Anterior Glenohumeral Instability Treatment & Management

Indications and contraindications for surgery

At present, there is no firm consensus on the optimal treatment strategy for first-time glenohumeral dislocation, though early surgical stabilization is increasingly being preferred in view of the high failure rates and decreased cost-effectiveness of nonoperative management alone. ^[47] Nonmodifiable risk factors attributed to a patient must be considered as well.

The indications for surgical repair in a patient with anterior glenohumeral instability depend on the patient presentation and the individual surgeon. A shoulder in which conservative therapy has failed or any shoulder that has been rendered unstable may undergo repair.

Frequently, determination of appropriate treatment may be facilitated by classifying patients into one of the following two categories:

• Young patients with heavy physical demands - These patients may forgo conservative therapy and proceed to immediate surgical repair; this recommendation is based on the high recurrence rate and the patient's desire to return to activity
• Older patients with lesser physical demands - These patients may try conservative therapy before assuming the risks of surgical repair; they have a lower likelihood of recurrence and may not require any treatment beyond conservative therapy

Surgery is also indicated if the patient is symptomatic with activities of daily living (ADLs) or if overhead stability is specifically needed. The patient must understand, however, that overhead stability cannot be guaranteed postoperatively.

Surgical repair is relatively contraindicated in older patients with low physical demands, who have little chance of recurrence. Conservative therapy, including physical therapy to strengthen the rotator cuff, is indicated in preference to exposing these patients to the risks of operation. Patients who have been asymptomatic in their ADLs also need not be exposed to the risks of surgery. These patients are best monitored for any recurrent dislocations.

A contraindication exists in the case of multidirectional instability of the shoulder. In these atraumatic dislocations, patients are able to dislocate and relocate the shoulder voluntarily. Predisposing factors include psychiatric dislocations, laxity due to repetitive injury (as in competitive swimmers), and congenital collagen abnormalities (eg, Ehlers-Danlos syndrome and Marfan disease). The history and physical examination must be used to identify these patients. If these patients are treated as if they have unidirectional dislocations, operative therapy may fail. The amount of inferior capsular redundancy in multidirectional instability requires an operative procedure addressing the possibility of future inferior instability.

There is considerable room for improvement in the management of anterior glenohumeral instability, especially with arthroscopic treatment. Studies have shown that any type of shoulder instability can be treated arthroscopically. Advances in techniques and equipment have made treatment somewhat easier. The rate of recurrence remains higher after arthroscopic treatment than after open repair. Open repairs continue to provide good functional results. Postoperative range of motion (ROM) of the shoulder in patients who undergo open repair may not reach that observed in patients with arthroscopically repaired shoulders.

Once the decision has been made to proceed operatively, the next major question is the choice of procedure. Major considerations include patient profile and the amount of glenohumeral bone loss. Balg and Boileau developed a scoring system, the Instability Severity Index, to determine the likelihood of arthroscopic surgical failure. ^[48] They associated scores higher than 6 with a high risk of failure; however, subsequent studies have suggested that the threshold for failure may be much lower (ie, >2). ^[49]

Traditional recommendations have proposed arthroscopic repair for glenolabral injuries with less than 20% bone loss and procedures with anterior glenoid bony augmentation for cases where bone loss exceeds 20-25%. ^[8] However, this threshold may be lowered to 15% on the basis of more recent literature.

Additionally, if a patient has a Hill-Sachs lesion that is considered on track, it can be left alone and managed as above. If it is instead considered off track with a subcritical bony defect, it should be managed with arthroscopic Bankart repair and remplissage (filling in). If it is off track with glenoid bone loss greater than 15-20%, it should be managed with a Latarjet procedure or anterior glenoid bone block reconstruction. Multicenter randomized controlled trials have been initiated with the aim of investigating management of patients who fall in the middle of that spectrum.

Nonoperative management of anterior glenohumeral instability must be considered. This consists of a period of shoulder immobilization. Subsequent physical therapy reestablishes ROM and strengthens the rotator cuff. As discussed above, age and other nonmodifiable risk factors are important to consider.

More important, it seems, is the physical therapy program. This should focus on isotonic strengthening before isokinetic strengthening. The first musculature to rehabilitate consists of the periscapular muscles: the serratus anterior, the trapezius, and the rhomboids. The deltoids follow, and finally, strengthening should focus on the rotator cuff.

No substantial evidence supports physical therapy as a treatment for high-risk patients. Thus, conservative management is reserved for persons with first-time dislocations who are older than 20-25 years and are sedentary.

Indications for repairing an anteriorly unstable shoulder are not obvious. The patient and surgeon must consider the possible outcomes in the light of the patient's activity level and the most probable natural history of the individual's instability. At times, forgoing conservative therapy and proceeding directly to surgical repair may be appropriate.

In the case of a patient who has experienced dislocation fewer than three times, attempting an arthroscopic repair is reasonable. Arthroscopic repair is associated with a lower incidence of shoulder stiffness but has been shown to have a higher risk of recurrence.

Persons with truly recurrent dislocations have dislocated their shoulder more than two or three times. In these cases, patients may want to risk the possibility of stiffness in return for the stability created by a Bankart repair.

Many options exist for the surgical repair of anterior glenohumeral instability. Arthroscopy provides the least invasive repair. Open shoulder repairs include the Putti-Platt, Bristow (or Bristow-Latarjet), Magnuson-Stack, inferior capsular shift, Eden-Hybbinette, Trillat, and Bankart procedures. ^[50]  Arthroscopic repair has potential advantages, including improved cosmesis, less postoperative pain, shorter operating time, decreased blood loss, better preservation of external rotation, and avoidance of subscapularis-related complications. ^{[51, 52]}  Arthroscopic Bankart repair is the most commonly used technique for treatment of athletes with anterior shoulder instability. ^[8]

One study, reviewing data from the American Board of Orthopaedic Surgery (ABOS), noted that the use of open repair has been declining and that there has been a trend toward arthroscopic Bankart repair. ^[53]  This study found the most common complications to be nerve palsy/injury and recurrent dislocation. The rate of nerve injury was 2.2% in the open group, compared with 0.3% in the arthroscopic group; the dislocation rate was 1.2% with open stabilization, compared with 0.4% arthroscopically.

Intraoperatively, arthroscopy provides better visualization of the joint. Although recurrence rates in persons with first-time dislocations have been reported to be as low as 5%, subsequent literature has suggested recurrence rates rivaling those noted with open Bankart repairs. In addition, the operative procedure does require significant training.

In a retrospective cohort study that included 364 shoulders), Gerber et al investigated long-term (≥6 y) outcomes of arthroscopic Bankart repair versus open Latarjet repair for recurrent anterior shoulder instability. ^[54] Arthroscopic Bankart repair was found to be inferior, with 41.7% recurrence of instability or apprehension post Bankart, compared with only 11% post Latarjet. ^[54]  Secondary outcome measures (patient satisfaction, survivorship, and operative revision) similarly favored the Latarjet procedure, and the difference increased significantly in parallel with increased follow-up time.

Proper patient selection has led to good outcomes in arthroscopically repaired shoulders. ^[55]  Good candidates for arthroscopic repair are patients with the following:

• Discrete Bankart lesion
• Well-developed inferior glenohumeral ligament (IGHL)
• No significant capsular laxity
• No intraligamentous injury
• No concomitant intra-articular pathology
• Unidirectional instability

Patients who require open repair are those with the following:

• Bone loss
• Capsular laxity
• Poor tissue quality

Preparation for surgery

Several concerns are important preoperatively. The most significant of these is that anterior shoulder instability must be confirmed. The shoulder should be examined again after anesthesia is induced. If the shoulder is found to have multidirectional instability, the operative plan should be canceled or revised.

Operative details

Arthroscopic Bankart procedure

Arthroscopic repair may be either intra- or extra-articular. Extra-articular repair is indicated primarily for labral tears; damage that is more extensive requires an intra-articular repair.

The arthroscopic repair can be performed with the patient in either the lateral recumbent position or the beach-chair position. It should be kept in mind that the lateral position has been associated with traction neurapraxia and allows less joint motion. Recurrent rates may be less with lateral position. ^[56] The beach-chair position is convenient if a conversion to an open repair is anticipated.

There are several keys to a successful arthroscopic Bankart repair, including the following:

• Appropriate patient selection
• Proper mobilization of capsulolabral tissues
• Repair of the tissue to the edge of the articular surface (not the glenoid neck)
• Identification and treatment of capsulolabral injury

Preoperative radiography helps determine the presence of a bony Bankart lesion.

The arthroscopic procedure for a soft Bankart lesion also starts with examination under anesthesia. The patient may be in the lateral recumbent or beach-chair position. Access to the joint starts with a posterolateral glenohumeral portal for viewing the joint. A thorough examination is performed before an anterior working portal is made lateral to the coracoid.

The edge of the glenoid articular cartilage is abraded. The capsulolabral complex is dissected and then grasped and advanced over the abraded bone. Anterior reconstruction is then performed with suture anchors and plication of the loose anterior capsule into the labral repair. ^{[57, 58]} The most inferior suture is placed first, allowing superior sutures to further tighten the capsuloligamentous complex. The sutures are tightened with the shoulder in internal rotation. ROM can be examined intra-articularly, and the incisions are closed.

Bone graft augmentation may be a beneficial adjunct to arthroscopic Bankart repair in patients who have recurrent anterior shoulder instability with glenoid bone loss. ^[59]

Open Bankart procedure

Although the procedure has evolved through the years, the open Bankart repair has remained essentially unchanged from the original description by Rowe in 1978.

First, the patient's shoulder is examined under anesthesia to ensure that the patient truly has purely anterior instability and thus can benefit from a Bankart repair. An incision is made from the coracoid process inferiorly to the axilla. The deltopectoral groove is dissected, exposing the cephalic vein and retracting it. The coracoid process is osteotomized, allowing the coracobrachialis and short head of the biceps to retract inferiorly.

External rotation of the arm exposes the subscapularis. The circumflex vessels at the inferior border of the muscle can be ligated. The subscapularis is then separated from the capsule. With the arm fully externally rotated, a vertical incision is made in the subscapularis just lateral to the glenoid rim. This provides a large flap for repair of the capsule with adequate external rotation postoperatively.

With the humeral head retracted posterolaterally, the rim of the glenoid and the anterior neck of the scapula are freshened by using a small osteotome. Three holes are made in the anterior glenoid rim, located at 1, 3, and 5 o'clock on the right glenoid and at 11, 9, and 7 o'clock on the left glenoid.

A double-0 suture is passed through each hole and then through the edge of the lateral capsular flap. This is tied while the capsular flap is held to the freshened anterior glenoid rim. With the same suture ends, the medial capsular flap is then tied down on top of the lateral one. This reinforces the capsule at the rim of the glenoid. External rotation is then checked; it should extend easily to 25-30° beyond neutral.

Closure is achieved by returning the tissues to their anatomic positions. The subscapularis is sutured to the lesser tuberosity and secured. Thus, the muscle is not shortened, overlapped, or transplanted, as is the case in other techniques. The coracoid is anchored in place with 0 suture at its base. No separation of the coracoid has been described with the use of suture to anchor it.

Arthroscopic Latarjet procedure

The arthroscopic Latarjet procedure appears to be an effective means of treating off-track Hill-Sachs lesions, restoring them to an on-track state. In a study by Plath et al, a mean persisting enlargement of the glenoid arc of 14% beyond native dimensions remained at a mean of 23 months after this procedure. ^[60]

Ranne et al reported a modification of the arthroscopic Latarjet procedure for treating anterior glenohumeral instability, in which the detached coracoid was exteriorized through the anteroinferior portal for drilling and shaping. ^[61]  The 10 patients with severe anterior glenohumeral instability who were treated with this technique had only mild-to-moderate postoperative pain, with no postoperative infections or recurrent dislocations. In terms of safety, the operation was found to be comparable to other operations on the coracoid process in the proximity of the brachial plexus.

A retrospective cohort study by Ali et al found the clinical and radiographic outcomes of the arthroscopic Latarjet procedure to be similar to those of the equivalent open procedure. ^[62]

Open Latarjet procedure

The open Latarjet procedure is being increasingly utilized as a solution to anterior glenohumeral instability due to significant glenoid bone deficiencies greater than 21%, for which the failure rate of arthroscopic Bankart repair increases significantly. ^{[63, 64, 65]} This technique involves splitting the subscapularis to attach a parallel-positioned coracoid process onto the exposed glenoid by using two 3.5- to 4.5-mm screws, as described by Edwards and Walch. ^[66]

The open Latarjet procedure is reported to prevent recurrent instability in 99% of correctly selected patients. ^[67]  However, there are several drawbacks to the procedure that may result in complications, such as postoperative stiffness and increased loss of motion. There is also an increased concern for nerve injury.

Reduction of complications

There are several intraoperative details that a surgeon should be aware of to reduce the risk of postoperative complications. For example, incorrect positioning of the coracoid process may result in a lateral overhang, which can lead to rapid bone degenerative joint disease. ^[68]  Additionally, overtightening of the screws may cause coracoid fractures; this can be prevented by tightening the screws with the two-finger technique. Complications and postoperative rehabilitation can be minimized by employing proper surgical technique. 

Postoperatively, the shoulder is kept in an arm sling for 3-4 weeks. The shoulder may be internally rotated and flexed for hygiene maintenance, but external rotation is prohibited.

After 4 weeks, full active flexion is encouraged and assisted with physical therapy. At 6 weeks, internal and external rotation of the shoulder is begun by using 5-lb (~2.25-kg) and 10-lb (~4.5-kg) weights. At 3 months, full and unrestricted weightlifting is allowed. Competitive throwers should be restricted from unrestricted athletics for 6 months.

At 3 months, the patient should have regained 70% of external rotation and elevation of the shoulder. At 6 months, 75-100% of normal motion and strength may be observed.

Successful repair of anterior glenohumeral instability is extremely rewarding and can render a patient fully functional within months. However, as in any surgical procedure, complications are possible. Unsuccessful surgery in this case can be difficult to salvage.

The most commonly reported complication of open Bankart repair is persistent instability. ^[63]  Reported rates of recurrent instability range from 3% to 50%. The cause of failure should be determined.

The most common adverse effect of anterior instability is loss of motion. Frequently, decreased external rotation of the humerus is desired to prevent recurrent dislocation; thus, the loss of motion is not reported as a complication. Complications of decreasing the normal shoulder ROM can be serious. In athletes, the late cocking position is disabled, thus decreasing the velocity of their throw. More extensive reductions in external rotation can cause posterior translation of the humeral head.

Iordens and Lieshout found that Putti-Platt repairs in 51 patients resulted in tight anterior structures, which led to glenohumeral arthritis. ^[69]  This procedure is not the only repair that may result in tight anterior structures: The classic Bankart repair has also been shown to cause limitation of motion and, thus, clinical and radiographic arthritic changes. How much limitation in motion is required to cause late degenerative arthrosis remains to be determined. Studies to date have suggested that small limitations do not cause significant degeneration.

Excessively tight anterior capsules must be addressed to prevent premature arthritic changes. The subscapularis can be released and sutured back into place with the arm externally rotated to the desired position. For greater restrictions, requiring more than 20° of correction, the subscapularis is dissected in the coronal plane, creating a superficial and deep layer. The medial edge of the deep layer of the subscapularis can be sutured to the lateral edge of the superficial layer.

An incorrect diagnosis prior to surgery undoubtedly leads to failure. This can occur when atraumatic multidirectional shoulder instability is confused with traumatic unidirectional anterior instability. In the case of the former, an inferior capsular shift is in order, whereas for the latter, an open or arthroscopic Bankart repair is indicated.

Voluntary instability is a contraindication for any surgical repair mentioned above. These patients can dislocate their shoulders using muscular contractions or arm positioning. A study by Rowe found that most people who dislocate their shoulders voluntarily have "significant psychiatric histories." Nonoperative treatment is necessary in these patients.

Nonanatomic repairs have been shown to result in higher postoperative instability rates. In the original Bankart repair, the anterior glenoid is essentially reconstructed to its original anatomic shape. Procedures that fail to reconstruct the anterior glenoid have been shown to fail more frequently.

Bony Bankart lesions, if large enough, leave a glenoid fossa that lacks concavity. Defects involving greater than 20% of the articular surface must be addressed. Bony lesions involving less than 20% of the glenoid can be resected with the capsulolabral mechanism reattached to the remaining anterior glenoid.

One study assessed the factors associated with the presence, size, and type of glenoid bone defect in patients with anterior shoulder instability. ^[66]  Computed tomography (CT) revealed a glenoid bone defect in 72% of the 161 patients. The defect was significantly associated with recurrent dislocation, increasing number of dislocations, timing from first dislocation, and manual work; a critical defect was associated with number of dislocations and age at first location; and bony Bankart lesion was associated with male sex and age at first location.

Osteochondral defects of the humeral head may predispose a shoulder to continued instability. A Hill-Sachs lesion alone infrequently causes instability, but when it is coupled with a Bankart lesion, it creates an easily subluxable or dislocated shoulder. Preoperative CT of the Hill-Sachs lesion helps determine the need for repair. The humeral lesion can be prevented from perching on the anterior glenoid by imbricating the anterior capsule and thereby decreasing external rotation.

Other methods of filling in a Hill-Sachs defect have been described, including transfer of the infraspinatus with a portion of greater tuberosity, humeral osteotomy, and humeral hemiarthroplasty or osteochondral allograft for defects involving more than 40% of the head's articular surface. ^{[70, 71]}

Further treatment using so-called remplissage, or filling in, of the Hill-Sachs lesion defect with rotator cuff tendon has been studied. A study by Nourissat et al found no significant statistical difference in ROM between patients treated with arthroscopic Bankart repair alone and those treated with Bankart repair and remplissage. ^[72]  The recurrence rates were identical in the two groups, and one third of patients experienced posterosuperior pain.

Another cause of surgical failure is rupture of the subscapularis. Patients may present after a traumatic event or with persistent postoperative pain, weakness, or continued instability. Physical examination reveals increased external rotation and positive liftoff test results. Magnetic resonance imaging (MRI) may be helpful in confirming this complication. Operative repair includes mobilization of the tendon, which frequently retracts underneath the conjoined, and reattachment to its insertion.

Hardware placed in or around the glenohumeral joint can always cause complications. Loosening and resulting failure have been shown to occur at any time point after surgery. Zuckerman found that the most common culprits were screws or staples that were placed for a coracoid transfer or anterior capsular plication; most of these failures necessitate reoperation. ^[73]  Chondral damage was found in 41% in Zuckerman's report.

Follow-up care can be scheduled on an annual basis after patients have returned to full activity and strength. At these visits, any symptoms of subluxation or dislocation should be explored. Shoulder ROM, strength, and stability are examined, and a radiographic examination is also performed.