Three-dimensional morphological analysis of acromioclavicular joint in patients with and without subacromial erosion after hook plate fixation.

Objective To investigate the role of acromioclavicular joint morphology in the presence of subacromial erosion after hook plate fixation. Methods We retrospectively analyzed the clinical data of 36 patients (17 men, 19 women; mean age, 48.7 years; range, 21-76 years) treated with hook plate fixation for distal clavicular fractures (n = 20) or acromioclavicular joint dislocation (n = 16) from August 2011 to March 2013. The patients were divided into two groups: the subacromial erosion group (18 patients) and the normal group (18 patients). Differences in multiple anatomical parameters between the two groups were measured and compared. Results The distal clavicle-acromion angle was significantly larger in the subacromial erosion group (mean, 51.37° ± 5.59°) than in the normal group (mean, 44.20° ± 3.83°), as was the distal clavicle-coronal angle (mean, 25.44° ± 2.51° vs. 21.67° ± 4.06°, respectively). The thickness of the acromion was significantly different between men and women (9.72 ± 1.13 vs. 8.16 ± 1.89 mm, respectively). Conclusion The results of this study indicate that the distal clavicle-acromion angle and distal clavicle-coronal angle are closely correlated with the occurrence of subacromial erosion after hook plate fixation.

Expression of vascular endothelial growth factor and matrix metalloproteinase-9 in sacral chordoma.

Sacral chordoma is a vessel-rich and infiltrative tumor, but the fundamental knowledge of its biological behavior remains unknown. This study was designed to investigate the expression levels and contributions of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) in the angiogenesis and recurrence of sacral chordoma and their correlations. An immunohistochemical method was used to investigate the expression of VEGF, MMP-9, and microvascular density (MVD) in 36 patients with sacral chordoma. Their differences in expressions were statistically analyzed and their correlations with angiogenesis and recurrence were evaluated. The mean MVD of sacral chordomas was significantly higher than that of the adjacent normal tissues (P = 0.033). Immunoreactivity for VEGF and MMP-9 was significantly higher in sacral chordoma tissues than in adjacent normal tissues (P = 0.008, P = 0.005). The mean MVD of VEGF and MMP-9 were statistically higher in positive group than in negative group (P = 0.015, P = 0.004), respectively . Moreover, a significant correlation was found between the VEGF and MMP-9 (P = 0.002). The log-rank test revealed that continuous disease-free survival time (CDFS) was significantly shorter in the MMP-9-positive group than in the MMP-9-negative group (P = 0.019), but the difference in the VEGF-positive group and the VEGF-negative group was not statistically significant (P = 0.938). Our data suggest that VEGF and MMP-9 might act with a synergistic effect and can positively regulate the angiogenesis in sacral chordoma. Positive expression of MMP-9 might indicate the local recurrence of sacral chordoma. The result suggests that some specific drugs which inhibit VEGF, MMP-9, or their receptors may have a good therapeutic effect for sacral chordoma.