Correlation of pathology observed in double contrast arthrotomography and arthroscopy of the shoulder.

Correlation of double contrast arthrotomography (DCAT) of the shoulder and arthroscopic surgery diagnostic results have been undertaken in 55 patients with persistent shoulder pain or involuntary shoulder instability. During the period March 1984 to December 1986, 55 patients underwent DCAT followed by videotaped diagnostic shoulder arthroscopy. The primary indication for DCAT was persistent pain in 36 patients and instability in 17 patients. DCAT was performed according to the method of El-Khoury and Albright, and all arthroscopies were performed in a similar fashion by the senior author (HJS). Both tests were reviewed separately, retrospectively, and their results were correlated. For combined (anterior and posterior) labral pathology, the sensitivity/specificity for the instability group was 0.91/0.91, respectively; sensitivity/specificity for the pain group was 0.63/0.94. DCAT accurately depicted the status of 76% of anterior labrums and 96% of posterior labrums. For complete rotator cuff tears, sensitivity/specificity was 1.0/0.94. The status of a complete rotator cuff tear was accurately depicted in 91% of patients. Partial rotator cuff tears were missed in 83% of patients by DCAT. The presence or absence of loose bodies was accurately represented by 96% of DCAT. Arthroscopy showed that 71% of the instability patients had a labral tear, compared with 44% of the pain patients. Rotator cuff pathology was present in 12% of instability patients and 42% of pain patients. These findings indicate that DCAT may be a conditionally reliable test in the diagnosis of shoulder instability. DCAT must be considered inconclusive, however, in the painful shoulder without instability. Its usefulness as a preoperative screening test is discussed, and a diagnostic algorithm is presented. DCAT does not equal the diagnostic accuracy of shoulder arthroscopy.