Introduction Ultrasound is a readily available and widely used tool in the investigation of rotator cuff pathology in the shoulder. Reports in the literature as to the diagnostic accuracy of ultrasound in diagnosing cuff tears vary widely. Accuracy rates varying from 50% to 100% have been reported. Most reports reflect the accuracy rates from a single sub-specialized institution.

Method Sity-one consecutive patients with rotator cuff pathology diagnosed on ultrasound, underwent arthroscopy of the shoulder and rotator cuff repair, if a full thickness tear was found at surgery. Most patients had their ultrasound ordered by the referring doctor, prior to my initial review. The ultrasounds were performed at various suburban practices. Most were performed at branch practices of one of the three ‘corporate’ practices in Sydney. All full thickness tears were repaired arthroscopically.

Results Ultrasound correctly identified rotator cuff tears in 80.3%. Four of 61 patients (6.6%) were reported as having partial thickness tears and at surgery were found to have small full-thickness tears. Six of 61 patients (9.8%) had small full thickness tears diagnosed on ultrasound, but were found to have partial thickness tears at surgery. One patient (1.6%) had an ultrasound diagnosis of a tear but had an intact tendon at surgery. One patient (1.6%) was found to have a full thickness tear with an ultrasound that reported an intact tendon.

Conclusions Ultrasound is a valuable tool on the investigation of patients with rotator cuff pathology. It is not reliable in differentiating partial thickness from small full thickness cuff tears. This differentiation is not critical and should not significantly change the patient’s treatment. Reasons for false positive and false negative ultrasounds will be given. Ultrasound for the diagnosis of rotator cuff tendon tears, as performed in suburban practices, is accurate in up to 97% of cases.