抄録
The purpose of this study was to investigate the usefulness of preoperative evaluation by ultrasonography (US) of rotator cuff tears (RCT). 23 shoulders in 23 cases with rotator cuff tears were examined using 7.5-13 MHz linear phased transducer in both the long and short axial plane. The ultrasonic surface contour of the rotator cuff tendon in the long axial plane was classified into convex, flat, concave and defective. We defined the size of RCT measured using US (the US size of RCT) was the product of width of RCT in the long axial plane by that in the short axial plane. We compared the ultrasonic surface contour and the US size of RCT with the arthroscopic findings according to the classifications of Deorio and Cofield. In the arthroscopic findings, there were four bursal-side incomplete tears, 2 articular-side incomplete tears, 8 small tears, 5 medium tears and 4 large tears. It was difficult to predict the arthroscopic findings from the ultrasonic surface contour of the rotator cuff tendon in the long axial plane, especially when the surface was flat or concave. In the US size of RCT, there were significant differences between a large tear (258 ± 70 mm2) and a medium tear (168 ± 33 mm2) or a small tear (102 ± 35 mm2) in the arthroscopic findings (p<0.05). We proposed a new diagnostic criteria that included 2 factors, the ultrasonic surface contour and the US size of RCT. In the criteria, a small rotator cuff tear was diagnosed with less than 150 mm2, a medium tear was more than 150 mm2 and less than 250 mm2 and a large tear was more than 250 mm2 in the US size of RCT. In 22 out of 23 cases in this study, the diagnosis by the criteria corresponded to the arthroscopic findings.
