Diffuse idiopathic skeletal hyperostosis (DISH) of the shoulder. A controlled radiological study.

The prevalence of hyperostotic spurs (HS) in different areas of the shoulder was studied in 36 probands with and 58 probands without thoracospinal hyperostosis on lateral chest radiographs. Bilateral shoulder radiographs in three projections were analysed blindly, recording the presence of HS at six separate sites (glenoid, greater tuberculum, acromion, acromioclavicular joint, coracoid and humeral shaft) and applying defined grading criteria. The prevalence of HS ranged from 11.7% of the shoulders at the coracoid to 50.0% at the glenoid. The prevalence of HS was similar on both sides [right, 30.1% of the sites versus left, 27.0%, relative risk (RR) 1.12 (95% confidence interval [Cl] 0.93-1.35)] and was not related to sex and history of work. Classification for the presence of shoulder hyperostosis was identical on both sides with the exception of one individual. In probands with thoracospinal and shoulder hyperostosis all areas analysed contributed to the classification. However, this was particularly prominent at the humeral shaft [RR 5.3 (95% Cl 2.1-13.0)] and the coracoid [RR 8.4 (95% Cl 1.9-36.4)]. These results indicated that the prevalence of HS and the specificity for the presence of diffuse idiopathic skeletal hyperostosis (DISH) vary between different sites. We suggest that future grading criteria for shoulder hyperostosis take into account the localization of HS, in addition to their number and size.