- Email: [email protected]
Humeral avulsion of glenohumeral ligaments as a cause of anterior shoulder instability
Humeral Avulsion of Glenohumeral Ligaments as a Cause of Anterior Shoulder Instability Eugene M. Wolf, M.D., Joseph C. Cheng, M.D., and Kyle Dickson, M.D.
Summary: The avulsion of the glenohumeral ligament labral complex at the glenoid (Bankart lesion), as well as ligamentous laxity are well known causes of anterior shoulder instability. A lesser known entity, the humeral avulsion of glenohumeral ligaments (HAGL), was studied to determine its incidence and its role in anterior glenohumeral instability. Sixty-four shoulders with the diagnosis of anterior instability were prospectively evaluated by arthroscopy for intraarticular pathology, including Bankart, capsular laxity, and HAGL lesions. Six shoulders were found to have HAGL lesions (9.3%) 11 shoulders with generalized capsular laxity (17.2%), and 47 shoulders with Bankart lesions (73.5%). In patients with documented anterior instability without a demonstratable “primary” Bankart lesion, a HAGL lesion should be ruled out. This lesion is readily recognized arthroscopically, and an appropriate repair of this lesion can restore anterior stability to the patient. The pathological anatomy of the HAGL lesion and our treatment of this lesion is discussed. Key Words: HAGL lesion-Shoulder instabilityArthroscopic evaluation and repair.
R
ecurrent anterior glenohumeral instability is a common clinical problem that can lead to significant disability. The pathology of anterior glenohumeral instability has been studied extensively by many authors.‘-lg Pathologies involving avulsion of the ligament labral complex at the glenoid (Bankart lesion), intraligamentous lesions, or laxity of glenohumeral ligaments, can all lead to instability of the shoulder.1-17 Proper identification and treatment of the pathology responsible for recurrent anterior shoulder instability is essential and ensure return of the shoulder to normal function. Although the vast majority of the literature emphasizes the importance of the avulsion of the glenohumeral ligament labral complex from the glenoid as the
From the California Orthopaedic and Sports Medicine Group, and the Department of Orthopedic Surgery, University of California, San Francisco, California, U.S.A. Address correspondence and reprint requests to Eugene M. Wolf; M.D., California Orthopaedic and Sports Medicine Group, 3400 California St, San Francisco, CA 94118, U.S.A. 0 I995 by the Arthroscopy Association of North America 0749.8063/95/1105-1144$3.00/O
600
Arthroscopy:
The
Journal
of Arthroscopic
and
Related
essential pathology in traumatic anterior dislocation of the shoulder,’ there is evidence that the avulsion can occur at the humeral attachments.17-I9 In cadaver studies, Bigliani et al.17 showed that a bone-ligament-bone specimen failed under tension at the glenoid in 40%, in-substance in 35%, and at the humerus insertion in 25% of the specimens. In 1942, Nicola” first described the avulsion of the capsule from the neck of the humerus in four out of five acute dislocations that were surgically explored. This avulsion of the glenohumeral ligament from the humerus as opposed to the glenoid rim (Bankart lesion) was largely ignored in the literature for over 40 years until two similar cases, lateral capsular avulsions from the humerus were described by Bach et al. in 1989.19 The recognition of these lesions was fortuitous and aided largely because the capsular ligaments had avulsed bony fragments from the humerii. The difficult dissection of the subscapularis from the normally conjoined capsule explains the relative absence of the humeral avulsion of glenohumeral ligaments (HAGL) lesion from the literature. The purpose of this study is to present the incidence and treatment of HAGL lesions in anterior glenohuSurgery,
Vol
11, No
5 (October),
1995:
pp
600-607
601
HAGL LESION meral instability. We consecutively analyzed 64 shoulders with anterior instability and documented 6 cases of HAGL. We confirmed that the HAGL lesion represents another cause of anterior shoulder instability. The pathoanatomy and treatment of these cases are described.
MATERIALS
AND METHODS
This is a prospective study of 82 consecutive shoulders with instability that had failed conservative therapy and required arthroscopic surgical intervention for diagnosis or treatment. The study period dated from November 1989 to March 1992. All patients had a preoperative examination under anesthesia to assess shoulder instability. We believe this examination is critical and is best performed in the lateral decubitus position with the shoulder abducted and externally rotated. A compressive force was then applied on the glenoid in an attempt to displace the humeral head either anteriorly or posteriorly. This has been an invaluable tool for excluding multidirectional and posterior instability of the shoulder prior to arthroscopy.20 Eighteen patients with posterior instability and multidirectional instability were excluded from this study. The remaining 64 shoulders with pure anterior instability on examination under anesthesia were prospectively evaluated by diagnostic arthroscopy as described by the senior author.22 Of the 64 shoulders with anterior instability in 64 patients, the epidemiology is as follows. The age of presentation ranges between 12 and 46 years old with an average of 28 years. This study includes 50 male and 14 female patients. The duration of preoperative instability was from 6 days to 28 years with an average of 2 years 10 months. All intraarticular pathology was documented.
RESULTS Out of the 64 shoulders, there were 47 Bankart lesions (73.5%) 11 capsular laxity lesions (17.2%), and
TABLE
6 HAGL lesions (9.3%). The six shoulders with HAGL lesions all had surgical procedures performed as described in the following case studies. The patients with HAGL lesions all had one single traumatic episode as the inciting event of their anterior instability. All patients were treated conseravatively ranging from 1 month to 22 years, and all had a history of multiple recurrences (Table 1). One patient had a prior open Bankart procedure that failed, two patients had associated Hill-Sachs lesions. Patients were followed for an average time of 40 months (26 to 54 months). All patients reported no disability and none had a recurrence at the time of their last clinic visit or telephone interview.
Case 1 A 40-year-old right-hand dominant man with history of recurrent right anterior shoulder dislocations since age 18, presented with a l-year history of increasing frequency and ease of the anterior dislocations. Physical examination was remarkable for external rotation of 30” at 90” of abduction causing pain and apprehension. There was no evidence of effusion, muscular atrophy, ligamentous laxity, tenderness, neurologic involvement, or impingement. Examination of the opposite shoulder was unremarkable. The radiographs showed a classical Hill-Sachs lesion. Examination under anesthesia showed anterior-inferior instability. Arthroscopic examination of the right shoulder showed glenohumeral ligament labral complex intact on the glenoid rim. When the humeral side of the inferior glenohumeral ligament (IGL) was inspected, the ligament capsule complex was avulsed and the subscapularis tendon was visualized through the defect. An open repair by the standard deltopectoral approach was performed. After division of the subscapularis tendon 1 cm from the lesser tuberosity, a separate and distinct lateral capsular edge was viewed avulsed off the anterior inferior aspect of the anatomic humeral neck (Fig 1). The lateral avulsed border was smooth, rounded, and retracted into the joint. However, the
1. Patient PI-ojile
Pt.
Age (Y)
Sex
Side
Mechanism
Duration
1 2 3 4 5 6
40 12 20 16 24 30
M F M M F M
Right Right Right Left Left Left
Basketball Diving Diving Football Fall Basketball
22 Y 18 mo 13 mo lm 5 mo 5Y
Associated
Lesion
Prior
Rx
Hill-Sachs
Hill-Sachs Bankart
repair
Follow-up 54 52 45 36 26 26
(mo)
E. 44. WOLF ET AL.
602
Subscapularis Coracohumeral
tendon ligament lenohumeral
ligament
don stump and tied directly on top. The subscapularis was repaired and the wound closed in the usual fashion. The patient is now 4 years 6 months after the surgical repair and reports no pain or instability and has a full range of motion. Case 2
Anterior
view
FIG 1.
Schematic drawing of HAGL lesion in Case 1. After the division of subscapularis tendon 1 cm from its insertion to the humerus, the middle and inferior glenohumeral ligament is seen avulsed off its humeral insertion site.
lesion was still mobile enough to be repositioned to the normal insertion site. The lesion was repaired by creating a bleeding trough of bone along the anatomic neck with an arthroscopic burr. No. 1 nonabsorbable sutures were used to pull the capsule into the trough medial to the subscapularis tendon attachment. The sutures were brought out through the subscapularis ten-
A 12-year-old right-hand dominant boy first injured his right shoulder in a diving accident 18 months before presentation. Since that time, he had sustained eight more episodes of dislocations. Physical examination at presentation was notable for tenderness over the anterior aspect of the glenohumeral joint. The apprehension test was positive with decreased external rotation. No evidence of effusion, muscle atrophy, neurologic involvement, or impingement existed. A magnetic resonance image (MRI) (Fig 2) was read as “suggestive of an anterior labral lesion.” Retrospectively, this clearly showed the capsular avulsion from the humerus. Examination under anesthesia again showed pure anterior instability. Arthroscopic evaluation showed an intact ligament labral complex on the glenoid side. Exploring the humeral insertion of the IGL revealed muscle fibers of the subscapularis muscle. A probe was inserted and located the lateral avulsed edge of the anterior band of the IGL inferior to the subscapularis tendon and in the axillary pouch. A standard open approach to the shoulder and repair was performed
FIG 2.
Preoperative transaxial MRI of the shoulder in Case 2. The short arrow points to the avulsed lateral edge of the glenohumeral ligament. The long arrow shows that the glenohumeral ligament remains intact on the glenoid rim and appears somewhat redundant as the capsule has retracted medially.
HAGL
LESION
603
Anterior
Pectoralis
major Coracoid
Tendon
r
A
HAGL
m.
/
of biceps
/-
Posterior
FIG 3.
(A) Axial view of a HAGL lesion. The tom lateral edge of the glenohumeral ligament is seen. (B) Magnified view of arthroscopic repair of a HAGL lesion. The sutures are pulled anteriorly through the anterior lateral portal that traversed the subscapularis muscle. Half the sutures are then separated and passed bluntly through the substance of the deltoid by a clamp and the other sutures are passed through the subcutaneous tissue. These are then tied onto each other, pulling the avulsed edge of the capsule back to its humeral insertion site.
similar to the previous case. The patient is now 4 years 4 months postoperative without any symptoms of instability and full range of motion. Case 3 A 20-year-old right-hand dominant man initially injured his right shoulder after diving from a cliff 13 months before presentation. The patient continued to have recurrent dislocations despite conservative treatment. Physical examination was remarkable for external rotation beyond 0” at 90” of abduction causing discomfort and apprehension. Arthroscopic examination showed a normal labrum with an avulsion of the glenohumeral ligament from the humerus exposing the underlying subscapularis. The edge of the capsule was freshened with a full radius resector, and the burr was used to freshen the insertion site. Four No. zero polydioxanone sutures were placed with a suture hook through the avulsed edge of the capsule through the standard anterior inferior portal.” An additional anterior lateral portal was created 2-cm lateral and 2-cm inferior to the coracoid.
This portal traversed the subscapularis insertion site on the humerus. All four sutures were pulled out through this anterior lateral portal, reapproximating the lateral capsule to its humeral insertion site. Half of the sutures were then separated and passed subfascially below the deltopectoral fascia and half the sutures were passed subcutaneously below the skin (Fig 3). The sutures were tied over the deltopectoral fascia. The patient is 3 years 9 months postoperative without any symptoms of instability or discomfort. The patient returned to all prior physical activity and is currently playing competitive tennis. Case 4 A 16-year-old right-hand dominant boy dislocated his left shoulder at football practice 1 week before
E. M. WOLF ET AL.
604 Superior glenohumeral
ligament
Middle glenohumeral
ligament
Inferior glenohumeral
bile accident 5 months before presentation. She was seen at the time of her second dislocation after a minor fall. Despite conservative treatment with resistive exercises, she continued to have apprehension and pain on abduction and external rotation of her left shoulder. Examination under anesthesia showed gross instability in the anterior-inferior plane. Arthroscopic examination showed the glenohumeral ligament to be normally attached onto the glenoid labrum. There was a large Hill-Sachs lesion noted. When the humeral side was inspected, the entire anterior half of the IGLC including its anterior band was avulsed. This defect was repaired arthroscopically similarly to the repair described above. The patient is 2 years 2 month postoperative, reports no instability, and is able to return to her prior activity level.
Posterior view Case 6 FIG 4. A typical HAGL lesion as viewed posteriorly. defect in the inferior lateral capsule as the glenohumeral avulsed off its humeral insertion site.
There is a ligaments
presentation, The patient was immobilized for 3 weeks. Because of persistent symptoms of instability and the desire to return to football as soon as possible, the patient and his parents opted for surgical fixation 1 month after the initial dislocation. The examination under anesthesia revealed anterior subluxation without any inferior component. Arthroscopy showed a small longitudinal split along the labrum and slight separation from the anterior glenoid. One easily could have mistaken the split in the labrum as the primary pathology but, with further probing, there was no significant displacement. When the humeral side was inspected, a large HAGL lesion was seen. The HAGL lesion extended from the most axillary portion of the anterior half of the IGLC on the humeral head to just inferior to the superior border of the subscapularis tendon (Fig 4). The HAGL lesion was arthroscopically repaired by burring the bed of insertion posterior to the subscapularis, placing five PDS sutures, and pulling the capsule into the old insertion site. The remainder of repair was similar to Case 3. The 36-month follow-up showed the patient without any symptoms of instability and with no difference in strength testing between his two shoulders. He returned to football as a running back. Case 5
The patient is 24-year-old right-handed woman who initially dislocated her left shoulder during an automo-
The patient is a 30-year-old right-handed man who initially dislocated his left shoulder while going for a lay up playing basketball, with the arm abducted and externally rotated. He had subsequently dislocated his left shoulder multiple times requiring an open Bankart procedure. The patient did well for 5 years when he again dislocated his left shoulder playing basketball. On physical examination, he was found to have a positive apprehension sign and lacked approximately 45” of external rotation with the shoulder abducted at 90”. Examination under anesthesia found the patient to have gross instability anteriorly. Arthroscopically, there was capsular redundancy along the glenoid labmm from the prior Bankart repair. There was a large defect in the anterior inferior capsule on the humeral side. This was felt to be the lesion responsible for anterior instability. The defect was repaired arthroscopically as described above. The patient is currently 2 years 2 months postoperative. He denies any pain or loss of motion, and plays basketball regularly.
DISCUSSION The glenohumeral ligaments insert on the glenoid via the labrum, and the adjacent periosteum.1”6 Numerous studies have documented the functional significance of the glenohumeral ligament labral complex (GLLC) in maintaining stability of the shoulder throughout range of motion.11X’6 The subscapularis muscle acts as the principle dynamic anterior stabilizer when the arm is at 0” of abduction. The inferior GLLC (IGLLC) becomes the primary anterior shoulder stabi-
HAGL LESION lizer when the arm is externally rotated and abducted to 90”.16 The gross and histologic anatomy of the IGL has been well described.” The ligament is divided into an anterior, posterior band and the intervening axillary pouch with attachment to the articular edge of the humeral head in a collar-like or ‘ ‘V” shape. l1 The anterior band attaches to the glenoid via the labrum. The avulsion of this GLLC from the glenoid (Bankart lesion) has been established as the primary lesion for anterior inferior instability both clinically and in cadaver stUdies.2,3.8,10.16,23
605
had Hill-Sachs lesions and none had associated rotator cuff disease. Arthroscopic findings were consistent with varying disruptions of the glenohumeral ligaments from the humeral site, rendering the shoulder unstable anteriorly. One patient (Case 6) had had a prior open Bankart procedure. In this patient, the inferior glenohumeral ligament was found to be redundant and well attached to the glenoid rim at time of reoperation, but the humerus can easily sublux anteriorly through the defect at the humeral site. All 6 patients underwent surgical reattachment of their glenohumeral ligament to its humeral insertion site, 2 via open proceRowe et al.*-” reported a 85% incidence of Bankart dures and 4 via arthroscopic procedures. Patients were lesion in patients operated on for traumatic recurrent followed for an average time of 40 months (26 to 52 anterior dislocations, 84% incidence in patients with months). All patients reported no disability and none previous failed anterior stabilizing surgical procedures, had a recurrence at the time of their last clinic visit or and 64% in patients with recurrent anterior shoulder telephone interview. subluxations. The reported percentage of Bankart leIn our study, the 6 shoulders with humeral avulsion sions thought to be responsible for anterior shoulder of the glenohumeral ligament represented a significant instability has varied between 45% and 100%.‘~4~5~12~‘4 portion (35%, 6 of 17) of the group of shoulders (capProcedures designed to obliterate this lesion surgically sular laxity and humeral avulsion) that were unstable have produced excellent results, and confirm its imporand without pathology at the glenoid rim. In the past, tance in anterior instability of the shoulder,8 but not the cause of instability in this group has been postuall cases of recurrent anterior shoulder instability have lated to be capsular laxity, yet there is no accurate, Bankart lesions. Rowe et a1.8found that 15% of recurreliable method to test laxity.8’10 Further proof that a rent dislocations had capsular laxity only, without a HAGL lesion may be responsible for instability was labral avulsion from the glenoid rim. In those cases, seen in Bigliani’s biomechanical study.17 The tensile capsular plication was used to treat these lesions.* property of the IGLC bone-ligament-bone complex Although the Bankart lesion is most often found to was tested to mechanical failure. Three failure sites be responsible for anterior shoulder instability, there were seen: the ligament intrasubstance 35% of the is evidence to suggest that the glenohumeral ligament time; the humeral insertion site 25% of the time; and the glenoid 40% of the time. We believe that this 25% can fail at the humeral insertion site. Nicola” first reported four out of five acute cases of dislocation and reported incidence of HAGL lesion in vitro, as well 6 out of 25 recurrent dislocations where a humeral as our findings, are supportive of the need to carefully avulsion of the capsule occurred. His clinical observaexplore every shoulder arthroscopically for this lesion, tion was confirmed by a subsequent cadaver study especially in those cases where anterior shoulder instawhere he dislocated 50 cadaver shoulders.18 He found bility exists without a frank Bankart lesion. Indeed, that the capsule tore off the humerus with hyperabducclinical study of arthrograms in shoulder dislocations tion (105”) and external rotation, whereas a Bankart have supported two distinct types of lesions: “capsular lesion occurred when hyperabduction was associated rupture” versus “capsular detachment from the glenoid “.‘I This capsular rupture pattern has been estiwith impaction. In our study of 64 shoulders with anterior instability, mated to be 10% in recurrent shoulder dislocations8~2’-23 we found 6 shoulders with HAGL lesions, 47 with and could actually represent the HAGL lesion. Bankart lesions, and 11 with capsular laxity. Analysis We feel the HAGL lesion was the pathology responof our 6 patients with HAGL lesions showed that they sible for anterior instability in our 6 patients, as proper all had one single traumatic episode as the inciting recognition and treatment of HAGL lesions has reevent in the cause of their anterior instability. We canstored glenohumeral stability to all 6 patients. Alnot confirm Nicola’s hypothesis that hyperabduction though this lesion is best identified via diagnostic arthroscopy, studies of acute dislocations with arthrosand external rotation cause glenohumeral ligament failcopy did not note any HAGL lesions, but these studies ure from the humeral side. Initially all patients were were performed without awareness of their potential treated nonoperatively from 1 month to 22 years, and all had multiple recurrences of instability. Two patients presence.*‘**l
606
E. M. WOLF ET AL.
FIG 5. Arthroscopic photograph of a HAGL lesion viewed from the posterior portal. The probe is retracting the avulsed lateral capsule, exposing the underlying subscapularis muscle.
The diagnosis of HAGL lesion as a cause for anterior shoulder instability can be difficult because of the open anterior approach to the unstable shoulder. In attempting to define the plane between the subscapularis tendon and the capsule, the inadvertent entry into the shoulder joint may disguise an actual HAGL lesion. Furthermore, leaving the deeper portion of the subscapularis over the capsule may mask a HAGL lesion. Even with shoulder arthroscopy, this lesion can be overlooked if not specifically searched for in the appropriate area. The arthroscopic finding of an exposed subscapularis muscle (Fig 5) should alert the surgeon to the possibility that a HAGL lesion exists and can potentially cause shoulder instability.
CONCLUSION Disruption of the IGL at the glenoid, humerus, or mid substance will allow the shoulder to dislocate. 2~13~17-19,23 In patients with anterior shoulder instability, without a demonstrable Bankart lesion, the HAGL lesion should be suspected and a well-directed diagnostic arthroscopy performed. The proper recognition and repair of this lesion can restore shoulder stability to the patient.
REFERENCES 1. Adams JC. Recurrent Surg Br 1948;30:26-38.
dislocation
of the shoulder.
J Bone Joint
2. Bankart ASB. Recurrent or habitual dislocation of the shoulder joint. BMJ 1923;2:1132-1133. 3. Bankart ASB. The pathology and treatment of recurrent dislocation of the shoulder joint. Br J Surg 1938;26:23-29. 4. Brav EA. Evaluation of the Putti-Platt reconstruction procedure for recurrent dislocation of the shoulder. J Bone Joint Surg Am 1955;37:731-741. 5. DuToit GT, Roux D. Recurrent dislocation of the shoulder. Twenty-four year study of the Johannesburg stapling operation. .I Bone Joint Surg Am 1956;33:1-12. 6. Glousman R, Jobe F, Tibone .I, Moynes D, Antonelli D, Perry J. Dynamic electromyographic analysis of the throwing shoulder with glenohumeral instability. J Bone Joint Surg Am 1988;70: 220-226. 7. Rowe CR, Sakellarides HT. Factors related to recurrences of anterior dislocations of the shoulder. Clin Orthop 1966;20:4047. 8. Rowe CR, Pate1 D, Southmayd WW. The Bankart procedure: A long-term end result. J Bone Joint Surg Am 1978; 60: 1-16. 9. Rowe CR, Zarins B. Recurrent transient subluxation of the shoulder. J Bone Joint Surg Am 1981;63:863-874. 10. Rowe CR, Zarins B, Ciullo JV. Recurrent anterior dislocation of the shoulder after surgical repair. J Bone Joint Surg Am 1984;66:159-168. 11. O’Brien SJ, Neves MC, Amoczky SP, et al. The anatomy and histology of the inferior glenohumeral ligament complex of the shoulder. Am J Sports iVied 1990; 18:449-456. 12. Palmer I, Widen A. The bone block method for recurrent dislocation of the shoulder joint. J Bone Joint Surg Br 1948;30:5358. 13. Thomas SC, Matsen FA, III. An approach to the repair of avulsion of the glenohumeral ligaments in the management of traumatic anterior glenohumeral instability. J Bone and Joint Surg Am 1989;71:506-513. 14. Watson-Jones R. Note on recurrent dislocation of the shoulder joint. Superior approach causing the only failure in fifty-two operations for repair of the labrum and capsule. J Bone Joint Surg Br 1948; 30:49-52.
HAGL LESION 15. Weber BG, Simpson LA, Hardegger F. Rotation humeral osteotomy for recurrent anterior dislocation of the shoulder associated with a large Hill-Sachs lesion. J Bone J&n Surg Am 1984; 66: 1443-1450. 16. Turkel SJ, Panio MW, Marshall J, Girgis FG. Stabilizing mechanisms preventing anterior dislocation of the glenohumeral joint. J Bone and J&r Surg Am 1981;63:1208-1217. 17. Bialiani LU. Pollock RG. Soslowskv LJ. Flatow EL. Pawluk RJ: Mow VC. Tensile properties of ‘the inferior glenohumeral ligament. / Orthop Res 1992; 10:187-197. 18. Nicola T. Anterior dislocation of the shoulder: The role of the articular capsule. J Bone Joint Surg Am 1942;25:614-616.
607
19. Bach BR, Warren RF, Fronek J. Disruption of the lateral capsule of the shoulder. J Bone JoointSurg Br 1988;70:274-276. 20. Wolf EM, Wilk RM, Richmond JC. Arthroscopic bankart repair using suture anchors. Oper Tech Orthop 1991; 1:184-191. 21. Reeves B. Arthrography of the shoulder. J Bone Joint Surg Br 1966;48:424-435. 22. Nixon JR, Young WS. Arthrography of the shoulder in anterior dislocation: A study of african and asian patients. Injury 1977;9:287-293. 23. Kuriyama S, Fujimaki E. Katagiri T, Uemura S. Anterior dislocation of the shoulder joint sustained through skiing: Arthrographic findings and prognosis. Am J Sports Med 1984; 12:339-346.
Summary: The avulsion of the glenohumeral ligament labral complex at the glenoid (Bankart lesion), as well as ligamentous laxity are well known causes of anterior shoulder instability. A lesser known entity, the humeral avulsion of glenohumeral ligaments (HAGL), was studied to determine its incidence and its role in anterior glenohumeral instability. Sixty-four shoulders with the diagnosis of anterior instability were prospectively evaluated by arthroscopy for intraarticular pathology, including Bankart, capsular laxity, and HAGL lesions. Six shoulders were found to have HAGL lesions (9.3%) 11 shoulders with generalized capsular laxity (17.2%), and 47 shoulders with Bankart lesions (73.5%). In patients with documented anterior instability without a demonstratable “primary” Bankart lesion, a HAGL lesion should be ruled out. This lesion is readily recognized arthroscopically, and an appropriate repair of this lesion can restore anterior stability to the patient. The pathological anatomy of the HAGL lesion and our treatment of this lesion is discussed. Key Words: HAGL lesion-Shoulder instabilityArthroscopic evaluation and repair.
R
ecurrent anterior glenohumeral instability is a common clinical problem that can lead to significant disability. The pathology of anterior glenohumeral instability has been studied extensively by many authors.‘-lg Pathologies involving avulsion of the ligament labral complex at the glenoid (Bankart lesion), intraligamentous lesions, or laxity of glenohumeral ligaments, can all lead to instability of the shoulder.1-17 Proper identification and treatment of the pathology responsible for recurrent anterior shoulder instability is essential and ensure return of the shoulder to normal function. Although the vast majority of the literature emphasizes the importance of the avulsion of the glenohumeral ligament labral complex from the glenoid as the
From the California Orthopaedic and Sports Medicine Group, and the Department of Orthopedic Surgery, University of California, San Francisco, California, U.S.A. Address correspondence and reprint requests to Eugene M. Wolf; M.D., California Orthopaedic and Sports Medicine Group, 3400 California St, San Francisco, CA 94118, U.S.A. 0 I995 by the Arthroscopy Association of North America 0749.8063/95/1105-1144$3.00/O
600
Arthroscopy:
The
Journal
of Arthroscopic
and
Related
essential pathology in traumatic anterior dislocation of the shoulder,’ there is evidence that the avulsion can occur at the humeral attachments.17-I9 In cadaver studies, Bigliani et al.17 showed that a bone-ligament-bone specimen failed under tension at the glenoid in 40%, in-substance in 35%, and at the humerus insertion in 25% of the specimens. In 1942, Nicola” first described the avulsion of the capsule from the neck of the humerus in four out of five acute dislocations that were surgically explored. This avulsion of the glenohumeral ligament from the humerus as opposed to the glenoid rim (Bankart lesion) was largely ignored in the literature for over 40 years until two similar cases, lateral capsular avulsions from the humerus were described by Bach et al. in 1989.19 The recognition of these lesions was fortuitous and aided largely because the capsular ligaments had avulsed bony fragments from the humerii. The difficult dissection of the subscapularis from the normally conjoined capsule explains the relative absence of the humeral avulsion of glenohumeral ligaments (HAGL) lesion from the literature. The purpose of this study is to present the incidence and treatment of HAGL lesions in anterior glenohuSurgery,
Vol
11, No
5 (October),
1995:
pp
600-607
601
HAGL LESION meral instability. We consecutively analyzed 64 shoulders with anterior instability and documented 6 cases of HAGL. We confirmed that the HAGL lesion represents another cause of anterior shoulder instability. The pathoanatomy and treatment of these cases are described.
MATERIALS
AND METHODS
This is a prospective study of 82 consecutive shoulders with instability that had failed conservative therapy and required arthroscopic surgical intervention for diagnosis or treatment. The study period dated from November 1989 to March 1992. All patients had a preoperative examination under anesthesia to assess shoulder instability. We believe this examination is critical and is best performed in the lateral decubitus position with the shoulder abducted and externally rotated. A compressive force was then applied on the glenoid in an attempt to displace the humeral head either anteriorly or posteriorly. This has been an invaluable tool for excluding multidirectional and posterior instability of the shoulder prior to arthroscopy.20 Eighteen patients with posterior instability and multidirectional instability were excluded from this study. The remaining 64 shoulders with pure anterior instability on examination under anesthesia were prospectively evaluated by diagnostic arthroscopy as described by the senior author.22 Of the 64 shoulders with anterior instability in 64 patients, the epidemiology is as follows. The age of presentation ranges between 12 and 46 years old with an average of 28 years. This study includes 50 male and 14 female patients. The duration of preoperative instability was from 6 days to 28 years with an average of 2 years 10 months. All intraarticular pathology was documented.
RESULTS Out of the 64 shoulders, there were 47 Bankart lesions (73.5%) 11 capsular laxity lesions (17.2%), and
TABLE
6 HAGL lesions (9.3%). The six shoulders with HAGL lesions all had surgical procedures performed as described in the following case studies. The patients with HAGL lesions all had one single traumatic episode as the inciting event of their anterior instability. All patients were treated conseravatively ranging from 1 month to 22 years, and all had a history of multiple recurrences (Table 1). One patient had a prior open Bankart procedure that failed, two patients had associated Hill-Sachs lesions. Patients were followed for an average time of 40 months (26 to 54 months). All patients reported no disability and none had a recurrence at the time of their last clinic visit or telephone interview.
Case 1 A 40-year-old right-hand dominant man with history of recurrent right anterior shoulder dislocations since age 18, presented with a l-year history of increasing frequency and ease of the anterior dislocations. Physical examination was remarkable for external rotation of 30” at 90” of abduction causing pain and apprehension. There was no evidence of effusion, muscular atrophy, ligamentous laxity, tenderness, neurologic involvement, or impingement. Examination of the opposite shoulder was unremarkable. The radiographs showed a classical Hill-Sachs lesion. Examination under anesthesia showed anterior-inferior instability. Arthroscopic examination of the right shoulder showed glenohumeral ligament labral complex intact on the glenoid rim. When the humeral side of the inferior glenohumeral ligament (IGL) was inspected, the ligament capsule complex was avulsed and the subscapularis tendon was visualized through the defect. An open repair by the standard deltopectoral approach was performed. After division of the subscapularis tendon 1 cm from the lesser tuberosity, a separate and distinct lateral capsular edge was viewed avulsed off the anterior inferior aspect of the anatomic humeral neck (Fig 1). The lateral avulsed border was smooth, rounded, and retracted into the joint. However, the
1. Patient PI-ojile
Pt.
Age (Y)
Sex
Side
Mechanism
Duration
1 2 3 4 5 6
40 12 20 16 24 30
M F M M F M
Right Right Right Left Left Left
Basketball Diving Diving Football Fall Basketball
22 Y 18 mo 13 mo lm 5 mo 5Y
Associated
Lesion
Prior
Rx
Hill-Sachs
Hill-Sachs Bankart
repair
Follow-up 54 52 45 36 26 26
(mo)
E. 44. WOLF ET AL.
602
Subscapularis Coracohumeral
tendon ligament lenohumeral
ligament
don stump and tied directly on top. The subscapularis was repaired and the wound closed in the usual fashion. The patient is now 4 years 6 months after the surgical repair and reports no pain or instability and has a full range of motion. Case 2
Anterior
view
FIG 1.
Schematic drawing of HAGL lesion in Case 1. After the division of subscapularis tendon 1 cm from its insertion to the humerus, the middle and inferior glenohumeral ligament is seen avulsed off its humeral insertion site.
lesion was still mobile enough to be repositioned to the normal insertion site. The lesion was repaired by creating a bleeding trough of bone along the anatomic neck with an arthroscopic burr. No. 1 nonabsorbable sutures were used to pull the capsule into the trough medial to the subscapularis tendon attachment. The sutures were brought out through the subscapularis ten-
A 12-year-old right-hand dominant boy first injured his right shoulder in a diving accident 18 months before presentation. Since that time, he had sustained eight more episodes of dislocations. Physical examination at presentation was notable for tenderness over the anterior aspect of the glenohumeral joint. The apprehension test was positive with decreased external rotation. No evidence of effusion, muscle atrophy, neurologic involvement, or impingement existed. A magnetic resonance image (MRI) (Fig 2) was read as “suggestive of an anterior labral lesion.” Retrospectively, this clearly showed the capsular avulsion from the humerus. Examination under anesthesia again showed pure anterior instability. Arthroscopic evaluation showed an intact ligament labral complex on the glenoid side. Exploring the humeral insertion of the IGL revealed muscle fibers of the subscapularis muscle. A probe was inserted and located the lateral avulsed edge of the anterior band of the IGL inferior to the subscapularis tendon and in the axillary pouch. A standard open approach to the shoulder and repair was performed
FIG 2.
Preoperative transaxial MRI of the shoulder in Case 2. The short arrow points to the avulsed lateral edge of the glenohumeral ligament. The long arrow shows that the glenohumeral ligament remains intact on the glenoid rim and appears somewhat redundant as the capsule has retracted medially.
HAGL
LESION
603
Anterior
Pectoralis
major Coracoid
Tendon
r
A
HAGL
m.
/
of biceps
/-
Posterior
FIG 3.
(A) Axial view of a HAGL lesion. The tom lateral edge of the glenohumeral ligament is seen. (B) Magnified view of arthroscopic repair of a HAGL lesion. The sutures are pulled anteriorly through the anterior lateral portal that traversed the subscapularis muscle. Half the sutures are then separated and passed bluntly through the substance of the deltoid by a clamp and the other sutures are passed through the subcutaneous tissue. These are then tied onto each other, pulling the avulsed edge of the capsule back to its humeral insertion site.
similar to the previous case. The patient is now 4 years 4 months postoperative without any symptoms of instability and full range of motion. Case 3 A 20-year-old right-hand dominant man initially injured his right shoulder after diving from a cliff 13 months before presentation. The patient continued to have recurrent dislocations despite conservative treatment. Physical examination was remarkable for external rotation beyond 0” at 90” of abduction causing discomfort and apprehension. Arthroscopic examination showed a normal labrum with an avulsion of the glenohumeral ligament from the humerus exposing the underlying subscapularis. The edge of the capsule was freshened with a full radius resector, and the burr was used to freshen the insertion site. Four No. zero polydioxanone sutures were placed with a suture hook through the avulsed edge of the capsule through the standard anterior inferior portal.” An additional anterior lateral portal was created 2-cm lateral and 2-cm inferior to the coracoid.
This portal traversed the subscapularis insertion site on the humerus. All four sutures were pulled out through this anterior lateral portal, reapproximating the lateral capsule to its humeral insertion site. Half of the sutures were then separated and passed subfascially below the deltopectoral fascia and half the sutures were passed subcutaneously below the skin (Fig 3). The sutures were tied over the deltopectoral fascia. The patient is 3 years 9 months postoperative without any symptoms of instability or discomfort. The patient returned to all prior physical activity and is currently playing competitive tennis. Case 4 A 16-year-old right-hand dominant boy dislocated his left shoulder at football practice 1 week before
E. M. WOLF ET AL.
604 Superior glenohumeral
ligament
Middle glenohumeral
ligament
Inferior glenohumeral
bile accident 5 months before presentation. She was seen at the time of her second dislocation after a minor fall. Despite conservative treatment with resistive exercises, she continued to have apprehension and pain on abduction and external rotation of her left shoulder. Examination under anesthesia showed gross instability in the anterior-inferior plane. Arthroscopic examination showed the glenohumeral ligament to be normally attached onto the glenoid labrum. There was a large Hill-Sachs lesion noted. When the humeral side was inspected, the entire anterior half of the IGLC including its anterior band was avulsed. This defect was repaired arthroscopically similarly to the repair described above. The patient is 2 years 2 month postoperative, reports no instability, and is able to return to her prior activity level.
Posterior view Case 6 FIG 4. A typical HAGL lesion as viewed posteriorly. defect in the inferior lateral capsule as the glenohumeral avulsed off its humeral insertion site.
There is a ligaments
presentation, The patient was immobilized for 3 weeks. Because of persistent symptoms of instability and the desire to return to football as soon as possible, the patient and his parents opted for surgical fixation 1 month after the initial dislocation. The examination under anesthesia revealed anterior subluxation without any inferior component. Arthroscopy showed a small longitudinal split along the labrum and slight separation from the anterior glenoid. One easily could have mistaken the split in the labrum as the primary pathology but, with further probing, there was no significant displacement. When the humeral side was inspected, a large HAGL lesion was seen. The HAGL lesion extended from the most axillary portion of the anterior half of the IGLC on the humeral head to just inferior to the superior border of the subscapularis tendon (Fig 4). The HAGL lesion was arthroscopically repaired by burring the bed of insertion posterior to the subscapularis, placing five PDS sutures, and pulling the capsule into the old insertion site. The remainder of repair was similar to Case 3. The 36-month follow-up showed the patient without any symptoms of instability and with no difference in strength testing between his two shoulders. He returned to football as a running back. Case 5
The patient is 24-year-old right-handed woman who initially dislocated her left shoulder during an automo-
The patient is a 30-year-old right-handed man who initially dislocated his left shoulder while going for a lay up playing basketball, with the arm abducted and externally rotated. He had subsequently dislocated his left shoulder multiple times requiring an open Bankart procedure. The patient did well for 5 years when he again dislocated his left shoulder playing basketball. On physical examination, he was found to have a positive apprehension sign and lacked approximately 45” of external rotation with the shoulder abducted at 90”. Examination under anesthesia found the patient to have gross instability anteriorly. Arthroscopically, there was capsular redundancy along the glenoid labmm from the prior Bankart repair. There was a large defect in the anterior inferior capsule on the humeral side. This was felt to be the lesion responsible for anterior instability. The defect was repaired arthroscopically as described above. The patient is currently 2 years 2 months postoperative. He denies any pain or loss of motion, and plays basketball regularly.
DISCUSSION The glenohumeral ligaments insert on the glenoid via the labrum, and the adjacent periosteum.1”6 Numerous studies have documented the functional significance of the glenohumeral ligament labral complex (GLLC) in maintaining stability of the shoulder throughout range of motion.11X’6 The subscapularis muscle acts as the principle dynamic anterior stabilizer when the arm is at 0” of abduction. The inferior GLLC (IGLLC) becomes the primary anterior shoulder stabi-
HAGL LESION lizer when the arm is externally rotated and abducted to 90”.16 The gross and histologic anatomy of the IGL has been well described.” The ligament is divided into an anterior, posterior band and the intervening axillary pouch with attachment to the articular edge of the humeral head in a collar-like or ‘ ‘V” shape. l1 The anterior band attaches to the glenoid via the labrum. The avulsion of this GLLC from the glenoid (Bankart lesion) has been established as the primary lesion for anterior inferior instability both clinically and in cadaver stUdies.2,3.8,10.16,23
605
had Hill-Sachs lesions and none had associated rotator cuff disease. Arthroscopic findings were consistent with varying disruptions of the glenohumeral ligaments from the humeral site, rendering the shoulder unstable anteriorly. One patient (Case 6) had had a prior open Bankart procedure. In this patient, the inferior glenohumeral ligament was found to be redundant and well attached to the glenoid rim at time of reoperation, but the humerus can easily sublux anteriorly through the defect at the humeral site. All 6 patients underwent surgical reattachment of their glenohumeral ligament to its humeral insertion site, 2 via open proceRowe et al.*-” reported a 85% incidence of Bankart dures and 4 via arthroscopic procedures. Patients were lesion in patients operated on for traumatic recurrent followed for an average time of 40 months (26 to 52 anterior dislocations, 84% incidence in patients with months). All patients reported no disability and none previous failed anterior stabilizing surgical procedures, had a recurrence at the time of their last clinic visit or and 64% in patients with recurrent anterior shoulder telephone interview. subluxations. The reported percentage of Bankart leIn our study, the 6 shoulders with humeral avulsion sions thought to be responsible for anterior shoulder of the glenohumeral ligament represented a significant instability has varied between 45% and 100%.‘~4~5~12~‘4 portion (35%, 6 of 17) of the group of shoulders (capProcedures designed to obliterate this lesion surgically sular laxity and humeral avulsion) that were unstable have produced excellent results, and confirm its imporand without pathology at the glenoid rim. In the past, tance in anterior instability of the shoulder,8 but not the cause of instability in this group has been postuall cases of recurrent anterior shoulder instability have lated to be capsular laxity, yet there is no accurate, Bankart lesions. Rowe et a1.8found that 15% of recurreliable method to test laxity.8’10 Further proof that a rent dislocations had capsular laxity only, without a HAGL lesion may be responsible for instability was labral avulsion from the glenoid rim. In those cases, seen in Bigliani’s biomechanical study.17 The tensile capsular plication was used to treat these lesions.* property of the IGLC bone-ligament-bone complex Although the Bankart lesion is most often found to was tested to mechanical failure. Three failure sites be responsible for anterior shoulder instability, there were seen: the ligament intrasubstance 35% of the is evidence to suggest that the glenohumeral ligament time; the humeral insertion site 25% of the time; and the glenoid 40% of the time. We believe that this 25% can fail at the humeral insertion site. Nicola” first reported four out of five acute cases of dislocation and reported incidence of HAGL lesion in vitro, as well 6 out of 25 recurrent dislocations where a humeral as our findings, are supportive of the need to carefully avulsion of the capsule occurred. His clinical observaexplore every shoulder arthroscopically for this lesion, tion was confirmed by a subsequent cadaver study especially in those cases where anterior shoulder instawhere he dislocated 50 cadaver shoulders.18 He found bility exists without a frank Bankart lesion. Indeed, that the capsule tore off the humerus with hyperabducclinical study of arthrograms in shoulder dislocations tion (105”) and external rotation, whereas a Bankart have supported two distinct types of lesions: “capsular lesion occurred when hyperabduction was associated rupture” versus “capsular detachment from the glenoid “.‘I This capsular rupture pattern has been estiwith impaction. In our study of 64 shoulders with anterior instability, mated to be 10% in recurrent shoulder dislocations8~2’-23 we found 6 shoulders with HAGL lesions, 47 with and could actually represent the HAGL lesion. Bankart lesions, and 11 with capsular laxity. Analysis We feel the HAGL lesion was the pathology responof our 6 patients with HAGL lesions showed that they sible for anterior instability in our 6 patients, as proper all had one single traumatic episode as the inciting recognition and treatment of HAGL lesions has reevent in the cause of their anterior instability. We canstored glenohumeral stability to all 6 patients. Alnot confirm Nicola’s hypothesis that hyperabduction though this lesion is best identified via diagnostic arthroscopy, studies of acute dislocations with arthrosand external rotation cause glenohumeral ligament failcopy did not note any HAGL lesions, but these studies ure from the humeral side. Initially all patients were were performed without awareness of their potential treated nonoperatively from 1 month to 22 years, and all had multiple recurrences of instability. Two patients presence.*‘**l
606
E. M. WOLF ET AL.
FIG 5. Arthroscopic photograph of a HAGL lesion viewed from the posterior portal. The probe is retracting the avulsed lateral capsule, exposing the underlying subscapularis muscle.
The diagnosis of HAGL lesion as a cause for anterior shoulder instability can be difficult because of the open anterior approach to the unstable shoulder. In attempting to define the plane between the subscapularis tendon and the capsule, the inadvertent entry into the shoulder joint may disguise an actual HAGL lesion. Furthermore, leaving the deeper portion of the subscapularis over the capsule may mask a HAGL lesion. Even with shoulder arthroscopy, this lesion can be overlooked if not specifically searched for in the appropriate area. The arthroscopic finding of an exposed subscapularis muscle (Fig 5) should alert the surgeon to the possibility that a HAGL lesion exists and can potentially cause shoulder instability.
CONCLUSION Disruption of the IGL at the glenoid, humerus, or mid substance will allow the shoulder to dislocate. 2~13~17-19,23 In patients with anterior shoulder instability, without a demonstrable Bankart lesion, the HAGL lesion should be suspected and a well-directed diagnostic arthroscopy performed. The proper recognition and repair of this lesion can restore shoulder stability to the patient.
REFERENCES 1. Adams JC. Recurrent Surg Br 1948;30:26-38.
dislocation
of the shoulder.
J Bone Joint
2. Bankart ASB. Recurrent or habitual dislocation of the shoulder joint. BMJ 1923;2:1132-1133. 3. Bankart ASB. The pathology and treatment of recurrent dislocation of the shoulder joint. Br J Surg 1938;26:23-29. 4. Brav EA. Evaluation of the Putti-Platt reconstruction procedure for recurrent dislocation of the shoulder. J Bone Joint Surg Am 1955;37:731-741. 5. DuToit GT, Roux D. Recurrent dislocation of the shoulder. Twenty-four year study of the Johannesburg stapling operation. .I Bone Joint Surg Am 1956;33:1-12. 6. Glousman R, Jobe F, Tibone .I, Moynes D, Antonelli D, Perry J. Dynamic electromyographic analysis of the throwing shoulder with glenohumeral instability. J Bone Joint Surg Am 1988;70: 220-226. 7. Rowe CR, Sakellarides HT. Factors related to recurrences of anterior dislocations of the shoulder. Clin Orthop 1966;20:4047. 8. Rowe CR, Pate1 D, Southmayd WW. The Bankart procedure: A long-term end result. J Bone Joint Surg Am 1978; 60: 1-16. 9. Rowe CR, Zarins B. Recurrent transient subluxation of the shoulder. J Bone Joint Surg Am 1981;63:863-874. 10. Rowe CR, Zarins B, Ciullo JV. Recurrent anterior dislocation of the shoulder after surgical repair. J Bone Joint Surg Am 1984;66:159-168. 11. O’Brien SJ, Neves MC, Amoczky SP, et al. The anatomy and histology of the inferior glenohumeral ligament complex of the shoulder. Am J Sports iVied 1990; 18:449-456. 12. Palmer I, Widen A. The bone block method for recurrent dislocation of the shoulder joint. J Bone Joint Surg Br 1948;30:5358. 13. Thomas SC, Matsen FA, III. An approach to the repair of avulsion of the glenohumeral ligaments in the management of traumatic anterior glenohumeral instability. J Bone and Joint Surg Am 1989;71:506-513. 14. Watson-Jones R. Note on recurrent dislocation of the shoulder joint. Superior approach causing the only failure in fifty-two operations for repair of the labrum and capsule. J Bone Joint Surg Br 1948; 30:49-52.
HAGL LESION 15. Weber BG, Simpson LA, Hardegger F. Rotation humeral osteotomy for recurrent anterior dislocation of the shoulder associated with a large Hill-Sachs lesion. J Bone J&n Surg Am 1984; 66: 1443-1450. 16. Turkel SJ, Panio MW, Marshall J, Girgis FG. Stabilizing mechanisms preventing anterior dislocation of the glenohumeral joint. J Bone and J&r Surg Am 1981;63:1208-1217. 17. Bialiani LU. Pollock RG. Soslowskv LJ. Flatow EL. Pawluk RJ: Mow VC. Tensile properties of ‘the inferior glenohumeral ligament. / Orthop Res 1992; 10:187-197. 18. Nicola T. Anterior dislocation of the shoulder: The role of the articular capsule. J Bone Joint Surg Am 1942;25:614-616.
607
19. Bach BR, Warren RF, Fronek J. Disruption of the lateral capsule of the shoulder. J Bone JoointSurg Br 1988;70:274-276. 20. Wolf EM, Wilk RM, Richmond JC. Arthroscopic bankart repair using suture anchors. Oper Tech Orthop 1991; 1:184-191. 21. Reeves B. Arthrography of the shoulder. J Bone Joint Surg Br 1966;48:424-435. 22. Nixon JR, Young WS. Arthrography of the shoulder in anterior dislocation: A study of african and asian patients. Injury 1977;9:287-293. 23. Kuriyama S, Fujimaki E. Katagiri T, Uemura S. Anterior dislocation of the shoulder joint sustained through skiing: Arthrographic findings and prognosis. Am J Sports Med 1984; 12:339-346.