Measurement of volumetric bone mineral density in proximal humerus using quantitative computed tomography in patients with unilateral rotator cuff tear.

BACKGROUND: The first purpose of this study was to reveal the clinically important region-specific volumetric bone mineral density (vBMD) of the proximal humerus in patients with unilateral rotator cuff tear (RCT), and the second was to evaluate the relationship between vBMD of the proximal humerus and BMD of the hip and lumbar spine measured using conventional dual-energy X-ray absorptiometry. Finally, we assessed whether any clinical factor could predict local osteoporosis of the proximal humerus. METHODS: The study enrolled 65 patients who underwent arthroscopic repair of a unilateral RCT between April 2010 and July 2011 and had computed tomography scans of bilateral proximal humeri. Considering the suture bridge technique for RCT repair to be the leading treatment, region-specific BMD was measured in 7 volumetric blocks in the proximal humerus. Image and quantification processing was used to calculate the vBMD of each block. RESULTS: The vBMD values in all 7 blocks of the symptomatic shoulder were significantly lower than those of the asymptomatic contralateral shoulder (P < .05). Regardless of RCT, the greater tuberosity showed significant location-dependence in vBMD value; that is, the vBMD value was the highest in the posterolateral portion and the lowest in the medial portions. No significant correlation was found between vBMD of the greater tuberosity and clinical factors except female gender. CONCLUSION: The present study demonstrated the regional and bilateral differences in vBMD within the greater tuberosity in patients with unilateral RCT. Aside from female gender, no other clinical factors presented as risk factors for a higher possibility of osteoporosis.