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Basics ⬇

Author: BrianLowell, MD, CAQSM

Description

  • The anatomy of the glenohumeral (GH) joint is complex, and stability is provided from combination of the capsule, tendons, muscles, bones, and the labrum:
    • Labrum acts by increasing surface area for humeral head contact.
    • Provides attachment site for GH ligament and the tendon of the long head of the biceps
    • Composed of fibrocartilage and dense fibrous collagenous tissue
    • The superior aspect is more mobile than the inferior portion that is tightly attached to the glenoid rim.
    • Multiple anatomic variations exist: congenitally absent portions of the labrum, different anchor sites for the GH ligament, different biceps tendon origins, and superior labral recesses (1).
  • There are currently 10 described SLAP lesions (superior labrum anterior-to-posterior), of which the four originally described by Snyder are the most common:
    • Type I is degenerative fraying of the labrum.
    • Type II is a detached labral/biceps complex.
    • Type III is a bucket-handle tear.
    • Type IV is a bucket-handle tear with extension into the biceps tendon (2).
  • SLAP lesions occur as acute injuries or with chronic degradation.

Epidemiology

  • Incidence of SLAP lesions is relatively low, occurring in approximately 3–6% of all arthroscopic shoulder cases.
  • Reported to occur in up to 25% of patient with symptomatic shoulder instability
  • More common in men than women
  • Most commonly seen in individuals in their mid-20s

Etiology and Pathophysiology

  • SLAP lesion development consists of an internal rotation deficit, tightening of the posterior capsule, posterior superior GH shift, maximization of external rotation forces at the biceps anchor and superior labral attachment, and “peel back” of the labrum. Alterations in scapular movements (dyskinesis) exacerbate this mechanism (1).
  • Mechanisms of injury to the glenoid labrum occur via acute trauma or repetitive microtrauma from overhead motions:
    • Acute mechanism of injury:
      • Compression due to a fall on an outstretched arm or onto an adducted shoulder
      • Traction injury from a swift pull
      • Humeral head shearing such as during vehicle accidents from seat belt restraint
    • Chronic mechanism of injury:
      • Secondary to repetitive motions that result in micro trauma accumulation
      • Chronic instability

Risk-Factors

  • Repetitive overhead motions (sports or occupational):
  • Shoulder instability/trauma
  • Anatomic variation or underlying generalized laxity/instability

General Prevention

  • There are no definitive guidelines for prevention of SLAP lesions. Generally, physical therapy practices are followed:
    • Rotator cuff strengthening
    • Scapular stabilizer strengthening
    • Posterior capsule stretching
    • Limiting internal rotation deficits
    • Ensuring proper overhead mechanics
  • Additionally, monitoring pitch counts in the youth has been implemented as a preventative technique.

Commonly Associated Conditions

Labral tears are commonly associated with other underlying shoulder problems, as forces that cause labral injuries can cause other pathology. Thus, a high index of suspicion is required when evaluating for SLAP lesion, as other shoulder pathology coexist in approximately 85% of cases (Bankart lesions, GH instability, rotator cuff, and bicipital tendon pathology). This can significantly confound the diagnosis.

Diagnosis ⬆ ⬇

Labral tear diagnosis is made by history, physical, and appropriate imaging. The gold standard for diagnosis of a SLAP lesion is direct visualization via arthroscopy.

History

  • Most individuals complain of nonspecific shoulder pain. Commonly anterior/superior in nature. Patient’s experience is extremely variable.
  • Other pertinent positives in the history may include:
    • Acute injury or repetitive overhead motion (sport, hobby, occupational).
    • Mechanical symptoms: catching, clicking, or popping deep within the shoulder with overhead movements.
    • Decrease in athletic performance (strength, velocity, accuracy, precision).
    • Weakness in the upper extremity.
    • Sense of instability.

Physical Exam

  • Examination maneuvers are generally inaccurate; there is no gold standard clinical test.
  • Combinations of clinical tests provide higher accuracy. Combining two tests from a group with relatively high sensitivity (compression rotation test, anterior apprehension test, or O’Brien test) with one test from a group with relatively high specificity (Yergason test, biceps load test II, or Speed test) results in sensitivity and specificity of nearly 75% and 90% respectively (3).
  • Relatively high-sensitivity tests:
    • Compression rotation test: With patient supine, the patient’s arm is abducted to 90 degrees and the elbow is flexed to 90 degrees while the examiner applies axial force to the humerus; positive if pain or clicking is noted
    • Anterior apprehension test: With patient supine, examiner passively abducts and externally rotates the humerus; positive if pain or sensation of instability is noted
    • O’Brien test: With patient standing, the arm is forward flexed to 90 degrees with the elbow in full extension. With an adducted arm to 10 degrees and an internally rotated humerus, the examiner applies downward force to the arm as the patient resists. Patient then fully supinates the arm and repeats resistance; positive if pain is elicited with internal rotation and reduced with external rotation (supination)
  • Relatively high-specificity tests:
    • Yergason test: With patient standing with elbow at 90 degrees of flexion, patient supinates forearm against examiner’s resistance while examiner palpates long head of biceps tendon; positive if pain at biceps tendon
    • Biceps load II test: With patient supine, examiner grasps patient’s wrist and elbow. The arm is abducted 120 degrees and fully externally rotated (apprehension position), with elbow held in 90 degrees of flexion and forearm supinated. Examiner then resists elbow flexion by patient; positive if pain is noted
    • Speed test: With patient seated, elbow extended and forearm in full supination, the clinician resists active forward flexion from 0 to 60 degrees; positive if pain is increased in the shoulder and the patient localizes the pain to the bicipital groove (3)[C]

Differential Diagnosis

  • GH arthritis
  • Rotator cuff impingement, tendinopathy or tear
  • Biceps tendinopathy, tear or subluxation
  • Shoulder instability
  • Acromioclavicular (AC) joint disorder
  • Cervical radiculopathy or other referred pain
  • Paralabral ganglion cyst
  • Pain syndromes (complex regional pain or Parsonage-Turner syndrome)

Diagnostic Tests & Interpretation

Initial Tests (lab, imaging)

  • Plain radiographs are useful in identifying bony pathology such as fracture, GH arthritis, AC joint arthritis, and calcific deposits.
  • Ultrasound is useful in evaluating for coexistent injuries (biceps tendon, rotator cuff tendons, joint capsule, and AC joint) but is insensitive for labral pathology. Joint effusion, bicipital sheath effusion, and paralabral cysts are secondary findings that suggest intra-articular pathology, which may include SLAP lesion.
  • Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) are the mainstays in imaging for SLAP lesions.
  • Arthrography with contrast medium improves imaging by outlining the intra-articular and synovial surfaces through slight distension of the capsule:
    • Direct (intra-articular) MRA is superior to plain MRI and vascular contrast-enhanced MRI for detecting SLAP lesions with respect to both sensitivity and specificity (4)[A].

Diagnostic Procedures/Other

GH arthroscopy:

  • Gold standard
  • Most sensitive and specific test for labral pathology
  • Evaluation of the biceps labral complex should be done with a probe because it may appear normal with just visualization.

Treatment ⬆ ⬇

General Measures

  • Ideal treatment of SLAP injuries remains unclear. Current recommendations support an initial nonsurgical approach prior to surgical intervention.
  • Initial therapy (nonoperative):
    • Relative rest from aggravating activities
    • Physical therapy with a focus on endurance and strengthening of the rotator cuff and scapular stabilizers and posterior capsule stretching to assist with limitations on internal rotation (2)[C]
    • A history of trauma or participation in overhead activities is strongly associated with failure of nonoperative treatment.

Medication

  • Oral pain control should be considered with nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen.
  • With minimal pain relief from oral pharmacologics, subacromial or intra-articular corticosteroid injection can be considered.

Issues for Referral

  • Referral to a surgical specialist should be made if a patient is experiencing persistent symptoms despite 3 to 6 mo of adequate physical therapy.
  • Consider early referral in elite and overhead athletes for possible faster return to sport.

Surgery/Other Procedures

  • Evaluation with diagnostic arthroscopy and treatment is indicated if initial treatment interventions do not appropriately manage symptoms.
  • Although there is no uniform approach to SLAP lesion surgical repair, several options are available (débridement, SLAP repair/fixation, subacromial decompression, tenotomy of the long head of the biceps tendon, and tenodesis of the long head of the biceps) (5)[C].
  • Due to discouraging surgical results (poor outcomes with respect to return to previous level of play and surgical complications) with SLAP repair, biceps tenodesis is becoming more prevalent (5)[C].
  • Other surgical intervention may be required depending on associated conditions such as rotator cuff tears or instability.

Ongoing Care ⬆ ⬇

  • Postoperative care varies among individuals and depends on overall surgical intervention. Therapy is largely patient directed.
  • Example of postoperative therapy are as follows:
    • Sling immobilization to protect shoulder for first 4 wk
    • Shoulder, elbow, and hand ROM for first 4 wk; full ROM typically achieved by 10 wk
    • Restore strength/balance and begin isotonic rotator cuff strengthening 8 to 12 wk postoperatively.
    • Plyometric training at approximately 20 wk
    • Throwing exercises between 24 and 28 wk
    • Return to activity 6 to 9 mo (2)[C]

Follow-up Recommendations

Rigorous follow-up is recommended with nonsurgical and surgical management of SLAP lesions.

Prognosis

  • Contact athletes typically return to sport quicker than overhead athletes and had a greater percentage of athletes return to their prior level of play. The evidence is rather unfavorable for overhead athletes returning to prior level of play status post SLAP repair (40–70%).
  • Return to play and return to previous level was limited in pitchers compared to other positional players in baseball.
  • Individuals with isolated SLAP lesions (rare) return to activity much quicker (2.6 mo) than individuals with concomitant shoulder pathology (6 mo).
  • Age appears to affect outcomes because younger athletes appear to do better overall (6)[C].

Complications

Complications associated with surgical intervention include infection, hemarthrosis, failed surgical intervention, instability, adhesive capsulitis, and chondral injury.

References ⬆ ⬇

  1. Abrams G, Safran M. Diagnosis and management of superior labrum anterior posterior lesions in overhead athletes. Br J Sports Med. 2010;44(5):311–318.
  2. Manske R, Prohaska D. Superior labrum anterior to posterior (SLAP) rehabilitation in the overhead athlete. Phys Ther Sport. 2010;11(4):110–121.
  3. Oh JH, Kim JY, Kim WS, et al. The evaluation of various physical examinations for the diagnosis of type II superior labrum anterior to posterior lesion. Am J Sports Med. 2008;36(2):353–359.
  4. Symanski JS, Subhas N, Babb J, et al. Diagnosis of superior labrum anterior-to-posterior tears by using MR imaging and MR arthrography: a systemic review and meta-analysis. Radiology. 2017;285(1):101–113.
  5. Popp D, Schöffl V. Superior labral anterior posterior lesions of the shoulder: current diagnostic and therapeutic standards. World J Orthop. 2015;6(9):660–671.
  6. Rangavajjula A, Hyatt A, Raneses E, et al. Return to play after treatment of shoulder labral tears in professional hockey players. Phys Sportsmed. 2016;44(2):119–125.

Clinical Pearls ⬆

  • Glenoid labral tears are relatively uncommon shoulder injuries but are more commonly seen in overhead athletes and those who participate in contact sports.
  • Labral injuries typically cause vague pain, decreased performance, and mechanical symptoms. Physical exam, although helpful, is unreliable for definitive diagnosis, so have a low threshold for imaging in appropriate cases.
  • Generally, nonsurgical treatment is indicated prior to surgical intervention.
  • Evaluation with diagnostic arthroscopy and treatment is appropriate if nonsurgical therapy does not manage symptoms.
  • Consider early referral in elite and overhead athletes for possible faster return to sport.
  • The evidence is rather unfavorable for overhead athletes returning to prior level of play status post SLAP surgical repair. If no labral pathology is identified, broaden differential to include cervical or brachial plexus pathology.