Lack of uniformity in diagnostic labeling of shoulder pain: time for a different approach.

Diagnostic labels for shoulder pain (e.g., frozen shoulder, impingement syndrome) are widely used in international research and clinical practice. However, about 10 years ago it was shown that the criteria to define those labels were not uniform. Since an ongoing lack of uniformity seriously hampers communication and does not serve patients, we decided to evaluate the uniformity in definitions. Therefore, we compared the selection criteria of different randomised controlled trials (RCTs). This comparison revealed some corresponding criteria, but no uniform definition could be derived for any of the diagnostic labels. Besides the lack of uniformity, the currently used labels have only a fair to moderate interobserver reproducibility and in systematic reviews none of the separate trials using a diagnostic label show a large benefit of treatment. This, altogether, seems sufficient reason to reconsider their use. Therefore, we strongly suggest to abolish the use of these labels and direct future research towards undivided populations with "general" shoulder pain. Possible subgroups with a better prognosis and/or treatment result, based on common characteristics that are easily and validly reproducible, can then be identified within these populations.