| March2006 Case of the Month | |
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Compiled By: Andrew J. Hwang, M.D.
History: 17 year old female who fell on her shoulder while skiing with subsequent pain and limited range of motion.
Exam: MRI of the shoulder, coronal PD SPIR, T1 SE, T2 SE and axial GRE.
Findings: Best demonstrated on the coronal dataset is discontinuity of the inferior glenohumeral ligament at its humeral attachment with capsular hemorrhage extending inferiorly through the defect.
Diagnosis: HAGL lesion
Discussion: The HAGL lesion refers to a tear or avulsion of the inferior glenohumeral ligament from its humeral attachment and results from an anterior shoulder dislocation or subluxation. It typically occurs in patients over the age of 30 and most commonly presents with continued pain and apprehension following an anterior dislocation.
On MRI, the capsular discontinuity at the humeral neck attachment is well demonstrated, and the torn inferior glenohumeral ligament may assume a thickened, wavy or irregular configuration, with increased signal intensity. MR arthrography may demonstrate contrast extravasation through the capsular disruption, below the axillary pouch. Concomitant osseous injuries associated with a recent anterior shoulder dislocation, including a Hill-Sachs injury, are also often noted.
When a HAGL lesion is encountered, careful inspection for specific associated injuries is warranted. Tears of the rotator cuff, especially the subscapularis tendon are not uncommonly associated with the HAGL lesion. Injuries to the biceps tendon and anchor, rotator interval, as well as the posterior glenoid labrum are also occasionally associated with the HAGL lesion. In addition, several variants of the HAGL lesion have been described. These include the AIGHL, or floating HAGL lesion, in which the HAGL occurs in combination with a Bankart lesion, as well as the reverse HAGL, where the posterior band of the inferior glenohumeral ligament is torn as opposed to the anterior band. When a small bone fragment arising from the humeral capsular attachment is identified, a BHAGL, or bony HAGL lesion, is present.
If the defect is small and demonstrates surrounding hemorrhage which would facilitate healing, an initial conservative approach utilizing physical therapy is typically implemented. In the setting of continued instability or if a large defect is present, open or arthroscopic repair is undertaken. The presence of a bony HAGL usually necessitates an open repair with excision of the bony fragment followed by reattachment of the glenohumeral ligaments to their origin on the anterior humerus.
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References:
- Zlatkin, Michael B. MRI of the Shoulder, Lippincott, Williams and Wilkins, Philadelphia, PA 2002.
- Stoller DW, Tirman TJ, Bredella MA. Diagnostic Imaging Orthopaedics. Amirsys Inc. Salt Lake City, UT. 2004.
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