- Email: [email protected]
Open Instability Repair: The Anterior-Inferior Capsular Shift
Open Instability Repair: The Anterior-Inferior Capsular Shift Maher J. Bahu, MD, Aaron S. Covey, MD, Louis U. Bigliani, MD, and Katie B. Vadasdi, MD Shoulder dislocations in the young patient have been shown to have a high risk of recurrent dislocation or symptomatic subluxation. Repeated episodes of instability can be disabling in the short term and lead to long term degenerative changes of the glenohumeral joint. The associated injuries involve an avulsion of the anterior-inferior glenoid labrum as well as deformation of the capsule. There is a higher rate of failure if these injuries are not addressed at the time of surgery. This article describes our technique of surgical management of recurrent anterior instability: the anterior-inferior capsular shift. This approach includes both capsular shift as well as reattachment of the displaced labrum. This technique allows for titration of the capsular plication for the individual patient. Oper Tech Orthop 18:62-67 © 2008 Elsevier Inc. All rights reserved. KEYWORDS shoulder, instability, insufficiency, capsular shift, open repair
S
houlder dislocations in young patients have a high risk of recurring or causing symptomatic subluxation after the initial traumatic event.1 Recurrent shoulder instability likely has a greater affect on quality of life than has been previously reported.2 Repeated instability episodes can be disabling and lead to permanent degenerative changes of the glenohumeral joint. Bankart3 described the essential lesion of the dislocating shoulder as an avulsion of the anterior-inferior glenoid labrum, but recurrent instability has since been shown to be the result of deformation of the capsule as well.4 A significantly higher rate of failure may be expected if both of these injuries are not addressed at the time of surgery.5,6 Open instability procedures have been shown to restore preinjury levels of function and quality of life to near normal levels.2 This article describes our technique for the surgical management of recurrent anterior instability: the anterior-inferior capsular shift. This procedure was initially described by Neer and Foster7 as a treatment for inferior and multidirectional instability, but our approach has been modified for the surgical treatment of anterior instability and includes reattachment of a displaced labrum. An advantage of this technique includes exact titration of the capsular plication to match each patient’s individual needs. Also, our technique has a reported history of success in longer-term follow-up.8
New York Orthopaedic Hospital, Columbia-Presbyterian Medical Center, New York, NY. Address reprint requests to Louis U. Bigliani, MD, 622 West 168th Street, PH-11, New York, NY 10032. E-mail: [email protected]
62
1048-6666/08/$-see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1053/j.oto.2008.07.004
Surgical repair is recommended for patients with disability and pain caused by instability despite adequate nonoperative treatment. The choice of arthroscopic or open stabilization is largely a matter of surgeon preference. Previously, arthroscopic techniques were associated with higher recurrence rates than open repair,9,10 and open repair remains the gold standard to compare the results of improving arthroscopic techniques. More recent reports show arthroscopic recurrence rates similar to open repair, particularly when there is no bony deficit. We favor open repair in revision cases or when bone deficiency exists. The open anterior-inferior capsular shift is a reliable method for treating a wide variety of symptomatic shoulder instability patients. Voluntary instability, active infection, and paralysis are contraindications to this procedure.11
Technique Rationale for Anterior-Inferior Capsular Shift The inferior capsular shift in its classic form was designed to treat multidirectional instability of the shoulder; it was first described by Neer and Foster.7 This procedure reduces capsular volume globally and restores tension on the glenohumeral ligaments. Furthermore, with proper technique, the posterior capsule can be tensioned from an anterior approach. This involves shifting the anterior and inferior capsule superiorly after extensively releasing the capsule from the humerus. For unidirectional anterior instability, the capsular shift is modified with less extensive capsular mobilization as compared with Neer’s original method.
Open instability repair
63 detected and treated with a humeral-based shift and potentially overlooked with the glenoid-based procedure.
Surgical Technique
Figure 1 The deltopectoral interval is identified and incised by using a needle-tip cautery device. The cephalic vein is retracted laterally with the deltoid.
Our preferred method of anterior-inferior capsular shift has several strengths. Exact titration of the capsular tensioning to the desired amount is achieved so varying degrees of capsular redundancy in different patients may be precisely corrected. The key maneuver is to adjust the degree of capsular takedown around the humeral neck as the full extent of the inferior pouch is appreciated. The desired amount of the capsule to shift is based on the size of the inferior pouch and the degree of laxity. This is a large advantage with this technique because our experience has found that most patients do not fall into the classic two distinct categories of traumatic anterior or atraumatic multidirectional instability but rather represent a spectrum of pathology. Our “T” capsulorrhaphy allows the surgeon to independently adjust capsular tension in the medial to lateral direction as well as in the more important inferior to superior plane.6 Furthermore, the surgeon must guard against overtensioning in the medial to lateral direction, which can lead to a loss of external rotation. Medial redundancy of the anterior capsule can be assessed and treated if necessary with a crimping or “barrel” stitch. Our results have shown that using this crimping stitch to deal with medial redundancy has led to outcomes similar to those in other patients with instability.12 This is important because patients with medial capsular redundancy have been shown to have had a longer duration of symptoms and more repeat dislocations.12 We have not used a “T” capsulorrhaphy when we used a barrel stitch. At our institution, a humeral-based shift is preferred over the glenoid-based variation of this procedure. The capsule is shaped like a funnel with a larger circumference laterally (on the humeral side) than medially. Therefore, a laterally based capsular incision facilitates greater shifting of the tissue for a larger distance. This provides more capsular overlap and allows for a greater reduction in capsular volume than glenoidbased shifts.13 Also, the axillary nerve is closer to the medial capsule, which may put it at greater risk during a medially based shift. Finally, humeral avulsion of the capsule is best
The patient is placed into a modified beach-chair position with the head of the bed elevated 30°. We prefer interscalene regional anesthesia with intravenous sedation. Supplemental local anesthesia is often necessary, especially when operating in the T2 sensory dermatomal distribution at the inferiormedial aspect of the wound. An axillary incision is used, which proves to be more cosmetically appealing than a traditional deltopectoral incision. The incision is approximately 6 cm and placed in the axillary crease and directed toward the coracoid. Once the superficial incision is completed, the deltopectoral interval is identified and the cephalic vein retracted laterally with the deltoid Fig. 1. If additional inferior exposure is needed, the upper 1/2 to 1 cm of the pectoralis major insertion is released and tagged with nonabsorbable suture. If performed, repair of the released portion is done at the conclusion of the procedure. The coracoid is identified, and the clavipectoral fascia is incised just lateral to the strap muscles. The strap muscles are then retracted medially, and aggressive retraction of the strap muscles is avoided to prevent injury to the musculocutaneous nerve. The coracoacromial ligament is identified, and a small wedge of the lateral band is ellipsed to improve superior exposure (Fig. 2). A complete anterior bursectomy is then performed to easily identify the upper and lower borders of the subscapularis muscle. The anterior circumflex humeral artery and the two veins that run with it mark the lower border of the subscapularis. These vessels are then coagulated. The upper border is identified by visualizing and palpating the rotator interval. The subscapularis is incised 1 cm medial to its insertion onto the lesser tuberosity in its tendinous portion (Fig. 3). This
Figure 2 The anterior-lateral leading edge of the coracoacromial ligament (clamped) is resected for improved superior exposure.
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M.J. Bahu et al
Figure 3 The subscapularis is incised approximately 1 cm medial to its insertion, leaving a cuff of tissue laterally (arrow) for subsequent repair.
Figure 5 By using blunt dissection, the confluent superior portion of the subscapularis can be teased from the anterior capsule using the inferior split to identify the correct plane of dissection.
will ensure tendon to tendon apposition for later repair. Next, the subscapularis is separated from the underlying glenohumeral capsule. This is the most important and demanding step of the procedure. The upper portion of the subscapularis is confluent with the capsule, but, inferiorly, the capsule and subscapularis muscle are typically separate entities14 (Fig. 4). Blunt dissection at the inferior aspect of the subscapularis allows identification of the plane between the two structures. Once the plane is defined, an elevator and Mayo scissors are used to tease the confluent portion of the subscapularis off the anterior capsule (Figs. 5 and 6). Tag sutures are placed to keep traction on the subscapularis tendon during separation. The axillary nerve should be protected during subscapularis release. The “tug test”15 may be helpful in identifying the nerve. Adducting and externally
rotating the humerus helps to move the axillary nerve further from the operative dissection. Once the subscapularis is completely released, the capsule is incised approximately 0.5 cm medial to the subscapularis stump, leaving an adequate cuff of capsular tissue for subsequent repair (Fig. 7). The capsular incision begins superiorly at the rotator interval and continues inferiorly with traction sutures placed in the free edge (Fig. 8). Once the neck of the humerus is reached, the arm is externally rotated and the capsule released off the neck with a scalpel. The amount of capsule released at the inferior neck is determined by the degree of capsular redundancy. The surgeon places a finger in the inferior pouch and pulls on the tag sutures. If the pouch is obliterated and the finger is completely pushed out of the pouch with tension on the tag sutures, then an adequate amount of capsule has been released. It is important to recognize that the inferior capsule splits into two layers and has a dual attachment to the inferior humeral neck (Fig. 9). To perform an adequate shift, the inner and outer layers must be released from the neck of the
Figure 4 Inferiorly, the subscapularis muscle is not adherent to the capsule and the two structures can be more easily separated. The dotted arrow points to the confluent subscapularis tendon and anterior capsule superiorly. The dashed arrow points to the plane developed inferiorly between the two. The solid arrow points to the subscapularis muscle undersurface.
Figure 6 Mayo scissors can then be used to complete the separation.
Open instability repair
Figure 7 The capsule is sharply incised, taking care not to damage the humeral head cartilage below. An adequate cuff of tissue is left behind for subsequent repair.
65
Figure 9 Dual attachment of the inferior capsule on the humeral neck (arrows).
humerus to prevent capsular tethering14 (Fig. 10). After both layers are released, the inferior redundant pouch is obliterated with superior traction. At this point, the external surface of the capsule is inspected and residual attachments of the subscapularis are removed. Often these attachments lie far medially and can prevent complete shifting if left intact. A Fukuda retractor is placed into the glenohumeral joint, and the humerus is moved posteriorly to allow visualization of the glenoid and labrum. If a Bankart lesion is identified, it is managed at this time. The anterior-inferior glenoid rim lesion is prepared with a curette to bleeding bone. Suture anchors are placed at the articular cartilage/scapular neck margin. Care is taken to avoid placing these suture anchors on the medial glenoid neck. Depending on the size of the lesion, multiple anchors are needed, and the typical number is three. The sutures are passed through the capsule from inside to outside and then tied. If there is excessive medial capsular redundancy or the anterior inferior labrum has been attenuated, an anterior crimping (barrel) stitch is placed. The
stitch is started on the external side of the capsule at the capsule-labral junction. It is passed through the capsule and then back out the capsule in a mattress fashion (Fig. 11). Once tied, the anterior-medial redundancy is obliterated, and a bolster to the anterior labrum is created (Fig. 12). The labrum is palpated to appreciate the recreated labral bumper. As mentioned previously, one of the advantages of a humeral-based shift is the ability to titrate the amount of capsular shift to the pathology identified intraoperatively. For patients with isolated anterior instability, only the anterior capsule is mobilized. However, patients with bidirectional (anterior and inferior) instability have a large inferior pouch that needs to be reduced. In these cases, the anterior capsule is split horizontally between the inferior and middle glenohumeral ligaments and overlapped in a pants-over-vest fashion to further reduce volume. The arm is positioned to 20° or 30° of abduction and 20° or 30° of external rotation during capsular reattachment. More abduction and external rotation are used in overhead athletes. Less abduction and external rotation are used in pa-
Figure 8 The capsular incision is continued inferiorly by using tag stitches on the released anterior capsule to apply traction.
Figure 10 Release of the dual inferior capsular attachment, allowing a complete shift of the capsule.
M.J. Bahu et al
66
Figure 11 An anterior crimping (barrel) stitch is used to decrease the redundancy of the anterior-inferior capsule. This is a mattress suture started on the superficial side of the capsule. Figure 13 The anterior-inferior capsule is advanced superiorly and reattached to the capsular sleeve preserved on the humeral neck.
tients with large Hill-Sachs lesions or anterior glenoid bone deficiency. The inferior aspect of the capsule is held under mild tension with tag sutures, advanced superiorly (thus, the capsular shift), and reattached in its new position with simple sutures (Fig. 13). If the horizontal “T” has been made, then the horizontal limb is repaired in a pants-over-vest fashion after the inferior portion is secured. The superior portion of the capsule is repaired last. The rotator interval is repaired if the preoperative sulcus sign remained positive in external rotation. The surgeon must be aware of overtightening the capsule. This will limit external rotation, particularly in overhead-throwing athletes. The subscapularis is closed anatomically followed by a layered skin closure. Drains are not routinely used. A sling and swathe are applied in the operating room.
Rehabilitation A sling is used postoperatively for 6 weeks to protect the repair. Exercises are initiated within 10 days beginning with pendulums. Range-of-motion limits are determined intraoperatively, but, in general, elevation to 100° and external rotation to 15° are begun from 10 days to 2 weeks. From 2 to 4 weeks, elevation to 140° and external rotation to 30° are allowed. At this time, gentle resistive exercises are initiated. At 4 to 6 weeks, elevation is increased to 165°, external rotation to 40°, and resistive exercises are slightly increased. After 6 weeks, external rotation is increased further, and terminal elevation stretching is permitted. The goals are to achieve full motion over several months and to avoid failure by advancing the rehabilitation too quickly. These patients should have their progression monitored closely, and return to vigorous sports is generally delayed for a minimum of 6 months.
Results
Figure 12 Once tied, the barrel stitch reduces anterior-medial capsular redundancy and an anterior-inferior bolster is created. This can be palpated.
In a study performed at our institution, 68 shoulders in 63 athletic patients with anterior-inferior glenohumeral instability underwent an anterior-inferior capsular shift procedure, including the dominant arm of 31 overhead-throwing athletes. Good or excellent results were achieved in 94% of patients, including 75% returning to their previous level of athletic competition. External rotation loss averaged 7°, and only two patients had recurrence of dislocation.11 In a separate study of patients undergoing capsular shift, 38 patients with medial redundancy who received a crimping “barrel” suture were compared with 40 patients who did not have redundancy. Despite a higher number of dislocations and a longer duration of symptoms preoperatively, the incidence of good and excellent results and postoperative Rowe scores were similar for both groups.12
Open instability repair
Conclusion Our understanding of the pathophysiology of anterior shoulder instability has improved in the past decade. The primary pathology is related to labral detachment, capsular redundancy, and associated loss of tension of the glenohumeral ligaments. When nonoperative intervention has failed, treatment should be directed at restoring the original anatomy. An anatomic reconstruction and early range of motion will yield successful results in patients with anterior shoulder instability. The inferior capsular shift as described by Neer and Foster7 is preferred because the amount of capsule being shifted can easily be titrated to treat the amount and direction of pathology found at surgery. The procedure allows excellent exposure of the glenoid and the ability to individualize the repair. If performed meticulously, the anterior-inferior capsular shift provides excellent enduring results while allowing patients to return to full activity.
References 1. Hovelius L: Shoulder dislocation in Swedish ice hockey players. Am J Sports Med 6:373-77, 1978 2. Meller R, Krettek C, Gösling T, et al: Recurrent shoulder instability among athletes: Changes in quality of life, sports activity, and muscle function following open repair. Knee Surg Sports Traumatol Arthrosc 15:295-304, 2007 3. Bankart A: The pathology and treatment of recurrent dislocation of the shoulder joint. Br Med J 26:23-29, 1938 4. Townley CO: The capsular mechanism in recurrent dislocation of the shoulder. J Bone Joint Surg Am 32A:370-380, 1950
67 5. Rowe CR, Zarins B, Ciullo JV: Recurrent anterior dislocation of the shoulder after surgical repair. Apparent causes of failure and treatment. J Bone Joint Surg Am 66:159-168, 1984 6. Levine WN, Flatow EL: The pathophysiology of shoulder instability. Am J Sports Med 28:910-917, 2000 7. Neer CS 2nd, Foster CR: Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder. A preliminary report. J Bone Joint Surg Am 62:897-908, 1980 8. Pollock RG, Owens JM, Flatow EL, et al: Operative results of the inferior capsular shift procedure for multidirectional instability of the shoulder. J Bone Joint Surg Am 82A:919-928, 2000 9. Lenters TR, Franta AK, Wolf FM, et al: Arthroscopic compared with open repairs for recurrent anterior shoulder instability. A systematic review and meta-analysis of the literature. J Bone Joint Surg Am 89: 244-254, 2007 10. Burkhart SS, De Beer JF: Traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repairs: Significance of the inverted-pear glenoid and the humeral engaging Hill-Sachs lesion. Arthroscopy 16:677-694, 2000 11. Bigliani LU, Kurzweil PR, Schwartzbach CC, et al: Inferior capsular shift procedure for anterior-inferior shoulder instability in athletes. Am J Sports Med 22:578-584, 1994 12. Ahmad CS, Freehill MQ, Blaine TA, et al: Anteromedial capsular redundancy and labral deficiency in shoulder instability. Am J Sports Med 31:247-252, 2003 13. Miller MD, Larsen KM, Luke T, et al: Anterior capsular shift volume reduction: An in vitro comparison of 3 techniques. J Shoulder Elbow Surg 12:350-354, 2003 14. Sugalski MT, Wiater JM, Levine WN, et al: An anatomic study of the humeral insertion of the inferior glenohumeral capsule. J Shoulder Elbow Surg 14:91-95, 2005 15. Flatow EL, Bigliani LU: Tips of the trade. Locating and protecting the axillary nerve in shoulder surgery: the tug test. Orthop Rev 21:503505, 1992
S
houlder dislocations in young patients have a high risk of recurring or causing symptomatic subluxation after the initial traumatic event.1 Recurrent shoulder instability likely has a greater affect on quality of life than has been previously reported.2 Repeated instability episodes can be disabling and lead to permanent degenerative changes of the glenohumeral joint. Bankart3 described the essential lesion of the dislocating shoulder as an avulsion of the anterior-inferior glenoid labrum, but recurrent instability has since been shown to be the result of deformation of the capsule as well.4 A significantly higher rate of failure may be expected if both of these injuries are not addressed at the time of surgery.5,6 Open instability procedures have been shown to restore preinjury levels of function and quality of life to near normal levels.2 This article describes our technique for the surgical management of recurrent anterior instability: the anterior-inferior capsular shift. This procedure was initially described by Neer and Foster7 as a treatment for inferior and multidirectional instability, but our approach has been modified for the surgical treatment of anterior instability and includes reattachment of a displaced labrum. An advantage of this technique includes exact titration of the capsular plication to match each patient’s individual needs. Also, our technique has a reported history of success in longer-term follow-up.8
New York Orthopaedic Hospital, Columbia-Presbyterian Medical Center, New York, NY. Address reprint requests to Louis U. Bigliani, MD, 622 West 168th Street, PH-11, New York, NY 10032. E-mail: [email protected]
62
1048-6666/08/$-see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1053/j.oto.2008.07.004
Surgical repair is recommended for patients with disability and pain caused by instability despite adequate nonoperative treatment. The choice of arthroscopic or open stabilization is largely a matter of surgeon preference. Previously, arthroscopic techniques were associated with higher recurrence rates than open repair,9,10 and open repair remains the gold standard to compare the results of improving arthroscopic techniques. More recent reports show arthroscopic recurrence rates similar to open repair, particularly when there is no bony deficit. We favor open repair in revision cases or when bone deficiency exists. The open anterior-inferior capsular shift is a reliable method for treating a wide variety of symptomatic shoulder instability patients. Voluntary instability, active infection, and paralysis are contraindications to this procedure.11
Technique Rationale for Anterior-Inferior Capsular Shift The inferior capsular shift in its classic form was designed to treat multidirectional instability of the shoulder; it was first described by Neer and Foster.7 This procedure reduces capsular volume globally and restores tension on the glenohumeral ligaments. Furthermore, with proper technique, the posterior capsule can be tensioned from an anterior approach. This involves shifting the anterior and inferior capsule superiorly after extensively releasing the capsule from the humerus. For unidirectional anterior instability, the capsular shift is modified with less extensive capsular mobilization as compared with Neer’s original method.
Open instability repair
63 detected and treated with a humeral-based shift and potentially overlooked with the glenoid-based procedure.
Surgical Technique
Figure 1 The deltopectoral interval is identified and incised by using a needle-tip cautery device. The cephalic vein is retracted laterally with the deltoid.
Our preferred method of anterior-inferior capsular shift has several strengths. Exact titration of the capsular tensioning to the desired amount is achieved so varying degrees of capsular redundancy in different patients may be precisely corrected. The key maneuver is to adjust the degree of capsular takedown around the humeral neck as the full extent of the inferior pouch is appreciated. The desired amount of the capsule to shift is based on the size of the inferior pouch and the degree of laxity. This is a large advantage with this technique because our experience has found that most patients do not fall into the classic two distinct categories of traumatic anterior or atraumatic multidirectional instability but rather represent a spectrum of pathology. Our “T” capsulorrhaphy allows the surgeon to independently adjust capsular tension in the medial to lateral direction as well as in the more important inferior to superior plane.6 Furthermore, the surgeon must guard against overtensioning in the medial to lateral direction, which can lead to a loss of external rotation. Medial redundancy of the anterior capsule can be assessed and treated if necessary with a crimping or “barrel” stitch. Our results have shown that using this crimping stitch to deal with medial redundancy has led to outcomes similar to those in other patients with instability.12 This is important because patients with medial capsular redundancy have been shown to have had a longer duration of symptoms and more repeat dislocations.12 We have not used a “T” capsulorrhaphy when we used a barrel stitch. At our institution, a humeral-based shift is preferred over the glenoid-based variation of this procedure. The capsule is shaped like a funnel with a larger circumference laterally (on the humeral side) than medially. Therefore, a laterally based capsular incision facilitates greater shifting of the tissue for a larger distance. This provides more capsular overlap and allows for a greater reduction in capsular volume than glenoidbased shifts.13 Also, the axillary nerve is closer to the medial capsule, which may put it at greater risk during a medially based shift. Finally, humeral avulsion of the capsule is best
The patient is placed into a modified beach-chair position with the head of the bed elevated 30°. We prefer interscalene regional anesthesia with intravenous sedation. Supplemental local anesthesia is often necessary, especially when operating in the T2 sensory dermatomal distribution at the inferiormedial aspect of the wound. An axillary incision is used, which proves to be more cosmetically appealing than a traditional deltopectoral incision. The incision is approximately 6 cm and placed in the axillary crease and directed toward the coracoid. Once the superficial incision is completed, the deltopectoral interval is identified and the cephalic vein retracted laterally with the deltoid Fig. 1. If additional inferior exposure is needed, the upper 1/2 to 1 cm of the pectoralis major insertion is released and tagged with nonabsorbable suture. If performed, repair of the released portion is done at the conclusion of the procedure. The coracoid is identified, and the clavipectoral fascia is incised just lateral to the strap muscles. The strap muscles are then retracted medially, and aggressive retraction of the strap muscles is avoided to prevent injury to the musculocutaneous nerve. The coracoacromial ligament is identified, and a small wedge of the lateral band is ellipsed to improve superior exposure (Fig. 2). A complete anterior bursectomy is then performed to easily identify the upper and lower borders of the subscapularis muscle. The anterior circumflex humeral artery and the two veins that run with it mark the lower border of the subscapularis. These vessels are then coagulated. The upper border is identified by visualizing and palpating the rotator interval. The subscapularis is incised 1 cm medial to its insertion onto the lesser tuberosity in its tendinous portion (Fig. 3). This
Figure 2 The anterior-lateral leading edge of the coracoacromial ligament (clamped) is resected for improved superior exposure.
64
M.J. Bahu et al
Figure 3 The subscapularis is incised approximately 1 cm medial to its insertion, leaving a cuff of tissue laterally (arrow) for subsequent repair.
Figure 5 By using blunt dissection, the confluent superior portion of the subscapularis can be teased from the anterior capsule using the inferior split to identify the correct plane of dissection.
will ensure tendon to tendon apposition for later repair. Next, the subscapularis is separated from the underlying glenohumeral capsule. This is the most important and demanding step of the procedure. The upper portion of the subscapularis is confluent with the capsule, but, inferiorly, the capsule and subscapularis muscle are typically separate entities14 (Fig. 4). Blunt dissection at the inferior aspect of the subscapularis allows identification of the plane between the two structures. Once the plane is defined, an elevator and Mayo scissors are used to tease the confluent portion of the subscapularis off the anterior capsule (Figs. 5 and 6). Tag sutures are placed to keep traction on the subscapularis tendon during separation. The axillary nerve should be protected during subscapularis release. The “tug test”15 may be helpful in identifying the nerve. Adducting and externally
rotating the humerus helps to move the axillary nerve further from the operative dissection. Once the subscapularis is completely released, the capsule is incised approximately 0.5 cm medial to the subscapularis stump, leaving an adequate cuff of capsular tissue for subsequent repair (Fig. 7). The capsular incision begins superiorly at the rotator interval and continues inferiorly with traction sutures placed in the free edge (Fig. 8). Once the neck of the humerus is reached, the arm is externally rotated and the capsule released off the neck with a scalpel. The amount of capsule released at the inferior neck is determined by the degree of capsular redundancy. The surgeon places a finger in the inferior pouch and pulls on the tag sutures. If the pouch is obliterated and the finger is completely pushed out of the pouch with tension on the tag sutures, then an adequate amount of capsule has been released. It is important to recognize that the inferior capsule splits into two layers and has a dual attachment to the inferior humeral neck (Fig. 9). To perform an adequate shift, the inner and outer layers must be released from the neck of the
Figure 4 Inferiorly, the subscapularis muscle is not adherent to the capsule and the two structures can be more easily separated. The dotted arrow points to the confluent subscapularis tendon and anterior capsule superiorly. The dashed arrow points to the plane developed inferiorly between the two. The solid arrow points to the subscapularis muscle undersurface.
Figure 6 Mayo scissors can then be used to complete the separation.
Open instability repair
Figure 7 The capsule is sharply incised, taking care not to damage the humeral head cartilage below. An adequate cuff of tissue is left behind for subsequent repair.
65
Figure 9 Dual attachment of the inferior capsule on the humeral neck (arrows).
humerus to prevent capsular tethering14 (Fig. 10). After both layers are released, the inferior redundant pouch is obliterated with superior traction. At this point, the external surface of the capsule is inspected and residual attachments of the subscapularis are removed. Often these attachments lie far medially and can prevent complete shifting if left intact. A Fukuda retractor is placed into the glenohumeral joint, and the humerus is moved posteriorly to allow visualization of the glenoid and labrum. If a Bankart lesion is identified, it is managed at this time. The anterior-inferior glenoid rim lesion is prepared with a curette to bleeding bone. Suture anchors are placed at the articular cartilage/scapular neck margin. Care is taken to avoid placing these suture anchors on the medial glenoid neck. Depending on the size of the lesion, multiple anchors are needed, and the typical number is three. The sutures are passed through the capsule from inside to outside and then tied. If there is excessive medial capsular redundancy or the anterior inferior labrum has been attenuated, an anterior crimping (barrel) stitch is placed. The
stitch is started on the external side of the capsule at the capsule-labral junction. It is passed through the capsule and then back out the capsule in a mattress fashion (Fig. 11). Once tied, the anterior-medial redundancy is obliterated, and a bolster to the anterior labrum is created (Fig. 12). The labrum is palpated to appreciate the recreated labral bumper. As mentioned previously, one of the advantages of a humeral-based shift is the ability to titrate the amount of capsular shift to the pathology identified intraoperatively. For patients with isolated anterior instability, only the anterior capsule is mobilized. However, patients with bidirectional (anterior and inferior) instability have a large inferior pouch that needs to be reduced. In these cases, the anterior capsule is split horizontally between the inferior and middle glenohumeral ligaments and overlapped in a pants-over-vest fashion to further reduce volume. The arm is positioned to 20° or 30° of abduction and 20° or 30° of external rotation during capsular reattachment. More abduction and external rotation are used in overhead athletes. Less abduction and external rotation are used in pa-
Figure 8 The capsular incision is continued inferiorly by using tag stitches on the released anterior capsule to apply traction.
Figure 10 Release of the dual inferior capsular attachment, allowing a complete shift of the capsule.
M.J. Bahu et al
66
Figure 11 An anterior crimping (barrel) stitch is used to decrease the redundancy of the anterior-inferior capsule. This is a mattress suture started on the superficial side of the capsule. Figure 13 The anterior-inferior capsule is advanced superiorly and reattached to the capsular sleeve preserved on the humeral neck.
tients with large Hill-Sachs lesions or anterior glenoid bone deficiency. The inferior aspect of the capsule is held under mild tension with tag sutures, advanced superiorly (thus, the capsular shift), and reattached in its new position with simple sutures (Fig. 13). If the horizontal “T” has been made, then the horizontal limb is repaired in a pants-over-vest fashion after the inferior portion is secured. The superior portion of the capsule is repaired last. The rotator interval is repaired if the preoperative sulcus sign remained positive in external rotation. The surgeon must be aware of overtightening the capsule. This will limit external rotation, particularly in overhead-throwing athletes. The subscapularis is closed anatomically followed by a layered skin closure. Drains are not routinely used. A sling and swathe are applied in the operating room.
Rehabilitation A sling is used postoperatively for 6 weeks to protect the repair. Exercises are initiated within 10 days beginning with pendulums. Range-of-motion limits are determined intraoperatively, but, in general, elevation to 100° and external rotation to 15° are begun from 10 days to 2 weeks. From 2 to 4 weeks, elevation to 140° and external rotation to 30° are allowed. At this time, gentle resistive exercises are initiated. At 4 to 6 weeks, elevation is increased to 165°, external rotation to 40°, and resistive exercises are slightly increased. After 6 weeks, external rotation is increased further, and terminal elevation stretching is permitted. The goals are to achieve full motion over several months and to avoid failure by advancing the rehabilitation too quickly. These patients should have their progression monitored closely, and return to vigorous sports is generally delayed for a minimum of 6 months.
Results
Figure 12 Once tied, the barrel stitch reduces anterior-medial capsular redundancy and an anterior-inferior bolster is created. This can be palpated.
In a study performed at our institution, 68 shoulders in 63 athletic patients with anterior-inferior glenohumeral instability underwent an anterior-inferior capsular shift procedure, including the dominant arm of 31 overhead-throwing athletes. Good or excellent results were achieved in 94% of patients, including 75% returning to their previous level of athletic competition. External rotation loss averaged 7°, and only two patients had recurrence of dislocation.11 In a separate study of patients undergoing capsular shift, 38 patients with medial redundancy who received a crimping “barrel” suture were compared with 40 patients who did not have redundancy. Despite a higher number of dislocations and a longer duration of symptoms preoperatively, the incidence of good and excellent results and postoperative Rowe scores were similar for both groups.12
Open instability repair
Conclusion Our understanding of the pathophysiology of anterior shoulder instability has improved in the past decade. The primary pathology is related to labral detachment, capsular redundancy, and associated loss of tension of the glenohumeral ligaments. When nonoperative intervention has failed, treatment should be directed at restoring the original anatomy. An anatomic reconstruction and early range of motion will yield successful results in patients with anterior shoulder instability. The inferior capsular shift as described by Neer and Foster7 is preferred because the amount of capsule being shifted can easily be titrated to treat the amount and direction of pathology found at surgery. The procedure allows excellent exposure of the glenoid and the ability to individualize the repair. If performed meticulously, the anterior-inferior capsular shift provides excellent enduring results while allowing patients to return to full activity.
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