Kevin Daniel Lee MD, Presenter: Nothing to Disclose

Hugue Alcide Ouellette MD, Abstract Co-Author: Perseptive clinical trial consultant

Miriam Antoinette Bredella MD, Abstract Co-Author: Nothing to Disclose

Phillip F.J. Tirman MD, Abstract Co-Author: Nothing to Disclose

Cecilia Wang MD, Abstract Co-Author: Nothing to Disclose

Thorsten Wischer MD, Abstract Co-Author: Nothing to Disclose

The purpose of this exhibit is: 1. To review the definition of the anterior labroligamentous periosteal sleeve avulsion(ALPSA)lesion. 2. To discuss the implications of the injury for shoulder stability and the role of MRI prior to arthroscopic evaluation. 3. To review the MR and MR arthrographic imaging findings in ALPSA lesions.

* Definition and pathophysiology of the ALPSA lesion and how it occurs. * Description of the ALPSA lesion at arthroscopy and the role of MRI in guiding the arthroscopist. * Review of imaging findings with both routine MRI and MR arthrography. * Representative cases that demonstrate ALPSA lesions on both routine and arthrographic MR. * Discussion of abduction external rotation (ABER) imaging.

Major teaching points: 1. ALPSA is a Bankart variant that can occur after anterior shoulder dislocation and result in anterior instability. 2. The definitive imaging finding in ALPSA lesions is medial displacement of the anterior-inferior labrum without fluid signal intensity transgressing the scapular periosteum. 3. ABER postioning places tension on the anterior-inferior labrum and may improve detection of ALPSA lesions.

Lee, K, Ouellette, H, Bredella, M, Tirman, P, Wang, C, Wischer, T, The Anterior Labroligamentous Periosteal Sleeve Avulsion Lesion: Findings on MR and MR Arthrographic Imaging.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5009579.html