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A rare anatomic variant of the superior glenohumeral ligament
Case Report
A Rare Anatomic Variant of the Superior Glenohumeral Ligament Rabindra L. Pradhan, M.D., Eiji Itoi, M.D., Wataru Watanabe, M.D., Shin Yamada, M.D., Hiroyuki Nagasawa, M.D., Togo Shimizu, M.D., Ikuko Wakabayashi, M.D., and Kozo Sato, M.D.
Abstract: The attachment of the superior glenohumeral ligament (SGHL) to the upper pole of the glenoid is variable and 3 types have been described. We report an anatomic variant of SGHL attachment to the upper pole of the glenoid that has not heretofore been reported in the literature. In this case, the SGHL overrode the biceps origin, continued to the superior labrum posteriorly, and had no attachment to the middle glenohumeral ligament or the anterior labrum. This variant was detected during routine arthroscopic examination undertaken before surgery on a rotator cuff tear. Key Words: Superior glenohumeral ligament—Anatomic variant—Shoulder joint.
T
he superior glenohumeral ligament (SGHL) is the most consistent of the 3 glenohumeral ligaments.1 It is present in about 95% to 98% of patients on arthroscopic examination and dissected cadavers.2,3 It attaches to the fovea capitis of the humerus on the medial ridge of the intertubercular groove, curves anteriorly and superiorly toward the superior glenoid, attaches partially on the superior aspect of the anterior superior labrum, and sends other fibers toward the coracoid process.2 Reports in the literature range from describing the Z pattern4 of the anterior capsuloligamentous structure to the SGHL being absent in 10% of cases and originating with the biceps tendon alone or with the middle glenohumeral ligament (MGHL).5 Although the anatomy of SGHL is described as being variable in size and course, only DePalma1 has out-
From the Department of Orthopedic Surgery, Akita University School of Medicine, Akita, Japan. Address correspondence and reprint request to Eiji Itoi, M.D., Department of Orthopedic Surgery, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. E-mail: itoi@med. akita-u.ac.jp © 2001 by the Arthroscopy Association of North America 1526-3231/01/1701-2707$35.00/0 doi:10.1053/jars.2001.17993
lined the 3 types of attachment at the upper pole of the glenoid. We describe a case of what we believe to be a rare anatomic variation of the attachment of the SGHL to the upper glenoid fossa. CASE REPORT A 24-year-old male right-handed machine operator presented with pain in his left shoulder after he had fallen, while diving for a catch, during a baseball game 6 months before. He had been a regular baseball player during his school days and had had occasional pain on the left shoulder that passed away without any treatment. As a catcher, he could throw a ball to about 80 m without any difficulty. Physical examination showed a full, symmetric range of motion of both shoulders with no atrophy of the rotator cuff muscles. All impingement signs were negative and the active compression test, described by O’Brien et al. for labral lesions,6 was not very conclusive. He did not demonstrate any laxity and/or instability in his shoulders. Magnetic resonance imaging (MRI) revealed a partialthickness articular-side tear of the supraspinatus tendon measuring 15 ⫻ 20 mm. The superior labrum on the MRI and magnetic resonance arthrography (MRA)
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 1 (January), 2001: E3
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R. L. PRADHAN ET AL.
images were considered normal. In view of the traumatic origin of the tear and age of the patient, surgery was considered. He underwent arthroscopic examination of the left shoulder followed by mini-open repair of the tear of the rotator cuff. At arthroscopy, fibrillation was observed near the origin of the long head of the biceps tendon and the entire superior labrum was loosely attached to the glenoid with a sublabral recess seen during probing. The SGHL could not be seen at its normal position, but a structure superior to the biceps tendon origin was noted (Fig 1A). After pressing the biceps tendon downward, the SGHL, which overrode the biceps tendon origin, could be seen (Fig 1B). This thickened SGHL continued to the superior labrum posteriorly (Fig 1C). The MGHL was thin whereas the inferior glenohumeral ligament was found to be thick and lax, and both of these ligaments showed scattered
hemorrhagic patches along their course. The cartilage in the glenoid cavity and humeral head was normal. DISCUSSION DePalma in his classic anatomic study of 96 cadavers1 found 3 basic types of attachment of the SGHL to the upper pole of glenoid fossa. He found in 76% (73 of 96 cadavers) that it was attached to the MGHL, the biceps tendon, and the superior labrum. In 20.8% (20 of 96 cadavers) it was attached to the biceps tendon and the superior labrum, and in 1.04% (1 of 96 cadavers) to the biceps tendon only. He also detected considerable disparity in size and believed that the variable visibility from the synovial side could be due to the embryologic development of the ligament from the extracapsular to an intracapsular position.1 The
FIGURE 1. (A) The SGHL seen superior to the biceps origin. (B) The thickened SGHL overriding the biceps tendon origin. (C) Schematic diagram of the thickened SGHL, which overrode the origin of the long head of the biceps tendon. (*SGHL; LHB, long head of biceps tendon.)
ANATOMIC VARIANT OF SGHL SGHL is the most consistent structure among the 3 glenohumeral ligaments.1,2,5,7 During arthroscopy, however, the SGHL may appear to be absent, being hidden behind the biceps tendon.2,8 By retrospectively reviewing approximately 200 arthroscopies performed for various shoulder diseases, this anatomic variant was noticed only in this case. The SGHL is known to be an inferior stabilizer with the arm in adduction9 and an anterior stabilizer with the arm in external rotation.10 These functions may be altered by the anatomic variant. Even clinical symptoms may be related to this anatomic variant. However, without any instability on physical examination and with the smooth recovery seen in this patient after the repair of the cuff defect, we believe that the anatomic variant had no effect on his symptoms. We present this case so that surgeons will be aware of this anatomic variant and that they should not consider such a finding as pathologic. In conclusion, we agree with Gartsman and Taverna11 that glenohumeral arthroscopy is useful before rotator cuff repair or other shoulder surgeries because it helps to detect major or minor pathologic abnormalities or significant anatomic variants, as in this case, that might have been missed otherwise.
3 REFERENCES
1. DePalma AF. Surgery of the shoulder. Ed 3. Philadelphia: JB Lippincott, 1973. 2. Detrisac DA, Johnson LL. Arthroscopic shoulder anatomy: Pathologic and surgical implications. Thoroughfare, NJ: Slack, 1986;36-68. 3. Yeh LR, Kwak S, Kim YS, Pedowitz R, Trudell D, Muhle C, Resnic D. Anterior labroligamentous structures of the glenohumeral joint: Correlation of MR arthrography and anatomic dissection in cadavers. AJR Am J Roentgenol 1998;171:1229-1236. 4. Ferrari DA. Capsular ligaments of the shoulder. Anatomical and functional study of the anterior superior capsule. Am J Sports Med 1990;18:20-24. 5. Beltran J, Bencardino J, Mellado J, Rosenberg ZS, Irish RD. MR arthrography of the shoulder: Variants and pitfalls. RadioGraphics 1997;17:1403-1412. 6. O’Brien SJ, Pagnani MJ, Fealy S, McGlynn SR, Wilson JB. The active compression test: A new and effective test for diagnosing labral tears and acromioclavicular joint abnormality. Am J Sports Med 1998;26:610-613. 7. Steinbeck J., Liljenqvist U, Jerosch J. The anatomy of the glenohumeral ligamentous complex and its contribution to anterior shoulder stability. J Shoulder Elbow Surg 1998;7:122-126. 8. Ellman H, Gartsman GM. Arthroscopic shoulder surgery and related procedures. Philadelphia: Lee & Febiger, 1993. 9. Warner JP, Deng XA, Warren RF, Torzilli PA. Static capsuloligamentous restraints to superior-inferior translation of the glenohumeral joint. Am J Sports Med 1992;20:675-685. 10. O’Connell PW, Nuber GW, Mileski RA, Lautenschlager E. The contribution of the glenohumeral ligaments to anterior stability of the shoulder joint. Am J Sports Med 1990;18:579-584. 11. Gartsman GM, Taverna E. The incidence of glenohumeral joint abnormalities associated with full-thickness, reparable rotator cuff tears. Arthroscopy 1997;13:450-455.
A Rare Anatomic Variant of the Superior Glenohumeral Ligament Rabindra L. Pradhan, M.D., Eiji Itoi, M.D., Wataru Watanabe, M.D., Shin Yamada, M.D., Hiroyuki Nagasawa, M.D., Togo Shimizu, M.D., Ikuko Wakabayashi, M.D., and Kozo Sato, M.D.
Abstract: The attachment of the superior glenohumeral ligament (SGHL) to the upper pole of the glenoid is variable and 3 types have been described. We report an anatomic variant of SGHL attachment to the upper pole of the glenoid that has not heretofore been reported in the literature. In this case, the SGHL overrode the biceps origin, continued to the superior labrum posteriorly, and had no attachment to the middle glenohumeral ligament or the anterior labrum. This variant was detected during routine arthroscopic examination undertaken before surgery on a rotator cuff tear. Key Words: Superior glenohumeral ligament—Anatomic variant—Shoulder joint.
T
he superior glenohumeral ligament (SGHL) is the most consistent of the 3 glenohumeral ligaments.1 It is present in about 95% to 98% of patients on arthroscopic examination and dissected cadavers.2,3 It attaches to the fovea capitis of the humerus on the medial ridge of the intertubercular groove, curves anteriorly and superiorly toward the superior glenoid, attaches partially on the superior aspect of the anterior superior labrum, and sends other fibers toward the coracoid process.2 Reports in the literature range from describing the Z pattern4 of the anterior capsuloligamentous structure to the SGHL being absent in 10% of cases and originating with the biceps tendon alone or with the middle glenohumeral ligament (MGHL).5 Although the anatomy of SGHL is described as being variable in size and course, only DePalma1 has out-
From the Department of Orthopedic Surgery, Akita University School of Medicine, Akita, Japan. Address correspondence and reprint request to Eiji Itoi, M.D., Department of Orthopedic Surgery, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. E-mail: itoi@med. akita-u.ac.jp © 2001 by the Arthroscopy Association of North America 1526-3231/01/1701-2707$35.00/0 doi:10.1053/jars.2001.17993
lined the 3 types of attachment at the upper pole of the glenoid. We describe a case of what we believe to be a rare anatomic variation of the attachment of the SGHL to the upper glenoid fossa. CASE REPORT A 24-year-old male right-handed machine operator presented with pain in his left shoulder after he had fallen, while diving for a catch, during a baseball game 6 months before. He had been a regular baseball player during his school days and had had occasional pain on the left shoulder that passed away without any treatment. As a catcher, he could throw a ball to about 80 m without any difficulty. Physical examination showed a full, symmetric range of motion of both shoulders with no atrophy of the rotator cuff muscles. All impingement signs were negative and the active compression test, described by O’Brien et al. for labral lesions,6 was not very conclusive. He did not demonstrate any laxity and/or instability in his shoulders. Magnetic resonance imaging (MRI) revealed a partialthickness articular-side tear of the supraspinatus tendon measuring 15 ⫻ 20 mm. The superior labrum on the MRI and magnetic resonance arthrography (MRA)
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 1 (January), 2001: E3
1
2
R. L. PRADHAN ET AL.
images were considered normal. In view of the traumatic origin of the tear and age of the patient, surgery was considered. He underwent arthroscopic examination of the left shoulder followed by mini-open repair of the tear of the rotator cuff. At arthroscopy, fibrillation was observed near the origin of the long head of the biceps tendon and the entire superior labrum was loosely attached to the glenoid with a sublabral recess seen during probing. The SGHL could not be seen at its normal position, but a structure superior to the biceps tendon origin was noted (Fig 1A). After pressing the biceps tendon downward, the SGHL, which overrode the biceps tendon origin, could be seen (Fig 1B). This thickened SGHL continued to the superior labrum posteriorly (Fig 1C). The MGHL was thin whereas the inferior glenohumeral ligament was found to be thick and lax, and both of these ligaments showed scattered
hemorrhagic patches along their course. The cartilage in the glenoid cavity and humeral head was normal. DISCUSSION DePalma in his classic anatomic study of 96 cadavers1 found 3 basic types of attachment of the SGHL to the upper pole of glenoid fossa. He found in 76% (73 of 96 cadavers) that it was attached to the MGHL, the biceps tendon, and the superior labrum. In 20.8% (20 of 96 cadavers) it was attached to the biceps tendon and the superior labrum, and in 1.04% (1 of 96 cadavers) to the biceps tendon only. He also detected considerable disparity in size and believed that the variable visibility from the synovial side could be due to the embryologic development of the ligament from the extracapsular to an intracapsular position.1 The
FIGURE 1. (A) The SGHL seen superior to the biceps origin. (B) The thickened SGHL overriding the biceps tendon origin. (C) Schematic diagram of the thickened SGHL, which overrode the origin of the long head of the biceps tendon. (*SGHL; LHB, long head of biceps tendon.)
ANATOMIC VARIANT OF SGHL SGHL is the most consistent structure among the 3 glenohumeral ligaments.1,2,5,7 During arthroscopy, however, the SGHL may appear to be absent, being hidden behind the biceps tendon.2,8 By retrospectively reviewing approximately 200 arthroscopies performed for various shoulder diseases, this anatomic variant was noticed only in this case. The SGHL is known to be an inferior stabilizer with the arm in adduction9 and an anterior stabilizer with the arm in external rotation.10 These functions may be altered by the anatomic variant. Even clinical symptoms may be related to this anatomic variant. However, without any instability on physical examination and with the smooth recovery seen in this patient after the repair of the cuff defect, we believe that the anatomic variant had no effect on his symptoms. We present this case so that surgeons will be aware of this anatomic variant and that they should not consider such a finding as pathologic. In conclusion, we agree with Gartsman and Taverna11 that glenohumeral arthroscopy is useful before rotator cuff repair or other shoulder surgeries because it helps to detect major or minor pathologic abnormalities or significant anatomic variants, as in this case, that might have been missed otherwise.
3 REFERENCES
1. DePalma AF. Surgery of the shoulder. Ed 3. Philadelphia: JB Lippincott, 1973. 2. Detrisac DA, Johnson LL. Arthroscopic shoulder anatomy: Pathologic and surgical implications. Thoroughfare, NJ: Slack, 1986;36-68. 3. Yeh LR, Kwak S, Kim YS, Pedowitz R, Trudell D, Muhle C, Resnic D. Anterior labroligamentous structures of the glenohumeral joint: Correlation of MR arthrography and anatomic dissection in cadavers. AJR Am J Roentgenol 1998;171:1229-1236. 4. Ferrari DA. Capsular ligaments of the shoulder. Anatomical and functional study of the anterior superior capsule. Am J Sports Med 1990;18:20-24. 5. Beltran J, Bencardino J, Mellado J, Rosenberg ZS, Irish RD. MR arthrography of the shoulder: Variants and pitfalls. RadioGraphics 1997;17:1403-1412. 6. O’Brien SJ, Pagnani MJ, Fealy S, McGlynn SR, Wilson JB. The active compression test: A new and effective test for diagnosing labral tears and acromioclavicular joint abnormality. Am J Sports Med 1998;26:610-613. 7. Steinbeck J., Liljenqvist U, Jerosch J. The anatomy of the glenohumeral ligamentous complex and its contribution to anterior shoulder stability. J Shoulder Elbow Surg 1998;7:122-126. 8. Ellman H, Gartsman GM. Arthroscopic shoulder surgery and related procedures. Philadelphia: Lee & Febiger, 1993. 9. Warner JP, Deng XA, Warren RF, Torzilli PA. Static capsuloligamentous restraints to superior-inferior translation of the glenohumeral joint. Am J Sports Med 1992;20:675-685. 10. O’Connell PW, Nuber GW, Mileski RA, Lautenschlager E. The contribution of the glenohumeral ligaments to anterior stability of the shoulder joint. Am J Sports Med 1990;18:579-584. 11. Gartsman GM, Taverna E. The incidence of glenohumeral joint abnormalities associated with full-thickness, reparable rotator cuff tears. Arthroscopy 1997;13:450-455.