Arthroscopic Superior Labrum Anterior-to-Posterior Repair

James C. Dreese, MD

Danielle Casagrande, MD

Dr. Dreese or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Cayenne Medical and serves as a paid consultant to or is an employee of Cayenne Medical. Neither Dr. Casagrande 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 chapter.

INTRODUCTION

Superior labrum anterior-to-posterior (SLAP) tears have become increasingly recognized with the improved diagnostic capability of arthroscopy and advanced imaging modalities. First described in a group of throwing athletes by Andrews et al¹ in 1985, SLAP tears were further classified by Snyder et al² in 1990. Common to all SLAP tears is the detachment of the superior labrum, with or without involvement of the biceps anchor.

Classification

The original Snyder classification system remains the most widely recognized; it describes four types of SLAP lesions (Figure 1). Type I lesions involve fraying on the inner margin of the superior labrum and local degeneration. The superior labrum and biceps anchor remain attached and stable. These lesions are believed to result from age-related degenerative changes and are common in the middle-aged and elderly. Type I lesions are thought to be largely asymptomatic. The type II lesion is the most common type of SLAP tear requiring repair. Type II lesions are characterized by detachment of the superior labrum and biceps tendon anchor from the superior glenoid rim. Abnormal mobility of the superior labrum and biceps anchor is present, resulting in an unstable lesion. Numerous authors have described successful repair of type II SLAP lesions.³^,⁴^,⁵^,⁶^,⁷^,⁸^,⁹^,¹⁰^,¹¹^,¹²^,¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹^,²⁰^,²¹^,²²^,²³^,²⁴ In 1998, Morgan et al³ further classified type II SLAP tears into three subvariants. The anterior variant and posterior variant represent isolated anterior and posterior detachments, respectively, of the superior labrum and biceps complex; the posterior subtype is most common in throwing athletes. The anterior and posterior variants represent a combined detachment of the anterior and posterior labrum and biceps complex. Type III SLAP lesions demonstrate a bucket-handle tear of the superior labrum with an intact biceps anchor. When the mobile fragment is large, it may displace into the glenohumeral joint, resulting in mechanical symptoms and pain. Type IV SLAP lesions involve a bucket-handle tear with extension of the labral tear into the biceps tendon. Typically, a portion of the biceps attachment to the superior glenoid remains intact despite the unstable torn portion.

In 1995, Maffet et al⁶ described three additional SLAP variants with injury patterns involving both the superior labrum-biceps anchor complex and labrum. A type V SLAP lesion describes a type II lesion with anterior extension involving the anterior-inferior labrum. Type VI lesions are characterized by an unstable anterior or posterior flap of the superior labrum in conjunction with a type II lesion. Type VII lesions are type II lesions with a separation of the biceps attachment extending into the middle glenohumeral ligament, rendering it incompetent. Powell et al⁷ described three additional SLAP variants: type VIII is a type II lesion with posterior labral extension, type IX is a type II lesion with a circumferential labral tear, and type X is a type II lesion with a posteroinferior labral tear.

Clinical Diagnosis

Clinical diagnosis of SLAP tears can be difficult. The superior labrum injury often occurs in conjunction with other shoulder pathology, such as an anterior/posterior labral tear and rotator cuff tears. The most common presenting symptom is pain, which may be described as sharp or aching and may be anterior or posterior in location. No single examination finding has been proven to be both highly sensitive and specific for SLAP tears.⁸

Suspicion of SLAP pathology is based on injury mechanism, physical examination, and radiographic evaluation. Nonsurgical treatment includes rest from aggravating activities, nonsteroidal anti-inflammatory drugs, posterior capsule stretching, and strengthening of the rotator cuff and scapular stabilizers. An intra-articular injection may give patients temporary pain relief and confirm the glenohumeral joint as the source of discomfort.

PATIENT SELECTION

Indications

Indications for surgical treatment are variable. In general, if a 3-month trial of nonsurgical measures fails to alleviate the patient’s symptoms, consideration of arthroscopy
is warranted. Arthroscopy remains the benchmark in the diagnosis and treatment of SLAP lesions. Arthroscopic identification of normal superior labrum-biceps complex variants is crucial to avoid unnecessary repair and potential resultant complications. In most instances, type I SLAP tears are considered a normal finding that does not require treatment. Type II lesions should be repaired when the physical examination is consistent and arthroscopy does not reveal another explanation for the patient’s pain. Repair of type II SLAP tears has evolved in the past 20 years. Techniques involving the use of arthroscopic tacks, staples, and suture anchors have been described with varying success.³^,⁴^,⁵^,⁹ Careful evaluation of all pathologies should be considered in determining the etiology of the pain and the most effective treatment. Although outcomes following repair of type II SLAP tears with suture anchors in young, active patients generally have been good, repair of incidental degenerative SLAP tears in older patients with concomitant shoulder pathology such as rotator cuff tears should be avoided.⁴ A randomized controlled trial in patients older than 50 years with both rotator cuff and labral pathology revealed better clinical results with combined rotator cuff repair and biceps tenotomy than with rotator cuff repair and SLAP repair.¹⁰ Biceps tenodesis may be a more effective treatment than SLAP repair for type II tears in patients older than 40 years.¹¹ Pathologic findings with a stable biceps anchor (type III and some type IV lesions) often can be treated adequately with débridement of the unstable fragment alone. When resecting the unstable bucket-handle fragment, care must be taken to not destabilize the middle glenohumeral ligament. Type IV lesions may be treated with repair, biceps tenodesis, or biceps tenotomy. Young patients with minimal involvement of the biceps anchor are good candidates for débridement of the unstable fragment alone or direct suture anchor repair. As with type II tears, active patients with a partial-thickness tear of the biceps tendon greater than 25%, chronic atrophic changes of the tendon, subluxation of the tendon from the bicipital groove, or tendon atrophy such that the tendon is less than 75% its normal width may benefit from biceps tenodesis.¹² Low-demand patients with extensive partial-thickness tearing, evidence of subluxation, or both are candidates for biceps tenotomy. Type V through type X SLAP tears are a combination of superior labral injuries and disruption of the capsule and labrum. Treatment is directed at anatomic restoration of the labral and ligamentous attachments. As with type IV lesions, SLAP repair, biceps tenodesis, and biceps tenotomy may be appropriate depending on the patient’s age and the arthroscopic findings.

FIGURE 1 Illustration shows the Snyder classification of superior labrum anterior-to-posterior (SLAP) tears. Type I: Local degeneration and fraying on the inner margin of the superior labrum are seen. Type II: The superior labrum and biceps tendon anchor are detached from the superior glenoid rim. Type III: A bucket-handle tear of the superior labrum is present; the biceps anchor is intact. Type IV: The bucket-handle tear extends into the biceps tendon.

Contraindications

Contraindications to the surgical management of SLAP lesions may be absolute or relative. Absolute contraindications include the presence of active infection and medical comorbidities—the risks of which outweigh the potential benefits of repair. The presence of a normal superior labral anatomic variant such as a sublabral foramen or Buford complex rather than a SLAP tear also is an absolute contraindication. Relative contraindications include older patients with concomitant findings that explain their disability, such as rotator cuff tears. Adhesive capsulitis should be managed nonsurgically initially, despite findings of a possible SLAP tear. Evidence of extensive tearing of the long head of the biceps, biceps subluxation, and extensive degenerative tearing of the long head of the biceps are all relative contraindications to SLAP repair and are better suited for tenodesis or tenotomy. Determination of the best treatment for each patient is made based on the preoperative symptoms, age of the patient, and surgical findings. Preoperative consultation with the patient regarding possible treatments is necessary to establish better understanding and expectations of treatment alternatives and expected outcomes.

PREOPERATIVE IMAGING

Diagnostic imaging begins with standard shoulder radiographs: glenoid AP, acromioclavicular AP, scapular Y, and axillary views. Plain radiographs rule out other potential sources of shoulder pain such as degenerative arthritis of the glenohumeral and acromioclavicular joints.

MRI is the study of choice in evaluating SLAP pathology, rotator cuff injuries, and labral pathology. The presence of a paralabral cyst within the spinoglenoid notch is highly suggestive of a SLAP tear. Understanding normal anatomic variation in the superior labrum-biceps complex is critical to the identification of pathologic SLAP tears. An arthroscopic study of 546 patients revealed a 3.3% incidence of a sublabral foramen, an 8.6% incidence of a sublabral foramen with a cord-like middle glenohumeral ligament, and a 1.5% incidence of an absent anterosuperior labrum with a cord-like middle glenohumeral ligament (Buford complex).¹³ Conventional MRI has been reported to be 84% to 98% sensitive and 63% to 91% specific in the detection of SLAP tears.¹⁴^,¹⁵

Magnetic resonance arthrography (MRA) includes an intra-articular contrast injection in conjunction with MRI. If adequate distension of the joint is achieved, extravasation of contrast into or underneath the superior labrum-biceps complex is highly suggestive of SLAP pathology. Although debate exists about whether MRA or high-resolution MRI is more effective in diagnosing SLAP tears, MRA is undeniably more effective than low-resolution MRI in making the diagnosis. Both coronal and axial images are particularly helpful in making the diagnosis using multiplanar MRI. A distinction between normal superior labrum-biceps complex variants and findings of SLAP tears must be made.

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