External versus endoscopic ultrasound: Non-inferiority assessment for visualization of various structures of interest in the shoulder

Certain structures and pathologies can be difficult to reveal under videoscopy alone during arthroscopic surgery. Ultrasound can be a useful contribution in arthroscopic diagnostic and therapeutic procedures. The main aim of the present study was to assess equivalence between endoscopic and external ultrasound for shoulder exploration. Secondary objectives comprised qualitative assessment of endoscopic ultrasound images and comparative assessment of acquisition time between the two techniques.An anatomic non-inferiority study was conducted on 6 shoulders from 3 subjects with a mean age of 84 years. After ultrasound examination by a radiologist specializing in osteoarticular imaging, shoulder arthroscopy was performed by a single specialized surgeon, using an ultrasound endoscope. Number of visualized structures and image quality were assessed by independent observers.Ten of the 11 structures of interest (91%) were visualizable on endoscopic ultrasound, versus 4 (36%) on external ultrasound (p0.05). Mean endoscopic acquisition time was 9.5±6.3minutes [range, 5;22]. In the 11 structures, image quality was better on endoscopic than external ultrasound, except for the acromioclavicular joint, where quality was better on external ultrasound, and the lateral side of the rotator cuff, where quality was equivalent.The present study demonstrated equivalence between endoscopic and external ultrasound for shoulder exploration.IV, Non-inferiority cadaver study.