Clinical assessment of cancellous bone content in the humeral head

Abstract

Objective To measure the cancellous bone contents at different parts of the humeral heads of different ages and genders for data helpful for humeral head fixation.Methods Thirty-six patients with proximal humeral fracture were selected for this study who had been treated at our department with locking proximal humerus plate from June 2008 to April 2010.They were 18 men and 18 women,aged from 20 to 86 years (average,51.6 years).They were grouped according to age:group A ( ＜ 40 years),group B (40 to 60 years),and group C (＞ 60 years).A GE Sensation 16 CT scanner (GE Healtbcare,USA) was used to scan both of their affected and healthy humeral heads preoperation,with slices one mm thick.The bone density of cancellous bone was assessed by the CT value expressed in Hounsfield units.The maximum,minimum,and mean CT values were calculated for the cancellous bone in the humeral head in each image.CT images were processed by computer with custom software (Xiphoid 1.3,Image J 1.4g and Image-Pro Plus 6.0).All the data were analyzed with SPSS16.0.Results We found 4 weak point.s at the cortical bone of proximal humerus,correspondent with the 4 clinic CT types of proximal humeral fracture.The cancellous bone was the densest in the medial humeral head.The mean cancellous bone content was significantly lower in group C than in group A and B( P ＜ 0.05).There was a significant difference between men and women in group A in the BMD of cancellous bone ( t =4.744,P =0.001 ).Conclusions The cancellous bone content in the humeral head is related with age and gender.Since there is more cancellous bone in the medial part than in other parts of the humeral head,it is a reliable part for humeral head fixation. Key words: Humeral fracture, proximal; Bone density; Age groups