one case was classified as four-part fractures. In plate group, three cases were classified as two-part fractures, nine cases were classified as three-part fractures and six cases were classified as four-part fractures. Both clinical and radiological outcomes were assessed. In addition, the percentage of trabecular bone volume of the humeral head was calculated using preoperative CT-MPR images. Three patients in the nail group underwent reoperation. In contrast, no patients in the plate group underwent reoperation. In nail group, six of 18 (33 %) patients demonstrated poor results (three underwent reoperation, and three had varus displacements >10º) and had bone volume percentages (axial image) that were significantly lower than those observed in the patients with good results. The cutoff point of trabecular bone volume required to obtain satisfactory results after surgical treatment using intramedullary nail was 78 %. The results of this study suggest that the bone volume of the humeral head calculated using CT-MPR images provides useful information, in addition to the type of fracture, when selecting fixation devices for osteosynthesis of proximal humeral fracture.