Ueli Studler, Presenter: Nothing to Disclose

Christian W.A. Pfirrmann MD, Abstract Co-Author: Nothing to Disclose

Juerg Hodler MD, Abstract Co-Author: Research Consultant, Smith & Nephew plc Research Consultant, Bayer AG

Bernhard Jost, Abstract Co-Author: Nothing to Disclose

Marco Zanetti MD, Abstract Co-Author: Nothing to Disclose

To assess the association between bony abnormalities of the lesser tuberosity and subscapularis tendon lesions

Standard radiographs and shoulder MR arthrography in 70 patients (31 with normal subscapularis tendons, 39 with subscapularis tendon lesions) with arthroscopic confirmation were independently analyzed by two radiologists. Cortical irregularities and cyst formation of the humeral lesser tuberosity were reviewed on radiographs and MR images. The imaging findings were compared with arthroscopic observations regarding subscapularis tendon lesions and with fatty atrophy of the subscapularis muscle on MR images.

For subscapularis tendon lesions, the sensitivity of cortical irregularities and cysts on radiographs was 44%/51% (reader 1/reader 2) and 21%/21%; the specificity was 65%/68% and 87%/87%. The sensitivity of cortical irregularities and cysts on MR imaging was 64%/72% and 36%/39%; the specificity was 72%/48% and 81%/77%. For fatty atrophy of the subscapularis muscle, the sensitivity of cortical irregularities and cysts on radiographs was 67%/73% and 17%/27%; the specificity was 63%/63% and 83%/85%. The sensitivity of cortical irregularities and cysts on MR imaging was 67%/82% and 17%/55%; the specificity was 42%/39% and 70%/73%.

Cysts seen in the lesser tuberosity on shoulder radiographs or MR arthrography are moderately specific for subscapularis tendon lesions and muscle atrophy. However, sensitivity of such abnormalities in the lesser tuberosity remains rather low for subscapularis lesions.

The presence of cystic abnormalities of the lesser tuberosity seen on shoulder radiographs should focus the attention of the reader on subscapularis lesions.

Studler, U, Pfirrmann, C, Hodler, J, Jost, B, Zanetti, M, Bony Abnormalities of the Lesser Tuberosity on Standard Radiographs and MR Images: Comparison of Findings with Subscapularis Tendon Lesions at Arthroscopy.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5011153.html