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The BHAGL lesion: A new variant of anterior shoulder instability
Case Report
The BHAGL Lesion: A New Variant of Anterior Shoulder Instability Michael A. Oberlander, M.D., Bruce E. Morgan, A.T.C., and Jeffrey L. Visotsky, M.D.
Summary: This article describes a new lesion associated with anterior instability of the shoulder. The bony humeral avulsion of the glenohumeral ligaments (BHAGL) is a rare lesion that may occur after anterior dislocation of the shoulder. There is a bone fragment noted on radiographs of the shoulder that may appear similar to a bony glenoid avulsion. Computed tomography typically will show that the bone is attached to the glenohumeral ligaments and does not originate from the glenoid. Arthroscopy may or may not show the lesion. This variant of anterior shoulder instability may present with impingement or instability symptoms. If symptoms fail to respond to conservative management, treatment through open excision of the bony fragment and reattachment of the glenohumeral ligaments to their origin on the anterior aspect of the humerus is indicated. Key Words: Anterior instability--Humeral avulsion of glenohumeral ligaments with bone.
n his 1938 treatise on the subject, Bankart identified .what he described as the "typical lesion" associated with recurrent anterior shoulder dislocation. According to Bankart "detachment of the glenoid ligament from the anterior margin of the glenoid cavity" was an essential feature of dislocations of the glenohumeral joint. 1,2 Since this pioneering research, numerous other investigators have explored the anatomy, pathology and pathomechanics of the shoulder. Many of these investigators shared Bankart's belief that the lesion that now bears his name was a frequent sequelae of the glenohumeral luxation. However, with the advent and advancement of shoulder arthroscopy, the normal and abnormal anatomy of the shoulder can be more fully appreciated.
I
From the Coastal Orthopaedic Group, Concord, California, U.S.A. Address correspondence and reprint requests to Michael A. Oberlander, M.D., Coastal Orthopaedic Group, 2485 High School Ave., Ste. 208, Concord, CA 94520, U.S.A. © 1996 by the Arthroscopy Association of North America 0749-8063/96/1205-148853.00/0
During arthroscopy, there is no disruption of the normal glenohumeral anatomy, as is required with open surgery. Newly described lesions associated with anterior instability have recently been noted by Neviaser, 3 in his recognition of the anterior labro-ligamentous periosteal sleeve avulsion (ALPSA) lesion and Wolf's documentation of the humeral avulsion of glenohumeral ligament (HAGL) lesion. 4 It is our purpose to describe yet another source of anterior shoulder instability. In 1988 Bach et al. 5 reported two cases of anterior instability caused by the avulsion of the glenohumeral ligaments from the humeral neck. In one of their cases, a bony lesion of underscribed proportion was noted on radiographs. Based on our review of the literature, this is the only such report to date. Through the following case histories, we describe the clinical presentation, a detailed description of the arthroscopic and gross findings, as well as suggested treatment for what we propose be referred to as a bony H A G L (BHAGL) lesion.
CASE HISTORY 1 J. M. is a 25-year-old right-handed man employed as a paramedic. Approximately 1 year before presenta-
Arthroscopy: The Journal of Arthroscopic and Related Surgeo,, Vol 12, No 5 (October), 1996: pp 627-633
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tion, he was assisting a patient into the ambulance when the patient began to fall. In an effort to prevent the patient from falling, the paramedic grabbed him and, in the ensuing commotion, sustained a hyperabduction injury to the right shoulder. The paramedic felt acute pain in the anterior aspect of the shoulder. Subsequently, pain also developed posteriorly. Shortly after his symptoms developed, he was seen at an urgent care facility where he received a subacromial injection for what was thought to be an impingement syndrome. The patient did experience mild relief of his symptoms but continued to have intermittent pain. Having received some benefit from the injection, the patient returned to work whereupon he suffered a second hyperabduction injury while attempting to assist yet another patient. At this point, he began to complain of pain in the lateral and posterior as well as anterior aspects of the shoulder. Accompanying these complaints were reports of intermittent popping and the inability to lift weights in the gym or participate in sports because of shoulder pain. Complaints of mild weakness and the feeling that the shoulder was "popping out" were also reported. On further questioning, the patient did report two previous anterior shoulder dislocations that had occurred while playing high school football. Each was treated by his coach with closed reduction. The patient received no formal rehabilitation following either of these earlier dislocations.
Physical Examination The patient is a well-built, well-developed 25-yearold man who had full shoulder range of motion. Impingement signs were positive with no apparent weakness in the rotator cuff. The patient had a significantly positive apprehension sign and positive relocation test. Anterior, without posterior or inferior, subluxation of the shoulder was appreciated. The contralateral shoulder was normal on examination with similar range of motion and no evidence of instability.
Radiography Initial radiographs (Figs 1 and 2), anteroposterior, axillary, outlet, and internal/external rotation views revealed a 2.5 x 2 cm bony fragment that appeared to be in the inferior recess and consistent with a large bony glenoid avulsion. The humeral head was located normally within the glenoid fossa. Subsequent computed tomograph (CT) scans (Figs 3 and 4) showed a 2 × 3 x 0.5 cm bony fragment posterior to the middle glenohumeral ligament. The scan also revealed a muscular injury to the short head
FIG 1. Anteroposterior radiograph of right shoulder, arrow indicates BHAGL lesion.
of the biceps and coracobrachialis; however, no evidence of rotator cuff injury was seen. The patient subsequently had a diagnostic subacromial injection that did relieve some of the symptoms but did not alleviate the positive apprehension sign. Therefore, it was felt that his impingement symptoms were probably occurring secondary to his anterior instability. The patient did have a formal shoulder rehabilitation program without significant relief of his symptoms. Because of failure to progress with conservative treatment, the patient underwent right shoulder arthroscopy, followed by open anterior capsular labral reconstruction after removal and repair of a BHAGL lesion. Operative P r o c e d u r e Examination under anesthesia revealed anterior subluxation and no evidence of posterior/inferior subluxation. The patient was turned into the lateral decubitus position and right shoulder arthroscopy was performed. Diagnostic arthroscopy showed some fraying of the anterior labrum (Fig 5) without detachment of the labruin or glenohumeral ligaments, a partial thickness tear of the rotator cuff involving the supraspinatus tendon, chondral injury involving the posterior humeral head (Fig 6), and significant synovitis involving the axillary recess (Fig 7). After limited debridement of these lesions, the bony fragment shown on the radiographs and CT scan was not seen from either the anterior or posterior portals. It was felt that this, in all likelihood, was a humeral avulsion of the anterior gle-
SHOULDER INSTABILITY WITH LIGAMENT A VULSION
FIG 2. Anteroposterior radiograph of right shoulder internal rotation, arrow indicates BHAGL lesion.
nohumeral ligaments and an open anterior approach to the shoulder was carried out. The subscapularis was divided proximal to its insertion into the lesser tuberosity and was carefully dissected off of the anterior capsule. The capsule was incised approximately 1 cm medial to the subscapularis and tagged using No. 0 nonabsorbable suture. The large bony lesion was immediately identified, dissected off of the capsule and anterior glenohumeral ligaments, and was found to be consistent with a BHAGL lesion
FIG 3.
CT arthrogram. Circled area denotes BHAGL lesion,
FIG 4.
629
CT arthrogram. Arrow shows lesser tuberosity intact.
(Fig 8) measuring 2.5 x 3 cm (Fig 9). Fibrinous tissue was cleared off of the anterior humerus medial to the lesser tuberosity where this bony avulsion had occurred. The glenohumeral joint was visualized and the glenohumeral ligaments were seen to be attached normally onto the anterior glenoid labrum. The capsule was reattached to the lateral flap of the capsule advancing this slightly laterally. The subscapularis was reattached in its anatomic position and the shoulder closed in routine fashion. The patient was placed in
FIG 5. lesion.
Fraying of anterior labrum without evidence of Bankart
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3! ¸
FIG 6. Chondral injury to posterior aspect of the humeral head. a shoulder immobilizer and treated using a standard rehabilitation protocol with pendulum exercises immediately after surgery. Passive range of motion started 3 weeks and active range of motion 5 weeks after surgery. It has now been 2 years since the surgery and he has had complete resolution of his symptoms with full range of shoulder motion. He has returned to regular duty as a paramedic and to unrestricted sports participation without difficulty. CASE H I S T O R Y 2 K. M. is a 40-year-old man employed as a computer operator. The patient was injured when he sustained a
FIG 8. Bony fragment excised from the humeral attachment of the glenohumeral ligaments.
hyperabduction injury to his right shoulder while playing volleyball. On inspection, the patient's shoulder showed obvious deformity and radiographs taken in the emergency room revealed an anterior/inferior dislocation. The patient underwent a closed reduction with intravenous sedation. Postreduction radiographs showed a Hill-Sachs lesion and a bony excrescence emanating from the anterior/inferior aspect of the humerus. This bony fragment was best visualized on a Garth view (15 ° oblique in the anterior plane of the shoulder [Fig 9]).
Physical Examination Subsequent examination in the office revealed tenderness along the anterior/inferior aspect of the shoulder. The patient had a positive apprehension and a negative sulcus sign. Range of motion was found to be within normal limits.
Treatment
FIG 7. Synovitis in the axillary recess.
The patient was kept in a sling immobilizer for a period of 4 weeks and was subsequently involved in a shoulder strengthening program. The patient made a full recovery and had no recurrent dislocations or subluxations at his 2-year follow-up examination. He has since returned to competitive-level volleyball. Fol-
SHOULDER INSTABILITY WITH LIGAMENT A VULSION
631
Treatment
FIG 9. Garth view of Case 2 with the arrow demarking a small BHAGL lesion.
After failure of conservative treatment, the patient opted for surgical intervention. Examination under anesthesia showed anterior and inferior instability. Arthroscopic examination revealed no labral pathology, but did reveal marked synovitis along the humeral capsular insertion. The rotator cuff was intact. Posterior defects were seen in the humeral head indicative of a Hill-Sachs lesion. The patient was then repreped and draped and open anterior shoulder stabilization performed. At the time of open surgery, the patient was found to have a ligamentous avulsion on the humeral side that included the middle and inferior glenohumeral ligaments with a bony fragment measuring approximately 4 × 6 mm. During surgery, this fragment was reattached using No. 2 nonabsorable sutures placed through a bony trough. Postoperatively the patient was placed in a structured rehabilitation program. He subsequently returned to full duty 5 months after the surgery. Followup at 3 years found complete resolution of shoulder symptoms with no recurrent episodes of dislocation and he had returned to his prior level of sports activities.
DISCUSSION low-up radiographs showed consolidation of the bony avulsion.
These patients had a rare anatomic lesion associated with anterior shoulder instability. The B H A G L (Fig
CASE H I S T O R Y 3 H. T. is a 37-year-old right handed white male who is employed as a construction worker. The patient sustained an anterior/inferior dislocation from a longitudinal traction force when his partner dropped the end of a heavy beam they were carrying. This injury was treated with a closed reduction in the emergency room. The arm was immobilized for three weeks followed by a shoulder rehabilitation program. Subsequent to his rehabilitation the patient went on to have three anterior shoulder dislocations.
Physical Examination Examination revealed full range of motion. Impingement sign was noted with no weakness of the rotator cuff musculature. The patient had both a positive apprehension and a positive sulcus sign.
Radiography A full shoulder series of radiographs revealed a HillSachs lesion and a bony capsular avulsion, which were best visualized on an axillary lateral view (Fig 10).
FIG 10. Axillary lateral view of Case 3 with the arrow pointing to the BHAGL lesion.
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Avulsion of bone w i t h anterior 81enohumeral ligament
Subscapularis
M. A. OBERLANDER ET AL.
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F I G 11. The BHAGL lesion with the subscapularis attached normally on the lesser tuberosity.
11) is unusual in that it may appear as a glenoid avulsion or bony Bankart lesion on radiograph or CT scan and may not be seen arthroscopically. However, one must pursue the clinical suspicion of instability appreciated preoperatively and treat the instability with an open anterior capsular repair after removal or reattachment of the bony fragment. It is felt that the large bony avulsion (noted in Case 1), which was displaced along with fibrous tissue deep to the fragment, may cause impingement-like symptoms in addition to instability. Once the underlying pathology was corrected, all symptoms of impingement and instability resolved. As noted in the introduction, Bankart and others are credited for the original description of the "essential lesion," but other authors have noted a variety of pathological conditions associated with instability. Included among these authors was Platt who, through his own investigations, found " n o single and constant 'Bankartian' lesion capable of being repaired by a standard procedure. ''6 Consistent with Platt's findings, Palmer and Widen, in their more detailed study, identified four separate and distinct pathological conditions involving the anterior glenoid. 7 More recently Baker et al. 8 classified acute lesions occurring secondary to anterior shoulder dislocation into three groups. Their groupings included isolated capsular tears, capsular tears with partial labral detachments, and tears with significant detachments. The pathology described by Baker et al. s was compatible with
the earlier findings of Tijmes et al. 9 who theorized, without apparent regard for severity, that the dislocation would either rupture through the capsule leaving the labrum intact or disengage the labrum from its attachment to the glenoid. While Bankart and others were focusing on the labrum as the site of primary pathology, researchers with differing interests began to address bony lesions. Early investigators into skeletal anomalies occurring as a result of dislocation were Hill and Sachs. 1° Citing research performed over the course of the preceding 60 years Hill and Sachs reported the prevalence of fractures of the greater tuberosity and of " g r o o v e s " located on the articular surface of the humeral head posterior to the tuberosity. In their study, the surgeons described the grooves as being navicular in shape with average measurements of 2.5 cm in length, 1.5 cm in width, and 0.75 cm in depth. According to Rockwood and Matsen, H these grooves, now referred to as HillSachs lesions, are present in 80% of patients reporting a history of recurrent anterior shoulder dislocation. Frequent though they may be, Hill-Sachs lesions are not unique where disturbance of the bony anatomy is concerned. In their 1973 report, Aston and Gregory 12 discuss the existence of chip fractures of the glenoid rim and of a more significant fracture of the same structure. According to the authors, this more consequential, albeit less common fracture, differs from the chip in ways other than simple size. They contend that this more substantial lesion is a pathological manifestation of dislocations that occur when the arm is adducted as opposed to the more common mechanism of abduction and external rotation. The relationship shared between the position of the shoulder and the consequent tissue damage at the time of dislocation was addressed indirectly by Turkel et al. 13 In their investigation of stabilizing mechanisms responsible for the prevention of anterior dislocation, they concluded that at 0 ° of abduction the subscapularis is the principle checkrein to dislocation. From 0 ° to 45 ° of abduction, the subscapularis along with the middle glenohumeral ligament and the anterosuperior fibers of the inferior glenohumeral ligament (IGHL) work cooperatively to support the joint, whereas at 90 °, it is the IGHL that exerts the greatest influence on shoulder stability. Turkel's findings are consistent with the work of McLaughlin TM who, 20 years earlier, had identified the glenohumeral ligaments as the primary "defense against forward displacement of the humerus from the glenoid". Although he makes no distinction as to shoulder position, McLaughlin contended that "virtu-
SHOULDER
INSTABILITY
ally all the suggested causes o f recurrent dislocation reflect s o m e dysfunction o f the tripartite s l i n g " k n o w n as the g l e n o h u m e r a l ligaments. G l e n o h u m e r a l ligament dysfunction is also at the heart o f A L P S A lesion. A c c o r d i n g to Neviaser, 3 this lesion, like the previously described Bankart lesion, destabilizes the anterior inferior supporting structures o f the joint. However, unlike the Bankart lesion, which is characterized b y a rent b e t w e e n the labral c o m p l e x and the glenoid rim, in the A L P S A the anterior inferior glenohumeral ligament along with the labrum and the anterior scapular p e r i o s t e u m avulses and is displaced in a sleeve-like m a n n e r across the anterior glenoid neck. In both the Bankart and A L P S A lesions, the glenohumeral ligaments avulse from their attachments to the anterior glenoid. H o w e v e r , as early as 1942, lesions involving the avulsion o f these ligaments from their attachments to the anatomic neck o f the humerus were described. Referred to as H A G L lesions by W o l f et al. 4 this m o r b i d a n a t o m y was seen in nearly 10% o f patients involved in a 2-year prospective study. Although less frequently seen, the m e r e possibility o f their existence does, according to Wolf, argue for the thorough exploration o f the humeral and glenoid insertions o f the glenohumeral ligaments. In summary, the B H A G L is a variant o f the H A G L lesion, which consists o f a b o n y avulsion o f the glenohumeral ligaments from the humeral side. This lesion m a y or m a y not be found using diagnostic arthroscopy. If the lesion is suspected, it can best be addressed through an open capsular repair. M o s t shoulder surgeons now agree that all anterior instability is not alike and the p a t h o l o g y is variable. To anticipate success after surgical treatment o f instability with elimination
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A VULSION
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o f s y m p t o m s and return to full activity, one must identify and address the underlying pathology, be it a Bankart lesion, capsular stretch, A P S L A lesion, H A G L , or B H A G L lesion.
REFERENCES 1. Bankart ASB. The pathology and treatment of recurrent dislocation of the shoulder joint. Br J Surg 1938;26:23-29. 2. Bankart ASB. Recurrent or habitual dislocation of the shoulder joint. BMJ 1923;2:1132-1133. 3. Neviaser TJ. The anterior labroligamentous periosteal sleeve avulsion lesion: A cause of anterior instability of the shoulder. Arthroscopy 1993;9:17-21. 4. Wolf EM, Cheng, JC, Dickson K. Humeral avulsion of glenohumeral ligaments as a cause of anterior shoulder instability. Arthroscopy 1995; 11:600-607. 5. Bach BR, Warren RF, Fronek J. Disruption of the lateral capsule of the shoulder. J Bone Joint Surg Br 1988;70:274-276. 6. Osmond-Clarke H. Habitual dislocation of the shoulder. J Bone Joint Surg Br 1948;30:19-25. 7. Palmer 1, Widen A. The bone block method for recurrent dislocation of the shoulder joint. J Bone Joint Surgery 1948;30:5358. 8. Baker CL, Uribe JW, Whitman C. Arthroscopic evaluation of acute initial anterior shoulder dislocations. A J Sports Med 1990; 18:25-28. 9. Tijmes J, Loyd HM, Tullos HS. Arthrography in acute shoulder dislocations. South Med J 1979;72:564-567. 10. Hill HA, Sachs MD. The grooved defect of the humeral head. A frequently unrecognized complication of dislocation of the shoulder joint. Radiology 1940;35:690-699. 11. Rockwood CA, Matsen FA. The shoulder. Philadelphia: WB Saunders; 1990:271-272. 12. Aston JW, Gregory FC. Dislocation of the shoulder with significant fracture of the glenoid. J Bone Joint Surg 1973;55: 1531-1533. 13. Turel SJ, Panio MW, Marshall JL, Girgis FG. Stabilizing mechanisms preventing anterior dislocation of the glenohumeral joint. J Bone Joint Surg Am 1981;63:1208-1217. 14. McLaughlin HL. Recurrent anterior dislocation of the shoulder. Am J Surg 1960;99:628-632.
The BHAGL Lesion: A New Variant of Anterior Shoulder Instability Michael A. Oberlander, M.D., Bruce E. Morgan, A.T.C., and Jeffrey L. Visotsky, M.D.
Summary: This article describes a new lesion associated with anterior instability of the shoulder. The bony humeral avulsion of the glenohumeral ligaments (BHAGL) is a rare lesion that may occur after anterior dislocation of the shoulder. There is a bone fragment noted on radiographs of the shoulder that may appear similar to a bony glenoid avulsion. Computed tomography typically will show that the bone is attached to the glenohumeral ligaments and does not originate from the glenoid. Arthroscopy may or may not show the lesion. This variant of anterior shoulder instability may present with impingement or instability symptoms. If symptoms fail to respond to conservative management, treatment through open excision of the bony fragment and reattachment of the glenohumeral ligaments to their origin on the anterior aspect of the humerus is indicated. Key Words: Anterior instability--Humeral avulsion of glenohumeral ligaments with bone.
n his 1938 treatise on the subject, Bankart identified .what he described as the "typical lesion" associated with recurrent anterior shoulder dislocation. According to Bankart "detachment of the glenoid ligament from the anterior margin of the glenoid cavity" was an essential feature of dislocations of the glenohumeral joint. 1,2 Since this pioneering research, numerous other investigators have explored the anatomy, pathology and pathomechanics of the shoulder. Many of these investigators shared Bankart's belief that the lesion that now bears his name was a frequent sequelae of the glenohumeral luxation. However, with the advent and advancement of shoulder arthroscopy, the normal and abnormal anatomy of the shoulder can be more fully appreciated.
I
From the Coastal Orthopaedic Group, Concord, California, U.S.A. Address correspondence and reprint requests to Michael A. Oberlander, M.D., Coastal Orthopaedic Group, 2485 High School Ave., Ste. 208, Concord, CA 94520, U.S.A. © 1996 by the Arthroscopy Association of North America 0749-8063/96/1205-148853.00/0
During arthroscopy, there is no disruption of the normal glenohumeral anatomy, as is required with open surgery. Newly described lesions associated with anterior instability have recently been noted by Neviaser, 3 in his recognition of the anterior labro-ligamentous periosteal sleeve avulsion (ALPSA) lesion and Wolf's documentation of the humeral avulsion of glenohumeral ligament (HAGL) lesion. 4 It is our purpose to describe yet another source of anterior shoulder instability. In 1988 Bach et al. 5 reported two cases of anterior instability caused by the avulsion of the glenohumeral ligaments from the humeral neck. In one of their cases, a bony lesion of underscribed proportion was noted on radiographs. Based on our review of the literature, this is the only such report to date. Through the following case histories, we describe the clinical presentation, a detailed description of the arthroscopic and gross findings, as well as suggested treatment for what we propose be referred to as a bony H A G L (BHAGL) lesion.
CASE HISTORY 1 J. M. is a 25-year-old right-handed man employed as a paramedic. Approximately 1 year before presenta-
Arthroscopy: The Journal of Arthroscopic and Related Surgeo,, Vol 12, No 5 (October), 1996: pp 627-633
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M. A. OBERLANDER ET AL.
tion, he was assisting a patient into the ambulance when the patient began to fall. In an effort to prevent the patient from falling, the paramedic grabbed him and, in the ensuing commotion, sustained a hyperabduction injury to the right shoulder. The paramedic felt acute pain in the anterior aspect of the shoulder. Subsequently, pain also developed posteriorly. Shortly after his symptoms developed, he was seen at an urgent care facility where he received a subacromial injection for what was thought to be an impingement syndrome. The patient did experience mild relief of his symptoms but continued to have intermittent pain. Having received some benefit from the injection, the patient returned to work whereupon he suffered a second hyperabduction injury while attempting to assist yet another patient. At this point, he began to complain of pain in the lateral and posterior as well as anterior aspects of the shoulder. Accompanying these complaints were reports of intermittent popping and the inability to lift weights in the gym or participate in sports because of shoulder pain. Complaints of mild weakness and the feeling that the shoulder was "popping out" were also reported. On further questioning, the patient did report two previous anterior shoulder dislocations that had occurred while playing high school football. Each was treated by his coach with closed reduction. The patient received no formal rehabilitation following either of these earlier dislocations.
Physical Examination The patient is a well-built, well-developed 25-yearold man who had full shoulder range of motion. Impingement signs were positive with no apparent weakness in the rotator cuff. The patient had a significantly positive apprehension sign and positive relocation test. Anterior, without posterior or inferior, subluxation of the shoulder was appreciated. The contralateral shoulder was normal on examination with similar range of motion and no evidence of instability.
Radiography Initial radiographs (Figs 1 and 2), anteroposterior, axillary, outlet, and internal/external rotation views revealed a 2.5 x 2 cm bony fragment that appeared to be in the inferior recess and consistent with a large bony glenoid avulsion. The humeral head was located normally within the glenoid fossa. Subsequent computed tomograph (CT) scans (Figs 3 and 4) showed a 2 × 3 x 0.5 cm bony fragment posterior to the middle glenohumeral ligament. The scan also revealed a muscular injury to the short head
FIG 1. Anteroposterior radiograph of right shoulder, arrow indicates BHAGL lesion.
of the biceps and coracobrachialis; however, no evidence of rotator cuff injury was seen. The patient subsequently had a diagnostic subacromial injection that did relieve some of the symptoms but did not alleviate the positive apprehension sign. Therefore, it was felt that his impingement symptoms were probably occurring secondary to his anterior instability. The patient did have a formal shoulder rehabilitation program without significant relief of his symptoms. Because of failure to progress with conservative treatment, the patient underwent right shoulder arthroscopy, followed by open anterior capsular labral reconstruction after removal and repair of a BHAGL lesion. Operative P r o c e d u r e Examination under anesthesia revealed anterior subluxation and no evidence of posterior/inferior subluxation. The patient was turned into the lateral decubitus position and right shoulder arthroscopy was performed. Diagnostic arthroscopy showed some fraying of the anterior labrum (Fig 5) without detachment of the labruin or glenohumeral ligaments, a partial thickness tear of the rotator cuff involving the supraspinatus tendon, chondral injury involving the posterior humeral head (Fig 6), and significant synovitis involving the axillary recess (Fig 7). After limited debridement of these lesions, the bony fragment shown on the radiographs and CT scan was not seen from either the anterior or posterior portals. It was felt that this, in all likelihood, was a humeral avulsion of the anterior gle-
SHOULDER INSTABILITY WITH LIGAMENT A VULSION
FIG 2. Anteroposterior radiograph of right shoulder internal rotation, arrow indicates BHAGL lesion.
nohumeral ligaments and an open anterior approach to the shoulder was carried out. The subscapularis was divided proximal to its insertion into the lesser tuberosity and was carefully dissected off of the anterior capsule. The capsule was incised approximately 1 cm medial to the subscapularis and tagged using No. 0 nonabsorbable suture. The large bony lesion was immediately identified, dissected off of the capsule and anterior glenohumeral ligaments, and was found to be consistent with a BHAGL lesion
FIG 3.
CT arthrogram. Circled area denotes BHAGL lesion,
FIG 4.
629
CT arthrogram. Arrow shows lesser tuberosity intact.
(Fig 8) measuring 2.5 x 3 cm (Fig 9). Fibrinous tissue was cleared off of the anterior humerus medial to the lesser tuberosity where this bony avulsion had occurred. The glenohumeral joint was visualized and the glenohumeral ligaments were seen to be attached normally onto the anterior glenoid labrum. The capsule was reattached to the lateral flap of the capsule advancing this slightly laterally. The subscapularis was reattached in its anatomic position and the shoulder closed in routine fashion. The patient was placed in
FIG 5. lesion.
Fraying of anterior labrum without evidence of Bankart
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3! ¸
FIG 6. Chondral injury to posterior aspect of the humeral head. a shoulder immobilizer and treated using a standard rehabilitation protocol with pendulum exercises immediately after surgery. Passive range of motion started 3 weeks and active range of motion 5 weeks after surgery. It has now been 2 years since the surgery and he has had complete resolution of his symptoms with full range of shoulder motion. He has returned to regular duty as a paramedic and to unrestricted sports participation without difficulty. CASE H I S T O R Y 2 K. M. is a 40-year-old man employed as a computer operator. The patient was injured when he sustained a
FIG 8. Bony fragment excised from the humeral attachment of the glenohumeral ligaments.
hyperabduction injury to his right shoulder while playing volleyball. On inspection, the patient's shoulder showed obvious deformity and radiographs taken in the emergency room revealed an anterior/inferior dislocation. The patient underwent a closed reduction with intravenous sedation. Postreduction radiographs showed a Hill-Sachs lesion and a bony excrescence emanating from the anterior/inferior aspect of the humerus. This bony fragment was best visualized on a Garth view (15 ° oblique in the anterior plane of the shoulder [Fig 9]).
Physical Examination Subsequent examination in the office revealed tenderness along the anterior/inferior aspect of the shoulder. The patient had a positive apprehension and a negative sulcus sign. Range of motion was found to be within normal limits.
Treatment
FIG 7. Synovitis in the axillary recess.
The patient was kept in a sling immobilizer for a period of 4 weeks and was subsequently involved in a shoulder strengthening program. The patient made a full recovery and had no recurrent dislocations or subluxations at his 2-year follow-up examination. He has since returned to competitive-level volleyball. Fol-
SHOULDER INSTABILITY WITH LIGAMENT A VULSION
631
Treatment
FIG 9. Garth view of Case 2 with the arrow demarking a small BHAGL lesion.
After failure of conservative treatment, the patient opted for surgical intervention. Examination under anesthesia showed anterior and inferior instability. Arthroscopic examination revealed no labral pathology, but did reveal marked synovitis along the humeral capsular insertion. The rotator cuff was intact. Posterior defects were seen in the humeral head indicative of a Hill-Sachs lesion. The patient was then repreped and draped and open anterior shoulder stabilization performed. At the time of open surgery, the patient was found to have a ligamentous avulsion on the humeral side that included the middle and inferior glenohumeral ligaments with a bony fragment measuring approximately 4 × 6 mm. During surgery, this fragment was reattached using No. 2 nonabsorable sutures placed through a bony trough. Postoperatively the patient was placed in a structured rehabilitation program. He subsequently returned to full duty 5 months after the surgery. Followup at 3 years found complete resolution of shoulder symptoms with no recurrent episodes of dislocation and he had returned to his prior level of sports activities.
DISCUSSION low-up radiographs showed consolidation of the bony avulsion.
These patients had a rare anatomic lesion associated with anterior shoulder instability. The B H A G L (Fig
CASE H I S T O R Y 3 H. T. is a 37-year-old right handed white male who is employed as a construction worker. The patient sustained an anterior/inferior dislocation from a longitudinal traction force when his partner dropped the end of a heavy beam they were carrying. This injury was treated with a closed reduction in the emergency room. The arm was immobilized for three weeks followed by a shoulder rehabilitation program. Subsequent to his rehabilitation the patient went on to have three anterior shoulder dislocations.
Physical Examination Examination revealed full range of motion. Impingement sign was noted with no weakness of the rotator cuff musculature. The patient had both a positive apprehension and a positive sulcus sign.
Radiography A full shoulder series of radiographs revealed a HillSachs lesion and a bony capsular avulsion, which were best visualized on an axillary lateral view (Fig 10).
FIG 10. Axillary lateral view of Case 3 with the arrow pointing to the BHAGL lesion.
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Avulsion of bone w i t h anterior 81enohumeral ligament
Subscapularis
M. A. OBERLANDER ET AL.
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~
F I G 11. The BHAGL lesion with the subscapularis attached normally on the lesser tuberosity.
11) is unusual in that it may appear as a glenoid avulsion or bony Bankart lesion on radiograph or CT scan and may not be seen arthroscopically. However, one must pursue the clinical suspicion of instability appreciated preoperatively and treat the instability with an open anterior capsular repair after removal or reattachment of the bony fragment. It is felt that the large bony avulsion (noted in Case 1), which was displaced along with fibrous tissue deep to the fragment, may cause impingement-like symptoms in addition to instability. Once the underlying pathology was corrected, all symptoms of impingement and instability resolved. As noted in the introduction, Bankart and others are credited for the original description of the "essential lesion," but other authors have noted a variety of pathological conditions associated with instability. Included among these authors was Platt who, through his own investigations, found " n o single and constant 'Bankartian' lesion capable of being repaired by a standard procedure. ''6 Consistent with Platt's findings, Palmer and Widen, in their more detailed study, identified four separate and distinct pathological conditions involving the anterior glenoid. 7 More recently Baker et al. 8 classified acute lesions occurring secondary to anterior shoulder dislocation into three groups. Their groupings included isolated capsular tears, capsular tears with partial labral detachments, and tears with significant detachments. The pathology described by Baker et al. s was compatible with
the earlier findings of Tijmes et al. 9 who theorized, without apparent regard for severity, that the dislocation would either rupture through the capsule leaving the labrum intact or disengage the labrum from its attachment to the glenoid. While Bankart and others were focusing on the labrum as the site of primary pathology, researchers with differing interests began to address bony lesions. Early investigators into skeletal anomalies occurring as a result of dislocation were Hill and Sachs. 1° Citing research performed over the course of the preceding 60 years Hill and Sachs reported the prevalence of fractures of the greater tuberosity and of " g r o o v e s " located on the articular surface of the humeral head posterior to the tuberosity. In their study, the surgeons described the grooves as being navicular in shape with average measurements of 2.5 cm in length, 1.5 cm in width, and 0.75 cm in depth. According to Rockwood and Matsen, H these grooves, now referred to as HillSachs lesions, are present in 80% of patients reporting a history of recurrent anterior shoulder dislocation. Frequent though they may be, Hill-Sachs lesions are not unique where disturbance of the bony anatomy is concerned. In their 1973 report, Aston and Gregory 12 discuss the existence of chip fractures of the glenoid rim and of a more significant fracture of the same structure. According to the authors, this more consequential, albeit less common fracture, differs from the chip in ways other than simple size. They contend that this more substantial lesion is a pathological manifestation of dislocations that occur when the arm is adducted as opposed to the more common mechanism of abduction and external rotation. The relationship shared between the position of the shoulder and the consequent tissue damage at the time of dislocation was addressed indirectly by Turkel et al. 13 In their investigation of stabilizing mechanisms responsible for the prevention of anterior dislocation, they concluded that at 0 ° of abduction the subscapularis is the principle checkrein to dislocation. From 0 ° to 45 ° of abduction, the subscapularis along with the middle glenohumeral ligament and the anterosuperior fibers of the inferior glenohumeral ligament (IGHL) work cooperatively to support the joint, whereas at 90 °, it is the IGHL that exerts the greatest influence on shoulder stability. Turkel's findings are consistent with the work of McLaughlin TM who, 20 years earlier, had identified the glenohumeral ligaments as the primary "defense against forward displacement of the humerus from the glenoid". Although he makes no distinction as to shoulder position, McLaughlin contended that "virtu-
SHOULDER
INSTABILITY
ally all the suggested causes o f recurrent dislocation reflect s o m e dysfunction o f the tripartite s l i n g " k n o w n as the g l e n o h u m e r a l ligaments. G l e n o h u m e r a l ligament dysfunction is also at the heart o f A L P S A lesion. A c c o r d i n g to Neviaser, 3 this lesion, like the previously described Bankart lesion, destabilizes the anterior inferior supporting structures o f the joint. However, unlike the Bankart lesion, which is characterized b y a rent b e t w e e n the labral c o m p l e x and the glenoid rim, in the A L P S A the anterior inferior glenohumeral ligament along with the labrum and the anterior scapular p e r i o s t e u m avulses and is displaced in a sleeve-like m a n n e r across the anterior glenoid neck. In both the Bankart and A L P S A lesions, the glenohumeral ligaments avulse from their attachments to the anterior glenoid. H o w e v e r , as early as 1942, lesions involving the avulsion o f these ligaments from their attachments to the anatomic neck o f the humerus were described. Referred to as H A G L lesions by W o l f et al. 4 this m o r b i d a n a t o m y was seen in nearly 10% o f patients involved in a 2-year prospective study. Although less frequently seen, the m e r e possibility o f their existence does, according to Wolf, argue for the thorough exploration o f the humeral and glenoid insertions o f the glenohumeral ligaments. In summary, the B H A G L is a variant o f the H A G L lesion, which consists o f a b o n y avulsion o f the glenohumeral ligaments from the humeral side. This lesion m a y or m a y not be found using diagnostic arthroscopy. If the lesion is suspected, it can best be addressed through an open capsular repair. M o s t shoulder surgeons now agree that all anterior instability is not alike and the p a t h o l o g y is variable. To anticipate success after surgical treatment o f instability with elimination
WITH LIGAMENT
A VULSION
633
o f s y m p t o m s and return to full activity, one must identify and address the underlying pathology, be it a Bankart lesion, capsular stretch, A P S L A lesion, H A G L , or B H A G L lesion.
REFERENCES 1. Bankart ASB. The pathology and treatment of recurrent dislocation of the shoulder joint. Br J Surg 1938;26:23-29. 2. Bankart ASB. Recurrent or habitual dislocation of the shoulder joint. BMJ 1923;2:1132-1133. 3. Neviaser TJ. The anterior labroligamentous periosteal sleeve avulsion lesion: A cause of anterior instability of the shoulder. Arthroscopy 1993;9:17-21. 4. Wolf EM, Cheng, JC, Dickson K. Humeral avulsion of glenohumeral ligaments as a cause of anterior shoulder instability. Arthroscopy 1995; 11:600-607. 5. Bach BR, Warren RF, Fronek J. Disruption of the lateral capsule of the shoulder. J Bone Joint Surg Br 1988;70:274-276. 6. Osmond-Clarke H. Habitual dislocation of the shoulder. J Bone Joint Surg Br 1948;30:19-25. 7. Palmer 1, Widen A. The bone block method for recurrent dislocation of the shoulder joint. J Bone Joint Surgery 1948;30:5358. 8. Baker CL, Uribe JW, Whitman C. Arthroscopic evaluation of acute initial anterior shoulder dislocations. A J Sports Med 1990; 18:25-28. 9. Tijmes J, Loyd HM, Tullos HS. Arthrography in acute shoulder dislocations. South Med J 1979;72:564-567. 10. Hill HA, Sachs MD. The grooved defect of the humeral head. A frequently unrecognized complication of dislocation of the shoulder joint. Radiology 1940;35:690-699. 11. Rockwood CA, Matsen FA. The shoulder. Philadelphia: WB Saunders; 1990:271-272. 12. Aston JW, Gregory FC. Dislocation of the shoulder with significant fracture of the glenoid. J Bone Joint Surg 1973;55: 1531-1533. 13. Turel SJ, Panio MW, Marshall JL, Girgis FG. Stabilizing mechanisms preventing anterior dislocation of the glenohumeral joint. J Bone Joint Surg Am 1981;63:1208-1217. 14. McLaughlin HL. Recurrent anterior dislocation of the shoulder. Am J Surg 1960;99:628-632.