Shoulder Instability Repairs

Marc S. Haro, MD, MSPT

Todd R. Hooks, PT, ATC

Kevin E. Wilk, DPT, FAPTA

Lucy Oliver-Welsh, MBChB

Brian J. Cole, MD, MBA

Dr. Cole or an immediate family member has received royalties from Arthrex, DJ Orthopaedics, and Elsevier Publishing; serves as a paid consultant to Arthrex, Regentis, and Zimmer; has stock or stock options held in Carticept and Regentis; has received research or institutional support from Aesculap/B.Braun, Arthrex, Cytori, Medipost, National Institutes of Health (NIAMS and NICHD), and Zimmer; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research–related funding (such as paid travel) from Athletico, Ossur, Saunders/Mosby-Elsevier, SLACK Incorporated, Smith & Nephew, and Tornier; and serves as a board member, owner, officer, or committee member of the American Journal of Orthopedics, the American Orthopaedic Society for Sports Medicine, the American Shoulder and Elbow Surgeons, the journal Arthroscopy, the Arthroscopy Association of North America, the International Cartilage Repair Society, the Journal of Bone and Joint Surgery–American, the Journal of Shoulder and Elbow Surgery, and the Journal of the American Academy of Orthopaedic Surgeons. Dr. Wilk or an immediate family member serves as a paid consultant to LiteCure Laser Company Intelliskin Zetroz and Performance Health; serves as an unpaid consultant to AlterG; has received research or institutional support from Intelliskin; and has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research–related funding (such as paid travel) from Churchill Livingstone CV, Mosby Slack Publishing, and Dynasplint Bauerfeind ERMI Device. Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Haro and Dr. Hooks.

Introduction

Shoulder instability is common in young individuals. Whether it is a relatively straightforward acute anterior traumatic dislocation, posterior instability, or a more subtle multidirectional instability, it is important to ascertain the type of shoulder instability in order to correctly guide treatment. Shoulder instability can be unidirectional or multidirectional, as well as both traumatic and atraumatic in nature. The classical acronyms TUBS (Traumatic Unidirectional Bankart Surgery) and AMBRI (Atraumatic Multidirectional Bilateral Rehabilitation Inferior capsular shift) have long been used to help the clinician guide treatment based on the type of instability. While these simple acronyms have been used for years and may not cover all types of shoulder instability, they are still helpful in drawing attention to the mechanism of instability and the nature of treatment often recommended.

When evaluating a patient with possible shoulder instability, several critical factors must be assessed. First is the patient’s age. Younger individuals with anterior shoulder dislocations are at a significantly higher risk to have recurrent instability compared to older individuals. Among 15 to 35 year olds, about 50% will have a subsequent instability in the first 2 years following primary dislocation, and about two-thirds within 5 years. Due to the high recurrence rate, and the significant impact that shoulder instability can have on an individual, surgical stabilization is often recommended to treat young active patients. In contrast, older patients are much less likely to have recurrent instability, and those over age 40 years are far more likely to sustain a rotator cuff injury at the time of an initial anterior dislocation.

Most unidirectional shoulder instability is anterior and traumatic. Anterior instability usually manifests as a dislocation event and often requires a closed reduction. Typically, the mechanism of injury is an abduction and external rotation (ER) force on the arm. The anterior inferior glenohumeral ligaments (AIGHL) and the posterior inferior glenohumeral ligaments (PIGHL) are the primary restraints to anteroposterior translation with the arm abducted. The Bankart lesion, considered the “essential” lesion, is an avulsion injury of the anterior labrum that typically extends from the 2 o’clock position to the 6 o’clock position (in a right shoulder) (Figure 5.1) and disrupts the AIGHLs and has variable healing. There are several varieties of anterior labral injuries, including glenoid labral articular defect (GLAD) lesions and anterior labral periosteal sleeve avulsion (ALPSA) lesions. If these lesions are not treated surgically, patients may suffer from recurrent instability. Anterior glenohumeral instability without labral injury and atraumatic anterior instability is relatively uncommon.

Several other lesions are also associated with acute shoulder dislocation, including humeral avulsions of the glenohumeral ligament (HAGL) lesions and glenoid rim fractures. Also seen,
especially after repeated anterior shoulder dislocation, are Hill Sachs lesions, or osteochondral impaction injuries to the posterosuperior humeral head. These are caused by impaction of the posterosuperior humeral head on the anterior glenoid rim with a dislocation event. Recurrent glenohumeral instability often leads to glenoid bone loss and can affect the decision regarding the surgical technique and the outcome of repair (Figure 5.2).

Figure 5.1 Arthroscopic image of a Bankart lesion (yellow arrow).

Traumatic posterior instability is much less common, involving the posterior labrum and PIGHLs and a reverse Bankart lesion. Posterior instability can be either traumatic dislocation or atraumatic repetitive microtrauma to the posterior capsule and labrum. Traumatic posterior instability is often seen with a posterior directed force on a shoulder that is flexed, adducted, and internally rotated, or it may be associated with a seizure or electric shock when a forceful tetanic muscle contracture causes the stronger posterior shoulder muscle to dislocate the humeral head posteriorly. Atraumatic posterior instability is more common; it is seen in individuals who perform activities with repetitive posterior-directed forces, such as football offensive linemen, weight lifters, and overhead athletes.

Figure 5.2 Arthroscopic image showing anteroinferior glenoid bone loss (yellow arrow).

Multidirectional instability (MDI) is typically defined as instability in two or more directions. While MDI is generally thought of as being atraumatic in nature, and associated with repetitive microtrauma or congenital laxity, it can also be due to extensive labral tears. Those with MDI coupled with large labral tears are probably an extension of traumatic unilateral instability. Patients with atraumatic MDI usually complain of pain or subjective instability with particular activities or arm positions. Often, MDI is seen in overhead athletes, especially those who participate in swimming, volleyball, and gymnastics. They may have associated hyperlaxity and collagen disorders, such as Marfan’s disease and Ehler’s Danlos. These associated collagen disorders decrease the likelihood of a successful surgical outcome.

Preoperative Evaluation

A thorough history and physical examination should be performed to ascertain the nature of the instability. Both shoulders are examined to assess range of motion (ROM), strength, direction of shoulder instability, as well as signs of generalized ligamentous laxity.

Plain radiographs, including true anteroposterior, axillary lateral, and West Point views, should be obtained to evaluate for humeral and glenoid bone loss. A computed tomography (CT) scan with three-dimensional reconstructions should be considered for any patient who demonstrates instability at low angles of abduction, planned revision surgery, or presence of bone loss on plain radiographs. Bone loss greater than 20% may result in failed isolated arthroscopic soft-tissue repair (Figure 5.3). An MR arthrogram is commonly used to assess for the extent of capsulolabral injury, a HAGL lesion, rotator cuff integrity, or posterior pathology.

Surgical Management

When patients have failed conservative measures and continue to have pain and recurrent instability, surgical intervention is often warranted. The nature of the surgery is dependent on the patient’s age, mechanism of injury, and type of instability present. Regardless of the surgical procedure, the patient must be mentally prepared for the surgery, which frequently requires a long rehabilitation period.

Unidirectional Anterior Glenohumeral Instability

The goal of surgical intervention is to restore the attachment of the labrum and AIGHL. Open repair was traditionally achieved with the Bankart procedure. While these procedures are very effective, over the past 10 to 20 years, the advances in shoulder arthroscopy have allowed us to perform these
procedures minimally invasively with comparable results. Additionally, arthroscopic repairs have advantages over open surgery, including lower complication rates (fewer infections and nerve injuries) as well as avoiding surgical disruption of the subscapularis anteriorly and the infraspinatus posteriorly.

Figure 5.3 A three-dimensional CT scan showing significant posterior bone loss after 2 failed posterior instability repairs (yellow arrow).

Arthroscopic Repair

The patient can be placed in a beach chair or lateral decubitus position depending on the surgeon’s preference. Our preference is to perform all instability procedures in the lateral decubitus position. Accurate portal placement is the key to visualization, tissue mobilization, and accurate hardware placement. A standard posterior viewing portal is placed 1 cm medial and 2 cm inferior to the posterolateral acromion. A standard anterior midglenoid (AMG) portal low in the rotator interval, just above the subscapularis tendon, is also established and used for suture management and the easy passage of arthroscopic tools. A posteroinferior (PI) portal, or a 7 o’clock portal (left shoulder), can be placed 3 cm distal and 1 cm lateral to the posterolateral acromion. It gives excellent access to the inferior glenoid and is useful for glenoid preparation, posterior anchor placement, and suture management. The portal also provides access to the posterior glenoid should the lesion extend more posteriorly. Other commonly used portals include an anterior superior portal through the rotator interval and an accessory lateral (Wilmington) portal 1 cm lateral to the acromion.

A standard diagnostic arthroscopy is performed to evaluate the labrum, rotator cuff, and biceps tendon. The humeral head is evaluated for the presence and size of a Hill Sachs lesion (Figure 5.4). Specific attention must be paid to the integrity of the labrum to evaluate for any sign of a Bankart lesion or associated fracture. Glenoid bone loss is assessed, as this may alter the surgical procedure. An ALPSA is found when the disrupted labroligamentous heals medially along the glenoid. This lesion is often found in recurrent dislocators and can be best seen from the anterior superior viewing portal. Special attention is also paid to the anterior capsule to evaluate for the presence of a HAGL. Visualization of the subscapularis muscle fibers through the capsule suggests the presence of this lesion. The arthroscope should also be placed through the anterior portal to fully evaluate the posterior structures. Failure to recognize and address all associated pathology will likely result in an unsatisfactory outcome.

Figure 5.4 Arthroscopic image of a Hill Sachs lesion of the humeral head (yellow arrow).

Once a thorough diagnostic arthroscopy is completed, an arthroscopic elevator is used to develop a plane between the glenoid and capsulolabral complex (Figure 5.5, A) in order to fully release the capsule and labrum so that they can be mobilized onto the glenoid rim (Figure 5.5, B). The glenoid rim is then carefully prepared using an arthroscopic burr or rasp. The bony surface should be decorticated to remove any overlying fibrous tissue and to achieve a bleeding surface, but excessive bone should not be removed.

Once the glenoid rim has been prepared, suture anchors are placed into the glenoid rim to repair the labral tissue back to the glenoid. Regardless of the type of suture anchor used, the key maneuver of the shoulder stabilization procedure is to reestablish the tension of the AIGHL. The most inferior anchor is placed first as a drill guide is introduced into the posterior inferior portal, from which both limbs of the suture pass. The tip of the drill guide is placed between the 5:30 to 6:00 position on the glenoid (right shoulder). This will allow the tissue captured with the suture to be brought anteriorly and superiorly (Figure 5.5, C).

Figure 5.5 Arthroscopic images showing development of a plane between the glenoid and capsulolabral complex. A, The labrum should be thoroughly elevated with an arthroscopic elevator (yellow arrow). B, An adequate release has been achieved when the labrum rests without tension at the level of the glenoid (yellow arrow). C, Illustration of an axial image of an arthroscopic Bankart repair for anterior glenohumeral instability of a right shoulder. D, Illustration of a sagittal image of an arthroscopic Bankart repair for anterior glenohumeral instability of a right shoulder. (C reproduced with permission from Trumble TE, Budoff JE, Cornwall R: Hand, Elbow, & Shoulder: Core Knowledge in Orthopaedics. Philadelphia, PA, Elsevier, 2006.)

We prefer to work from a posterior to anterior direction. In order to restore the disrupted labral tissue back to the glenoid rim and reestablish the appropriate tension, the suture-passing instrument should enter the capsule approximately 1 cm posterior and inferior to the planned anchor site. In the inferior capsule, one needs to be careful to avoid passing the device too deeply into the soft tissue to avoid injury to the axillary nerve. Once this anchor has been placed, the surgeon should note the reduction of the inferior capsular redundancy. The suture can then be cut with an arthroscopic suture cutter. It is important to cut the suture without tails to prevent mechanical irritation and damage to the articular surface. This process is then repeated from an inferior to superior direction in order to elevate the labral tissue back to the glenoid and to restore tension. For typical Bankart lesions, we use three anchors; however, this is ultimately dictated by the size of the labral tear.

Posterior Glenohumeral Instability

Many of the technical aspects of arthroscopic posterior instability repairs are similar to anterior repairs. A complete diagnostic arthroscopy should be performed with careful inspection of the posterior labrum and capsule. With careful inspection, one may encounter a reverse Bankart lesion or a reverse Hill Sachs lesion. Injuries to the posterior capsule, a posterior HAGL, or a Kim lesion (incomplete avulsion of the posterior labrum) may also be present. As with anterior instability, the labrum is elevated to an anatomic position and the associated capsulolabral tears are repaired with the use of
suture anchors. However, in these procedures, the process of placing anchors begins anteriorly and progresses posteriorly to recreate the sling effect of the PIGHL and to decrease the posterior capsular volume.

Multidirectional Instability

The surgical repair for multidirectional instability involves capsular plication. It requires the same basic setup and portal placement as is noted with the anterior instability repair. However, in this procedure, the main focus is addressing the generalized capsular laxity. To do this, anchors are placed along the glenoid rim with the focus on trying to remove the capsular redundancy that leads to multidirectional instability. In what is called a pinch-tuck technique, anchors are placed and then a “pinch” of capsular tissue is obtained with an arthroscopic suture passer; the capsular tissue is then tied down to the anchor. This decreases the capsular volume and stabilizes the shoulder. As with anterior or posterior instability, stabilization proceeds from inferior to superior. To encourage the redundant capsular tissue to scar to itself and permanently decrease the capsular volume, the surface of the capsule is abraded with a rasp prior to suture plication. If additional capsular plication is desired to further decrease the capsular volume, plication stitches without anchors can be placed around the intact labrum in areas between the previously placed suture anchors.

Postoperative Rehabilitation

Rehabilitation plays a vital role in the functional outcome following shoulder stabilization surgery. The goal of the postoperative treatment is to ensure a balance between mobility and stability. We utilize a criteria-based approach to rehabilitation that divides the rehabilitation into 4 progressive phases, each tailored to the specific surgical procedure. Each phase consists of specific goals and exercises that are designed to systematically introduce forces and loads to the healing tissues while avoiding overstressing them. It is the intent of these programs to serve as a guideline. therefore, based on the patient and surgical intervention, the clinician will be able to make appropriate adjustments to each program. Although there are many common principles that can be applied to the rehabilitation of all instability repairs, there are also specific differences that relate to the direction of instability as well as to the repair.

When designing a shoulder instability rehabilitation program, the therapist must take into account several patient-related (Table 5.1) and surgery-related (Table 5.2) variables that may impact the rehabilitation. First, healing tissues should never be overstressed; therefore, the program must be progressive and sequential, with each phase building from the prior phase. Based on our experience of poorer outcomes following prolonged immobilization followed by a rapid progression of ROM, we implement the restoration of ROM in a gradual, systemic format with stretching precautions for the first 8 to 10 weeks following surgery. Second, the effects of immobilization must be minimized, especially in the overhead athlete. After shoulder stabilization surgery, a short period of immobilization may be indicated to allow initial healing. During this phase, however, the clinician can incorporate mild dynamic stabilization drills, gentle restricted passive motions, and submaximal isometrics to enhance dynamic stability, assist in collagen organization, and prevent loss of motion. In addition, the quality of end feel should be continually monitored throughout the rehabilitation by applying a slight overpressure at the end range of passive ROM (PROM). If a firm or hard end feel is noted, the clinician may accelerate the rate of ROM progression; with a soft or empty end feel, the patient’s stretching program will be slowed. Third, the patient must fulfill specific criteria to progress from one phase to the next, thus allowing the rehabilitation program to be individualized based on the patient’s unique healing rate and constraints. Finally, a successful outcome is related to a team effort, with the physician, therapist, and patient all working together toward a common goal.

Table 5.1 PATIENT FACTORS AFFECTING THE REHABILITATION PROGRAM

Patient’s tissue status
Hyperelasticity ↔ hypermobility
Dynamic stabilizers status
Muscle–bone
Muscular strength and balance
Proprioceptive ability
Classification of instability
Previous activity level
Desired activity level (expectations)
Healing abilities (rapid healers, slow healers)

Table 5.2 SURGICAL FACTORS AFFECTING THE REHABILITATION PROGRAM

Type of surgical procedure (exposure, specific procedure, tissue used)
Method of fixation
Type of instability (instability classification)
Patient’s tissue status (hyperelasticity, normal, hypoelasticity)
Patient’s response to surgery
Patient’s dynamic stabilization (muscle strength, dynamic stability, proprioception)
Patient’s activity level (past, present, desired goals)
Physician’s philosophical approach