Mr Karsenti is from the Nova Southeastern University School of Medicine, Ft Lauderdale, and Dr Bancroft is from the Department of Radiology and Dr Homan is from the Department of Orthopedic Surgery, Florida Hospital, Orlando, Florida.
Mr Karsenti and Drs Bancroft and Homan have no relevant financial relationships to disclose.
Correspondence should be addressed to: Laura W. Bancroft, MD, Department of Radiology, Florida Hospital, 600 E Rollins, Orlando, FL 32803 (firstname.lastname@example.org).
A 19-year-old football player presented with shoulder pain after a football tackling injury.
Figure 1: Radiograph (A) and magnetic resonance arthrographic image (B).
Reverse Humeral Avulsion of the Glehohumeral Ligament
A 19-year-old man sustained a reverse humeral avulsion of the glenohumeral ligament (HAGL) from a football tackling maneuver. Reverse HAGL lesions are the result of posterior capsular detachment and failure of the posterior band of the inferior glenohumeral ligament at the humeral attachment caused by sudden forces on the posterior capsule. Injuries of the inferior glenohumeral ligament are classified with the West Point nomenclature, categorized as either anterior or posterior, and then subclassified as purely ligamentous, associated with bony avulsion fragment, or floating.1
Convulsive disorders, direct traumas, and motor vehicle accidents account for the majority of traumatic causes of posterior shoulder injury with a mechanism of forceful adduction and internal rotation of the upper extremity.2 In addition to reverse HAGL injuries, other lesions caused by posterior shoulder instability include reverse Bankart lesions, reverse Hill-Sachs lesions, superior labral anterior and posterior lesions, and Bennett lesions.2,3
Diagnosis of a reverse HAGL injury is considered difficult because of the various clinical presentations.4 The clinical diagnosis is based on history and physical examination. Symptoms include reproduction of pain, instability, or apprehension when the arm is in the provocative position (ie, adduction, flexion, and internal rotation); positive provocative clinical maneuvers (ie, posterior stress, pivot-shift, jerk, or load and shifting tests); and load-shift and apprehension tests with a translation of humeral head on the glenoid fossa more than 1 cm.4 Pain reflects the innervation of the inferior glenohumeral ligament by redundant branches of the axillary nerve (95%) or, less commonly, the radial nerve (5%).5
Arthrography for the assessment of joint capsule integrity is optimally performed in conjunction with magnetic resonance or computed tomography arthrography if a contraindication exists to magnetic resonance imaging. Conventional arthrography will demonstrate extravasation of contrast from the glenohumeral joint into the posterolateral shoulder soft tissues on the internal rotation view (Figure 2).
Figure 2: Internal rotation view arthrogram showing reverse humeral avulsion of the glenohumeral ligament with extravasation of contrast (arrows) from the glenohumeral joint into the posterolateral shoulder soft tissues.
Magnetic resonance arthrography is widely believed to be the most sensitive non-invasive examination for the evaluation of the labrocapsular complex,6,7 specifically for HAGL.8–11 Hottya et al8 reported that magnetic resonance arthrography findings correlated well with surgical findings of tears involving the posterior stabilizers after posterior shoulder dislocation. Imaging studies were helpful in diagnosing posterior shoulder abnormalities, allowing for proper preoperative planning.8 Chung et al9 described magnetic resonance arthrographic findings in 17 patients with humeral avulsion of the posterior band of the glenohumeral ligament and reported that the lesions could be isolated or found in conjunction with posterior or anteroinferior capsulolabral abnormalities.
In the current patient, axial T1-weighted images without (Figure 3A) and with (Figure 3B) intra-articular contrast demonstrated focal discontinuity of the posterior band of the inferior glenohumeral ligament. Furthermore, the contrast extended posterolateral to the joint capsule through the defect. The axial T1-weighted magnetic resonance arthrographic image showed a focal collection of contrast posterolateral to the disrupted glenohumeral ligament (Figure 3C). The sagittal image delineated the…