RESUMO
PURPOSE: The aim of this study was to measure the cortical thickness and bone density of the different parts of the bicipital tuberosity, to evaluate the importance of these variables on resistance to pulling out of distal biceps tendon reinsertion implants. METHODS: Sixteen cadaveric arms were used for this study. A multiple detector computed tomography was performed in each proximal radius. Bone thickness and density of anterior, posterior cortex and anterior trabecular bone were measured in proximal, medial and distal parts of the bicipital tuberosity. Statistical and concordance analyses of results were performed. RESULTS: In our specimens, the medial and distal parts of the anterior cortex and the anterior trabecular bone were thicker, mean 11.3 mm SD 2.72 and 11.17 mm SD 3.05, with a significant difference when compared to the proximal part; mean 10.3 mm SD 2.35, of radial tuberosity. The three posterior segments where all thicker compared to the anterior cortex (proximal 3.15 SD 1.31; medial 3.33 SD 1.5; distal 3.34 SD 1.43 mm), but without statistical differences between them. The measured bone density was equivalent in the three portions of the anterior cortex and trabecular bone [proximal 1924.63 SD 547.22; medial 1848.19 SD 538.59; distal 2100.47 SD 396.32 Hounsfield units (HU)]. The posterior cortex was denser compared to the anterior cortex and the anterior trabecular bone in all the segments (proximal 1962.63 SD 223.57; medial 1907.16 SD 232.08; distal 1987.06 SD 189.12 HU), but without statistical differences between the three parts. CONCLUSIONS: Based on the results of this anatomic study which have demonstrated that anterior cortex and anterior trabecular bone of the medial and distal regions of the bicipital tuberosity are thicker than proximal part, we postulate that these segments could give better pulling out resistance to monocortical implants. Our findings suggest that the strongest parts of the bicipital tuberosity are the proximal and medial parts of the posterior cortex. We can afford them drilling across the radius using a bicortical implant in the proximal and medial section of the radial tuberosity. Furthermore, we suggest that an increased margin of safety could be achieved to prevent injury to the posterior interosseous nerve, drilling the cortical hole in the proximal part of the radial tuberosity without losing resistance properties.
