■ sports medicine update Humeral Avulsion of the Glenohumeral Ligament: Injury Pattern and Arthroscopic Repair Techniques

The pathology of shoulder instability includes injury to both labrum and capsule. Labral injury can occur via separation of the labrum from the glenoid rim or direct bony injury to the anteroinferior glenoid (Bankart lesion).1,2 In most cases, capsular injury oc-curs as plastic deformation of the capsule or capsule stretch-ing. However, in a small num-ber of cases, capsular rupture either midsubstance or directly off the humeral attachment may occur.3,4 This type of cap-sular detachment is known as a humeral avulsion of the gle-nohumeral ligaments (HAGL). Bach et al5 fi rst described a HAGL lesion of the lateral cap-sule that was treated with open repair resulting in satisfactory outcomes. Although infre-quently encountered, making the diagnosis of a HAGL le-sion and subsequent treatment are important to obtain a stable shoulder joint. Overall, the incidence of a HAGL lesion in the setting of shoulder instability is a relative-ly uncommon event, but may approach up to 10 % of instabil-ity injury patterns.6 Wolf et al,6 in a review of 64 shoulders with the diagnosis of glenohumeral instability, found a HAGL le-sion in 6 patients (9.3%). Bokor et al7 reviewed 547 shoulders with instability, and the cause of instability was considered to be avulsion of the lateral cap-sule, including the inferior gle-nohumeral ligament from the neck of the humerus, in 41 pa-tients (7.5%). In 6 of 33 patients (18.2%) who underwent revi-sion procedures for instability, a diagnosis of a HAGL lesion was made, highlighting the need for identifi cation and treatment of these lesions at the time of the index procedure. There have been reports of HAGL injuries in combina-tion with a Bankart lesion,8-10 emphasizing the important of a complete evaluation of the shoulder joint even in the pres-ence of labral detachment.11 Although 94 % of HAGL le-sions have been diagnosed after violent trauma,4,12 a case report exists of a HAGL le-sion resulting from repetitive microtrauma associated with overhand throwing.1