Open repair for anterior shoulder instability

OVERVIEW

Chapter synopsis

While arthroscopic shoulder stabilization techniques have become increasingly popular, their popularity is tempered by high failure rates in high-risk groups. Open capsular repair is an often-neglected technique for patients at risk for postoperative instability with success rates comparable to bony augmentation procedures and a low complication rate.

Important points

Open capsular repair continues to have an important place in the armamentarium of the shoulder surgeon.
The results of open stabilization have been uniformly excellent with postoperative recurrence rates generally reported between 0% and 5%.

Clinical/surgical pearls

1.
For optimal cosmesis, mark the skin incision in the preop holding area by having the patient internally rotate the shoulder. Identify the skin crease in extending from the axilla to a point inferior and 1-2 cm lateral to the coracoid. Use this crease for your incision.
2.
Use 2 self-retaining retractors to free your assistants. We prefer the Kolbel self-retaining shoulder retractor with detachable blades (Link America, Waldermar Link, Hamburg, Germany). We use the retractors so that the convex side faces the wound. Blades of an appropriate depth are then attached. The first retractor is used to spread the wound from medial to lateral. We place the second retractor so that its base enters from the medial side to spread the wound from inferior to superior. Generally, a deeper blade is placed inferiorly then superiorly.
3.
Monitor arm position when tensioning the capsule. Remind the assistant to keep the arm at the 45/45 position for a standard repair.
4.
Confirm that the assistant has the humeral head reduced in the glenoid when tying your capsular sutures. If the shoulder is not reduced, the capsule will not oppose the glenoid neck.
5.
Be meticulous in closing the subscapularis. Consider use of modified Kessler or Mason-Allen sutures for added strength.

Clinical/surgical pitfalls

1.
Dissect medial to the cephalic vein when developing the deltopectoral interval since branches to the vein enter laterally.
2.
Avoid overzealous retraction on the conjoined tendon, which attaches to the coracoid, to avoid injuring the musculocutaneous nerve.
3.
Make sure that the subscapularis is not tenotomized too far laterally. If you go too far lateral, there will not be a stump to sew back to the tendon at closure.
4.
Externally rotate the shoulder as you take down the inferior aspect of the subscapularis to protect the axillary nerve. Expect to encounter branches of the anterior humeral circumflex artery in this area and be prepared to ligate or coagulate them.

Video available

Open Repair of Anterior Shoulder Instability

Introduction

Open stabilization techniques have had a storied history of effectiveness in reducing anterior shoulder instability. These procedures have generally yielded excellent outcomes with postoperative recurrence rates between 0% and 5% in unselected populations. Due to the emergence of arthroscopic methods of stabilization, recently-trained orthopedic surgeons are infrequently tutored on this reliable technique. Unfortunately, arthroscopic repairs have been plagued by unacceptably high recurrence rates in high-risk groups (contact athletes, patients with capsular laxity, and those with bone loss of the humeral head, or glenoid fossa). In fact, Balg and Boileau devised the “Instability Severity Index Score” in which they recommended that arthroscopic methods of stabilization be avoided in most high-risk patients. Such at-risk patients are now commonly treated with a bone-augmentation technique such as the Latarjet procedure. In our opinion, this paradigm is essentially jumping from “point A to point C.” It disregards “point B”—open capsular repair.

Pre-operative considerations

History

The diagnosis of an anterior shoulder dislocation is usually straightforward. The patient experiences a traumatic injury and feels the shoulder “pop out.” The incident usually occurs when the arm is positioned in abduction and external rotation. Manipulative reduction of the joint is often necessary. Such patients usually develop a Bankart lesion with detachment of the anteroinferior labrum leading to insufficiency and elongation of the inferior glenohumeral ligament complex.

In some cases, however, dislocation can occur with no history of significant trauma. These latter patients, who have generalized ligamentous laxity and a component of multidirectional instability, are less likely to demonstrate a Bankart lesion. Instead such patients typically have enlargement of the rotator interval and a loose and patulous capsule.

The diagnosis of anterior subluxation may be more subtle. The chief complaint may be a sense of movement or clicking with certain activities. Pain, rather than instability, may be the predominant complaint.

Physical examination

Apprehension tests are designed to induce anxiety and protective muscular contraction as the shoulder is brought into a position of instability. The anterior apprehension test is performed with the arm abducted and externally rotated. As the examiner progressively increases the degree of external rotation, the patient develops apprehension that the shoulder will “slip out.” This test is uniformly positive in patients with anterior instability.

During the relocation test, the examiner’s hand is placed over the anterior shoulder of the supine patient. A posteriorly directed force is applied with the hand to prevent anterior translation of the humeral head. The shoulder is then abducted and externally rotated as it is in the apprehension test. A positive result is obtained when this anterior pressure allows increased external rotation and diminishes associated pain and apprehension. The relocation test seems to be more reliable in overhead athletes and may not be positive in all cases of anterior instability.

The belly press and lift-off tests should also be performed to confirm the integrity of the subscapularis tendon.

Imaging

Routine radiographic examination of the unstable shoulder includes an anteroposterior (AP) view (deviated 30 to 45 degrees from the sagittal plane in order to parallel the glenohumeral joint), a trans-scapular (Y) view, and an axillary view. West Point and Stryker Notch views are helpful in demonstrating bony lesions of the humeral head and glenoid.

Magnetic resonance imaging (MRI) is useful to determine if a Bankart lesion is present and also to assess patients for evidence of concomitant rotator cuff or labral pathology in other segments of the shoulder. The accuracy of MRI in determining labral pathology is, in our experience, increased with arthrography. Because of the possibility of concomitant rotator cuff injury, MRI should always be considered in older patients with instability—especially if strength and motion are slow to recover after a traumatic episode.

Computed tomography (CT) scans may be indicated if bony deficiency is suspected on plain films. However, the surgeon should be cautioned that CT tends to overestimate the size of larger glenoid lesions and that CT measurement of smaller lesions is not superior to arthroscopic measurement.

Rationale for open capsular repair

The results of “modern” techniques for arthroscopic stabilization for anterior shoulder instability have not attained the high rates of success reported for open capsular repair. Recent systematic reviews have shown that the recurrence rates for arthroscopic repair exceed the historical rates for open stabilization. ^, In one such review, Hohmann et al. noted that results reported in the literature for arthroscopic stabilization between 2005 and 2015 have not improved statistically when compared to results reported between 1995 and 2004. Similarly Alkaduhimi et al. concluded that “Despite advances in surgical techniques and devices during the last 20 years...the recurrence rate for arthroscopic shoulder stabilization has only marginally decreased.”

The high failure rates have persisted despite careful patient selection. Many studies of arthroscopic stabilization exclude high-risk groups such as contact athletes, patients with bony defects of the humeral head and glenoid, and those with capsular laxity. The preponderance of highly selected populations in reports after arthroscopic stabilization makes valid comparison with the outcomes of open stabilization without such exclusions being inherently problematic. Additionally, a dearth of case series from experienced shoulder surgeons on the results of open stabilization over the past 20 years does not permit adequate assessment of “modern” open techniques for such comparisons. In this era of evidence-based medicine, however, seven separate meta-analyses have concluded that the results of open stabilization are superior to those of arthroscopic stabilization. ^, ^, ^, As an example, Hohmann et el noted a 37% higher risk of recurrent instability after arthroscopic repair compared to open methods.

Open stabilization has several advantages over arthroscopic repair that may well explain the differences in recurrence rates: (1) Open methods allow the surgeon to free the capsule from the subscapularis tendon so that the capsule may be precisely tensioned without adherence to the subscapularis. (2) The rotator interval is better visualized and tensioned via an open technique. Open rotator interval closure does not have the same effect on shoulder translation or rotation as arthroscopic closure. (3) The capsule can be doubled by overlapping the capsule during open repair. (4) The arm can be optimally positioned for open repair. (5) Open techniques confer the ability to tie knots extra-articularly, eliminating concern about suture impingement on the articular surfaces of the shoulder.

Indications

The indications for surgical treatment of recurrent anterior shoulder instability are generally subjective. They include the patient’s desire to avoid the pain and morbidity of instability (including the necessity of reporting to the emergency room to have the shoulder reduced), recurrent pain, an inability to perform certain activities because of apprehension regarding the shoulder, and the desire to improve athletic performance. Failure of a thorough trial of nonoperative treatment is also an indication for surgical treatment.

Indications for open stabilization over arthroscopic stabilization include (1) participation in a contact or collision sport, (2) male instability patients under the age of 20, (3) small to moderate bony defects of the humeral head or glenoid, (4) humeral avulsion of the glenohumeral ligaments, (5) failed arthroscopic repair, and (6) atraumatic instability. Essentially all patients with an Instability Severity Index Score > 6 (in which arthroscopic methods have a reported failure rate of 70%) (reference #5) are candidates for open capsular repair. In our practice, such patients represent approximately 80% of those who require surgical treatment for anterior instability. We will consider two high-risk groups below:

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