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Humeral and glenoid detachment of the anterior inferior glenohumeral ligament: A cause of anterior shoulder instability
Humeral and glenoid detachment the anterior inferior glenohumeral ligament: A cause of anterior shoulder instability Larry D. Field, MD,
Desmond
Jackson, Miss., and Sydney,
J. Bokor, Australia
MB,
BS, FRACS, and Felix H. Savoie,
of
III, MD,
Recurrent anterior unidirectional shoulder instabilify is mosf common/y associated wifh an avulsion of the glenoid atiachmenf of the lubroligomenfous complex (Bankart lesionj. However, additional capsular injury is oFten considered necessary to allow anterior dislocation. Five patients undergoing surgical stabilization for recurrent anterior instabiliv were noted to have not only a classic Bankart lesion but also a complete disruption of the lateral capsule from the humerul neck. Repair of this “floating” anterior inferior glenohumeral ligament wus accomplished by reatiuchment of the medial and lateral capsular disruptions and has led to excellent postoperative function in these patients. None of the patients has had instab&?/ after an average follow-up of 26 months. Identification and repair of this unusual anatomic lesion is important and if missed may have a significant negative effect on postoperative stability. (J SHOULDER ELBOW SURG J997;6:6- 70.1
A I’
vu slon of the anterior inferior glenohumeral ligament and labral complex from the anterior glenoid rim is commonly seen after anterior shoulder dislocations. Although Bankart’s name remains attached to this anatomic lesion,* Perthes7 also described its importance in recurrent shoulder instability. Many authors now agree the Bankart lesion may not be the only capsular abnormality in this condition4, 5, 8, lo, I3 and that other soft-tissue lesions can contribute to recurrent anterior instability. ‘, 8, 9 Capsular stretching or disruption either in association with anterior labral detachment or in isolation is believed by most investigators to play an important role in recurrent instability. Speer et al.” have recently demonstrated that glenohumeral translations increased only slightly in cadaveric shoulders tested with a mechanical apparatus From the Upper Orthopaedlc elates
Extremity Center,
Service, MISSISSIPPI Sports Medlclne and Western Sydney Orthopaedlc
and Asso-
Reprint re uests. Larry D. Field, MD, Mlsslssippl Sports Medicine and Ort ll opaedlc Center, 132.5 East Fortification St , Jackson, MS 39202 CopyrIght Board
0
1997
10%2746/97/$500+0
6
by Journal
of Shoulder
of Trustees
32/l/77373
and
Elbow
Surgery
after a simulated Bankart lesion was created. These translations were inadequate to allow for glenohumeral dislocation, and these investigators believed that permanent injury to the inferior glenohumeral ligament may also be necessary to produce anterior shoulder dislocation. A biomechanical study by Bigliani et al.3 supports this contention. Bigliani et al.3 separated the inferior glenohumeral ligament into three components and then separately loaded these tissues in tension to failure. They observed three modes of failure including disruption at the glenoid origin (40%), in the mid-substance of the inferior glenohumeral ligament (35%), and at the humeral insertion site (25%). However, even in the cases in which the ligament failed at its glenoid origin, this disruption occurred only after significant elongation of the ligament had occurred, suggesting that permanent plastic deformation of the ligament midsubstance may occur and may contribute to instability. Although failure at the humeral insertion site appears to be uncommon clinically, it has been reported. ” l5 This study is a review of five patients with recurrent anterior shoulder instability in whom both a Bankart lesion and a lateral capsular avulsion were present. This combination of anatomic
J. Shoulder E/bow Surg. Volume 6, Number 1
lesions, which we have termed the “floating AIGHL,” results from detachment of the anterior inferior glenohumeral ligament both medially and laterally, severely limiting the ligament’s contribution to stability.
METHODS Five patients undergoing shoulder surgery for recurrent anterior instability between March 1992 and December 1993 were noted during surgery to have both a Bankart lesion and a lateral avulsion of the capsule. The average age of the four men and one woman in the series was 3 1 years (range 18 to 54 years). Four of the five patients participated regularly in high school or college athletics. Two of the athletes were football players, one was a basketball player, and the other was a rugby player. All five patients had their initial anterior dislocation after a distinct traumatic event characterized by sudden abduction and external rotation of the arm. All patients underwent an extensive rehabilitative exercise program after their initial dislocations. Therapy consisted of a supervised flexibility program along with rotator cuff and scapular strengthening exercises. Exercise regimens were designed not to compromise any of the remaining static restraints while improving function of the dynamic restraints. Exercises were performed in protective arcs so as not to reproduce instability symptoms. All five patients had recurrent anterior dislocations despite this rehabilitation program. The average number of dislocations before surgical intervention was four and ranged from two to eight. The dominant extremity was involved in three of the five cases. None of the patients had undergone shoulder surgery before the index procedure, and no patient had any shoulder symptoms before the initial dislocation. The duration of symptoms before surgery averaged 16 months. These symptoms were primarily related to instability and were characterized by recurrent dislocations, a sense of looseness when participating in sports (four patients) or activities of daily living (one patient), and occasional shoulder pain. Physical examination at initial presentation revealed a positive apprehension sign in all patients when forward pressure was applied to the posterior aspect of the humeral head with the arm passively positioned in 90” of abduction and maximum external rotation. No patient had generalized hyperlaxity on physical examination. Patients were monitored after surgery for an
Field, Bokor, and Savoie
7
average of 26 months (range 18 to 39 months) and were assessed at latest follow-up with the rating scale of Rowe. 9 These scores were then compared with preoperative scores of symptoms, function, and motion. Surgical technique. After general endotracheal anesthesia was induced, the shoulder was examined for stability. Shoulder translations were assessed, and grading was recorded as 1 + when increased translation was present compared with the opposite extremity but was insufficient to cause humeral head subluxation over the glenoid rim. An instability grading of 2+ was assigned when the examiner could subluxate the humeral head over the glenoid but the head spontaneously reduced to its anatomic position when the force was removed. A 3+ grading signified the ability of the examiner to lock the humeral head over the glenoid rim. Examination revealed 2+ anterior translation in four patients and 3+ anterior translation in one patient. One patient had increased posterior translation of 1 +, but no patient had a positive sulcus sign. Shoulder arthroscopy was then performed in the lateral decubitus position in all five patients with anterior and posterior portals. A Bankart lesion was seen in each patient as indicated by a complete labral detachment, typically extending from the mid-glenoid notch inferiorly to approximately the 6 o’clock position on the glenoid face (Figure 1). In addition, all patients were noted to have clear evidence of extensive disruption of the lateral capsule. This detachment typically extended across most of the anterior and inferior humeral neck (Figure 2) and was best seen through the anterior portal. Two patients also had mild posterior labral fraying, and one patient had a small articular surface partial-thickness rotator cuff tear. No posterior or superior labral tears were present. None of the patients had full-thickness rotator cuff tears. All patients had Hill-Sachs lesions. After arthroscopic identification of the intraarticular disease, four of the patients had arthroscopic abrasion of the anterior glenoid neck in preparation for open repair of the Bankart lesion and lateral capsule. After the arthroscopic procedure was performed, the patient was repositioned in the supine position, and the extremity was prepped and draped. An anterior incision with dissection in the deltopectoral interval was then carried out. The subscapularis tendon was then identified and released approximately 1 cm medial to its insertion
8
Field, Bokor, and Savoie
Figure posterior
1
Arthroscoplc portal.
J. Shoulder January/February
view
of
Bankart
lesion
on the lesser tuberosity. No evidence of subscapularis disruption was present in any patient. The interval between the subscapularis tendon and the underlying capsule was then carefully developed. The detached lateral capsule and anterior inferior glenohumeral ligament was then easily identified. Fibrous tissue was present along the medially retracted margin of the detached lateral capsule. This detachment of the lateral capsule was then extended superiorly by sharply incising the capsule. This allowed visualization of the Bankart lesion medially. After the Bankart lesion was repaired with glenoid drill holes in one patient and suture anchors in the remaining four patients, the lateral capsular detachment was then repaired to its anatomic insertion with drill holes and suture anchors laterally. The anterior capsule was overlapped laterally in two patients at the time of lateral capsular repair by incising the anterior capsule horizontally and then advancing the inferior capsular flap superiorly under the superior capsular flap. This lateral capsular advancement was carried out so as to reduce the excessive volume of the axillary recess noted after Bankart lesion repair in
from
present
series
of
patients.
Viewed
Elbow
Surg. 1997
from
these two patients. The subscapularis was then repaired anatomically with interrupted nonabsorbable sutures, and the skin was closed over a drain. Pendulum exercises were started immediately after surgery with progression to 90” of forward flexion. Active assisted rotation exercises limited to 0” of external rotation were begun as well. The sling was removed at an average of 4 weeks, and forward flexion and external rotation exercises were increased. By 12 weeks these patients had generally regained full forward flexion and most external rotation, and a graduated strengthening program for the rotator cuff and scapular muscles was instituted. All patients were allowed to return to full activities by 9 months.
RESULTS Follow-up ranged from 18 months to 39 months and averaged 26 months. Evaluations at latest follow-up with the Rowe rating scale9 were compared with scores obtained by assessment of pre operative symptoms, function, and motion. The parameters of pain, motion, strength, stability, and function were independently assessed, and an
Field, Bokor, and Savoie
1. Shoulder Elbow Surg. Volume 6, Number I
9
Figure
2 Arthroscopic view of lateral capsular dlsruption visualized through anterior portal Humeral head [HH) can be seen below. Detached lateral capsular edge {small arrows) can be seen medially retracted and separated from Its anatomic site of attachment on humeral neck (/urge arrows)
overall score was determined. Before surgery four patients were rated fair (50 to 69), and one was rated good (70 to 84). After surgery all patients achieved an excellent result (85 to 100). Range of motion after surgery was acceptable in all patients and resulted in no functional restrictions. Forward flexion and internal rotation were normal compared with those of the opposite extremity in all five patients. External rotation was equal to the opposite extremity in all but one patient who had failed to regain the final 10” compared with the opposite extremity. No infections or other postoperative complications occurred. All patients had an uneventful postoperative course, and none has undergone further surgery. All were able to return to their presymptomatic level of function. The four athletes were able to return to their respective sports within 1 year. DISCUSSION
Several investigators lateral capsular avulsion
have demonstrated occurs in cadaveric
that ex-
perimental models. 3, 6, l4 Although such a lesion is unusual after dislocation, it has been reported clinically as well. ‘, l5 When present, proper identification of lateral capsular avulsion is important. This would seem particularly important when a Bankart lesion is also present, because repair of the Bankart lesion would fail to adequately retention the anterior glenohumeral ligament when it is also detached laterally. Accurate identification of a lateral capsular avulsion during an open reconstruction may be more difficult than identification of a Bankart lesion. Visualization of the lateral capsular insertion may be limited in an open procedure because of the overlying subscapularis tendon. Separation of the subscapularis from the underlying lateral capsule can be difficult to perform without further distorting the lateral capsular anatomy. Stabilization proce dures that split the fibers of the subscapularis without detachment laterally may make lateral capsular avulsions difficult to reliably identify as well. In fact, it is possible that in some cases in which the lateral capsule appears to have been
10
J. Shoulder Elbow Surg. January/February I997
Field, Bokor, and Savoie
inadvertently penetrated during separation of the overlying subscapularis, the capsular defect may actually be caused by a previous lateral capsular avulsion. Arthroscopy allows excellent and complete visualization of the entire lateral capsule insertion. Any intraarticular capsular disruption or fibrous tissue formation is easily appreciated. All five of the patients in this series had the diagnosis made on arthroscopy before undergoing open repair. Even when the arthroscope is used, unless the lateral capsular insertion is specifically visualized, these disruptions can be missed. These lesions would seem especially easy to overlook both on arthroscopy and at the time of an open procedure when a Bankart lesion is present, because identification of the Bankart lesion confirms the presence of a very common instability pattern for which wellestablished procedures have been developed. Open stabilization procedures that use a medial capsulotomy would seem at particular risk for overlooking a lateral capsular disruption, whereas open stabilization procedures with a lateral capsulotomy may allow a better opportunity to identify these lesions. Little additional attention may be given to the anterior capsular and ligamentous structures, because it might be assumed that repair of the Bankart lesion will effectively retension these structures. However, Bankart repair performed alone in the presence of a lateral capsular disruption would probably fail to adequately retension the anterior inferior glenohumeral ligament and could result in recurrent instability after surgery, because persistent capsular redundancy has been shown clinically to predispose to the failure of operative stabilizations.9, ‘0, l2 The authors recommend visualizing the lateral capsular insertion during arthroscopy in patients with anterior instability symptoms. Arthroscopic assessment of the lateral capsule is particularly important if an open stabilization procedure with a medial capsulotomy is to be used. In addition, during open stabilization procedures for anterior instability with a lateral capsulotomy, the authors
recommend great care be taken to preserve the lateral capsular anatomy underlying the subscap ularis tendon during subscapularis release. An evaluation of the competency of the lateral capsular insertion may then be made before the medial capsular and labral structures are repaired.
REFERENCES Bach B, Warren of the shoulder
RF, FronekJ J Bone Joint
Bankart ASB The pathology catron of the shoulder tornt
Disruption of the lateral Surg Br 1988,708:274-6.
capsule
and treatment of recurrent B J Surg 1938,26 23-9
Biglianr LU, Pollock RG, Soslowsky Mow VC Propertres of the mferror J Orthop Res 1992,lO 187-94
drslo
LJ, Flatow El, Pawluk RJ, glenohumeral ligament
4
Gallre WE, Le Mesuner AB Recurring shoulder. J Bone Jornt Surg Br 1948,30B
5
Moseley HF, Overgaard B The antenor capsular mechanism In recurrent anterror drslocatron of the shoulder Morphologrcal and clmrcal studres wrth special reference to the glenord labrum and the glenohumeral ligaments J Bone Jornt Surg Br 1962,448,9 13-20 Nrcola artrcular
drslocatron 9-14
T Anterior drslocation of the shoulder capsule J Bone Joint Surg 1942,25
Perthes G Uber Operatronen her iron Deutsch Zerschr Chrr 1906,85
the role of the 6 14-8
habrtuelleer 199-205
Schulterluxa-
Rockwood CA Subluxatrons and drslocatrons about der In Rockwood CA. Green DP, editors. Fractures Phrladelphra JB lrpprncott, 1984 722-985. 9
of the
the shoulin adults
Rowe CR Drslocatrons of the shoulder In Rowe CR, editor The shoulder New York Churchrll Livrngstone, 1988 16.5 292.
10
Rowe CR, Pate1 D, Southmayd WW The Bankart procedure A long-term end result study J BoneJoint Surg Am 1978;60A, l-6.
11
Speer KP, Deng X, Borrero S, Torzillr PA, Altchek DA, Warren RF. Bromechanrcal evaluatron of a srmulated Bankart lesion J Bone Joint Surg Am 1994,76A 18 19-26
12
Speer KP, Warren RF Arthroscoprc role for brodegradable materrals 67-76
13
Townly CO The capsular mechanrsm of the shoulder J BoneJomt Surg Am
14
Turkel SJ, Panro MW, Marshall JL, Gurgrs FG Stabilizrng mechanisms preventing anterior drslocatron of the glenohumeral tornt J Bone Joint Surg Am 198 1 ,63A 1208-l 2
15
Wolf EM, Cheng JC, Dickson K Humeral avulsron humeral ligaments as cause of antenor shoulder Arthroscopy 1995,l 1 600-9
shoulder stabrlrzatron Clan Orthop 1993,291 rn recurrent 1950,32A
drslocatron 370-3
of glenornstabrlrty
A
Desmond
Jackson, Miss., and Sydney,
J. Bokor, Australia
MB,
BS, FRACS, and Felix H. Savoie,
of
III, MD,
Recurrent anterior unidirectional shoulder instabilify is mosf common/y associated wifh an avulsion of the glenoid atiachmenf of the lubroligomenfous complex (Bankart lesionj. However, additional capsular injury is oFten considered necessary to allow anterior dislocation. Five patients undergoing surgical stabilization for recurrent anterior instabiliv were noted to have not only a classic Bankart lesion but also a complete disruption of the lateral capsule from the humerul neck. Repair of this “floating” anterior inferior glenohumeral ligament wus accomplished by reatiuchment of the medial and lateral capsular disruptions and has led to excellent postoperative function in these patients. None of the patients has had instab&?/ after an average follow-up of 26 months. Identification and repair of this unusual anatomic lesion is important and if missed may have a significant negative effect on postoperative stability. (J SHOULDER ELBOW SURG J997;6:6- 70.1
A I’
vu slon of the anterior inferior glenohumeral ligament and labral complex from the anterior glenoid rim is commonly seen after anterior shoulder dislocations. Although Bankart’s name remains attached to this anatomic lesion,* Perthes7 also described its importance in recurrent shoulder instability. Many authors now agree the Bankart lesion may not be the only capsular abnormality in this condition4, 5, 8, lo, I3 and that other soft-tissue lesions can contribute to recurrent anterior instability. ‘, 8, 9 Capsular stretching or disruption either in association with anterior labral detachment or in isolation is believed by most investigators to play an important role in recurrent instability. Speer et al.” have recently demonstrated that glenohumeral translations increased only slightly in cadaveric shoulders tested with a mechanical apparatus From the Upper Orthopaedlc elates
Extremity Center,
Service, MISSISSIPPI Sports Medlclne and Western Sydney Orthopaedlc
and Asso-
Reprint re uests. Larry D. Field, MD, Mlsslssippl Sports Medicine and Ort ll opaedlc Center, 132.5 East Fortification St , Jackson, MS 39202 CopyrIght Board
0
1997
10%2746/97/$500+0
6
by Journal
of Shoulder
of Trustees
32/l/77373
and
Elbow
Surgery
after a simulated Bankart lesion was created. These translations were inadequate to allow for glenohumeral dislocation, and these investigators believed that permanent injury to the inferior glenohumeral ligament may also be necessary to produce anterior shoulder dislocation. A biomechanical study by Bigliani et al.3 supports this contention. Bigliani et al.3 separated the inferior glenohumeral ligament into three components and then separately loaded these tissues in tension to failure. They observed three modes of failure including disruption at the glenoid origin (40%), in the mid-substance of the inferior glenohumeral ligament (35%), and at the humeral insertion site (25%). However, even in the cases in which the ligament failed at its glenoid origin, this disruption occurred only after significant elongation of the ligament had occurred, suggesting that permanent plastic deformation of the ligament midsubstance may occur and may contribute to instability. Although failure at the humeral insertion site appears to be uncommon clinically, it has been reported. ” l5 This study is a review of five patients with recurrent anterior shoulder instability in whom both a Bankart lesion and a lateral capsular avulsion were present. This combination of anatomic
J. Shoulder E/bow Surg. Volume 6, Number 1
lesions, which we have termed the “floating AIGHL,” results from detachment of the anterior inferior glenohumeral ligament both medially and laterally, severely limiting the ligament’s contribution to stability.
METHODS Five patients undergoing shoulder surgery for recurrent anterior instability between March 1992 and December 1993 were noted during surgery to have both a Bankart lesion and a lateral avulsion of the capsule. The average age of the four men and one woman in the series was 3 1 years (range 18 to 54 years). Four of the five patients participated regularly in high school or college athletics. Two of the athletes were football players, one was a basketball player, and the other was a rugby player. All five patients had their initial anterior dislocation after a distinct traumatic event characterized by sudden abduction and external rotation of the arm. All patients underwent an extensive rehabilitative exercise program after their initial dislocations. Therapy consisted of a supervised flexibility program along with rotator cuff and scapular strengthening exercises. Exercise regimens were designed not to compromise any of the remaining static restraints while improving function of the dynamic restraints. Exercises were performed in protective arcs so as not to reproduce instability symptoms. All five patients had recurrent anterior dislocations despite this rehabilitation program. The average number of dislocations before surgical intervention was four and ranged from two to eight. The dominant extremity was involved in three of the five cases. None of the patients had undergone shoulder surgery before the index procedure, and no patient had any shoulder symptoms before the initial dislocation. The duration of symptoms before surgery averaged 16 months. These symptoms were primarily related to instability and were characterized by recurrent dislocations, a sense of looseness when participating in sports (four patients) or activities of daily living (one patient), and occasional shoulder pain. Physical examination at initial presentation revealed a positive apprehension sign in all patients when forward pressure was applied to the posterior aspect of the humeral head with the arm passively positioned in 90” of abduction and maximum external rotation. No patient had generalized hyperlaxity on physical examination. Patients were monitored after surgery for an
Field, Bokor, and Savoie
7
average of 26 months (range 18 to 39 months) and were assessed at latest follow-up with the rating scale of Rowe. 9 These scores were then compared with preoperative scores of symptoms, function, and motion. Surgical technique. After general endotracheal anesthesia was induced, the shoulder was examined for stability. Shoulder translations were assessed, and grading was recorded as 1 + when increased translation was present compared with the opposite extremity but was insufficient to cause humeral head subluxation over the glenoid rim. An instability grading of 2+ was assigned when the examiner could subluxate the humeral head over the glenoid but the head spontaneously reduced to its anatomic position when the force was removed. A 3+ grading signified the ability of the examiner to lock the humeral head over the glenoid rim. Examination revealed 2+ anterior translation in four patients and 3+ anterior translation in one patient. One patient had increased posterior translation of 1 +, but no patient had a positive sulcus sign. Shoulder arthroscopy was then performed in the lateral decubitus position in all five patients with anterior and posterior portals. A Bankart lesion was seen in each patient as indicated by a complete labral detachment, typically extending from the mid-glenoid notch inferiorly to approximately the 6 o’clock position on the glenoid face (Figure 1). In addition, all patients were noted to have clear evidence of extensive disruption of the lateral capsule. This detachment typically extended across most of the anterior and inferior humeral neck (Figure 2) and was best seen through the anterior portal. Two patients also had mild posterior labral fraying, and one patient had a small articular surface partial-thickness rotator cuff tear. No posterior or superior labral tears were present. None of the patients had full-thickness rotator cuff tears. All patients had Hill-Sachs lesions. After arthroscopic identification of the intraarticular disease, four of the patients had arthroscopic abrasion of the anterior glenoid neck in preparation for open repair of the Bankart lesion and lateral capsule. After the arthroscopic procedure was performed, the patient was repositioned in the supine position, and the extremity was prepped and draped. An anterior incision with dissection in the deltopectoral interval was then carried out. The subscapularis tendon was then identified and released approximately 1 cm medial to its insertion
8
Field, Bokor, and Savoie
Figure posterior
1
Arthroscoplc portal.
J. Shoulder January/February
view
of
Bankart
lesion
on the lesser tuberosity. No evidence of subscapularis disruption was present in any patient. The interval between the subscapularis tendon and the underlying capsule was then carefully developed. The detached lateral capsule and anterior inferior glenohumeral ligament was then easily identified. Fibrous tissue was present along the medially retracted margin of the detached lateral capsule. This detachment of the lateral capsule was then extended superiorly by sharply incising the capsule. This allowed visualization of the Bankart lesion medially. After the Bankart lesion was repaired with glenoid drill holes in one patient and suture anchors in the remaining four patients, the lateral capsular detachment was then repaired to its anatomic insertion with drill holes and suture anchors laterally. The anterior capsule was overlapped laterally in two patients at the time of lateral capsular repair by incising the anterior capsule horizontally and then advancing the inferior capsular flap superiorly under the superior capsular flap. This lateral capsular advancement was carried out so as to reduce the excessive volume of the axillary recess noted after Bankart lesion repair in
from
present
series
of
patients.
Viewed
Elbow
Surg. 1997
from
these two patients. The subscapularis was then repaired anatomically with interrupted nonabsorbable sutures, and the skin was closed over a drain. Pendulum exercises were started immediately after surgery with progression to 90” of forward flexion. Active assisted rotation exercises limited to 0” of external rotation were begun as well. The sling was removed at an average of 4 weeks, and forward flexion and external rotation exercises were increased. By 12 weeks these patients had generally regained full forward flexion and most external rotation, and a graduated strengthening program for the rotator cuff and scapular muscles was instituted. All patients were allowed to return to full activities by 9 months.
RESULTS Follow-up ranged from 18 months to 39 months and averaged 26 months. Evaluations at latest follow-up with the Rowe rating scale9 were compared with scores obtained by assessment of pre operative symptoms, function, and motion. The parameters of pain, motion, strength, stability, and function were independently assessed, and an
Field, Bokor, and Savoie
1. Shoulder Elbow Surg. Volume 6, Number I
9
Figure
2 Arthroscopic view of lateral capsular dlsruption visualized through anterior portal Humeral head [HH) can be seen below. Detached lateral capsular edge {small arrows) can be seen medially retracted and separated from Its anatomic site of attachment on humeral neck (/urge arrows)
overall score was determined. Before surgery four patients were rated fair (50 to 69), and one was rated good (70 to 84). After surgery all patients achieved an excellent result (85 to 100). Range of motion after surgery was acceptable in all patients and resulted in no functional restrictions. Forward flexion and internal rotation were normal compared with those of the opposite extremity in all five patients. External rotation was equal to the opposite extremity in all but one patient who had failed to regain the final 10” compared with the opposite extremity. No infections or other postoperative complications occurred. All patients had an uneventful postoperative course, and none has undergone further surgery. All were able to return to their presymptomatic level of function. The four athletes were able to return to their respective sports within 1 year. DISCUSSION
Several investigators lateral capsular avulsion
have demonstrated occurs in cadaveric
that ex-
perimental models. 3, 6, l4 Although such a lesion is unusual after dislocation, it has been reported clinically as well. ‘, l5 When present, proper identification of lateral capsular avulsion is important. This would seem particularly important when a Bankart lesion is also present, because repair of the Bankart lesion would fail to adequately retention the anterior glenohumeral ligament when it is also detached laterally. Accurate identification of a lateral capsular avulsion during an open reconstruction may be more difficult than identification of a Bankart lesion. Visualization of the lateral capsular insertion may be limited in an open procedure because of the overlying subscapularis tendon. Separation of the subscapularis from the underlying lateral capsule can be difficult to perform without further distorting the lateral capsular anatomy. Stabilization proce dures that split the fibers of the subscapularis without detachment laterally may make lateral capsular avulsions difficult to reliably identify as well. In fact, it is possible that in some cases in which the lateral capsule appears to have been
10
J. Shoulder Elbow Surg. January/February I997
Field, Bokor, and Savoie
inadvertently penetrated during separation of the overlying subscapularis, the capsular defect may actually be caused by a previous lateral capsular avulsion. Arthroscopy allows excellent and complete visualization of the entire lateral capsule insertion. Any intraarticular capsular disruption or fibrous tissue formation is easily appreciated. All five of the patients in this series had the diagnosis made on arthroscopy before undergoing open repair. Even when the arthroscope is used, unless the lateral capsular insertion is specifically visualized, these disruptions can be missed. These lesions would seem especially easy to overlook both on arthroscopy and at the time of an open procedure when a Bankart lesion is present, because identification of the Bankart lesion confirms the presence of a very common instability pattern for which wellestablished procedures have been developed. Open stabilization procedures that use a medial capsulotomy would seem at particular risk for overlooking a lateral capsular disruption, whereas open stabilization procedures with a lateral capsulotomy may allow a better opportunity to identify these lesions. Little additional attention may be given to the anterior capsular and ligamentous structures, because it might be assumed that repair of the Bankart lesion will effectively retension these structures. However, Bankart repair performed alone in the presence of a lateral capsular disruption would probably fail to adequately retension the anterior inferior glenohumeral ligament and could result in recurrent instability after surgery, because persistent capsular redundancy has been shown clinically to predispose to the failure of operative stabilizations.9, ‘0, l2 The authors recommend visualizing the lateral capsular insertion during arthroscopy in patients with anterior instability symptoms. Arthroscopic assessment of the lateral capsule is particularly important if an open stabilization procedure with a medial capsulotomy is to be used. In addition, during open stabilization procedures for anterior instability with a lateral capsulotomy, the authors
recommend great care be taken to preserve the lateral capsular anatomy underlying the subscap ularis tendon during subscapularis release. An evaluation of the competency of the lateral capsular insertion may then be made before the medial capsular and labral structures are repaired.
REFERENCES Bach B, Warren of the shoulder
RF, FronekJ J Bone Joint
Bankart ASB The pathology catron of the shoulder tornt
Disruption of the lateral Surg Br 1988,708:274-6.
capsule
and treatment of recurrent B J Surg 1938,26 23-9
Biglianr LU, Pollock RG, Soslowsky Mow VC Propertres of the mferror J Orthop Res 1992,lO 187-94
drslo
LJ, Flatow El, Pawluk RJ, glenohumeral ligament
4
Gallre WE, Le Mesuner AB Recurring shoulder. J Bone Jornt Surg Br 1948,30B
5
Moseley HF, Overgaard B The antenor capsular mechanism In recurrent anterror drslocatron of the shoulder Morphologrcal and clmrcal studres wrth special reference to the glenord labrum and the glenohumeral ligaments J Bone Jornt Surg Br 1962,448,9 13-20 Nrcola artrcular
drslocatron 9-14
T Anterior drslocation of the shoulder capsule J Bone Joint Surg 1942,25
Perthes G Uber Operatronen her iron Deutsch Zerschr Chrr 1906,85
the role of the 6 14-8
habrtuelleer 199-205
Schulterluxa-
Rockwood CA Subluxatrons and drslocatrons about der In Rockwood CA. Green DP, editors. Fractures Phrladelphra JB lrpprncott, 1984 722-985. 9
of the
the shoulin adults
Rowe CR Drslocatrons of the shoulder In Rowe CR, editor The shoulder New York Churchrll Livrngstone, 1988 16.5 292.
10
Rowe CR, Pate1 D, Southmayd WW The Bankart procedure A long-term end result study J BoneJoint Surg Am 1978;60A, l-6.
11
Speer KP, Deng X, Borrero S, Torzillr PA, Altchek DA, Warren RF. Bromechanrcal evaluatron of a srmulated Bankart lesion J Bone Joint Surg Am 1994,76A 18 19-26
12
Speer KP, Warren RF Arthroscoprc role for brodegradable materrals 67-76
13
Townly CO The capsular mechanrsm of the shoulder J BoneJomt Surg Am
14
Turkel SJ, Panro MW, Marshall JL, Gurgrs FG Stabilizrng mechanisms preventing anterior drslocatron of the glenohumeral tornt J Bone Joint Surg Am 198 1 ,63A 1208-l 2
15
Wolf EM, Cheng JC, Dickson K Humeral avulsron humeral ligaments as cause of antenor shoulder Arthroscopy 1995,l 1 600-9
shoulder stabrlrzatron Clan Orthop 1993,291 rn recurrent 1950,32A
drslocatron 370-3
of glenornstabrlrty
A