Assessment of bone quality in the proximal humerus by measurement of the contralateral site: a cadaveric analyze

Introduction: The presence of osteoporosis decreases the success of osteosynthesis, especially in the proximal humerus. Estimation of the bone mineral density (BMD) at the fracture site could aid in the decision making for surgical treatment and potential implant choice with regard to the individual bone properties. BMD measurement at a fracture site is prone to inaccuracies and alternative measurement sites need to be identified. In the case of a proximal humerus fracture, promising alternative measurement sites are at the same contralateral or at a different ipsilateral location. The aim of this study was to determine if the BMD for the humeral head can be predicted by BMD measurements from the ipsilateral distal humerus or the contralateral proximal humerus. Material and methods: Cancellous BMD values were obtained from 88 paired human cadaver humeri (age 75.8±13.5 years) at the humeral head and at the distal metaphyseal area by pQCT. Correlations between BMD values of the ipsi- and contralateral sites were computed. Results: Correlations between proximal and distal BMD values within one bone were moderate for both left (R²=0.37) and right humeri (R²=0.40). BMD comparison between left and right humeri revealed high correlations for both the distal (R²=0.90) and the proximal humerus (R²=0.74) (all P<0.01). Elderly specimen (≥70 years) showed better intersite correlations between all regions than younger specimen (<70 years). Conclusion: High correlations between contralateral BMD values may be the result of similar biomechanical loading conditions. Although a relationship between proximal and distal bone quality of the same bone was found, the moderate coefficient suggests that ipsilateral measurements do not provide a good prediction of humeral head BMD. Bone quality at the humeral head is best predicted by BMD measurements at the contralateral location rather than the ipsilateral distal site.