Shoulder SLAP Lesion

SLAP Lesion is the abbreviation of Superior Labrum from Anterior to Posterior tears in the shoulder joint labrum.

It may occur as isolated lesion or it can be associated with:

1. Internal impingement of the shoulder.
2. Rotator cuff tears (usually articular sided tears).
3. Shoulder Instability (may be subtle)

SLAP Lesion of the shoulder is most common occurs in a throwing athlete (repetitive overhead activities). It comprise approximately 5% of all shoulder injuries.

In 1985, Andrews et al. were the first investigators to describe lesions to the proximal biceps tendon with involvement of the superior aspect of the glenoid labrum. Later, Snyder et al. coined the term “SLAP” tear due to the anterior to posterior direction of labral tearing.

See Also: 
- Rotator Cuff of the Shoulder
- Anterior Shoulder Instability

SLAP Tear Causes

Tension of the long head of the biceps tendon, such as that experienced during the follow-through phase of pitching when the biceps works to decelerate the elbow, pulls the labrum away from the glenoid fossa. Other compression and inferior traction mechanisms can also produce SLAP lesions.

Repetitive traction from participation in overhead throwing sports such as baseball and softball also commonly result in tearing of the superior labrum.

A forceful compression load may trap the biceps labrum complex between the humeral head and the superior glenoid rim which may produce a mechanical shearing effect (or “grinding,” as suggested by Snyder et al.) resulting in a tear of the superior labrum.

The long head of the biceps tendon contacting the rotator cuff when the arm is in the cocked position has been associated with posterior-superior tears. Type II lesions can occur by the long head of the biceps tendon being peeled back caused by tendon torsion created as the arm is brought into abduction and external rotation.

Classification (Expanded Snyder classification)

Snyder et al. classified SLAP tears into four groups which were later supplemented by three additional groups (types I–VII).

Type II SLAP tears have been further classified relative to the detachment of the labrum:

1. Isolated to the anterior aspect.
2. Isolated to the posterior aspect.
3. Appearing in both aspects.

Type I tears are most frequently associated with rotator cuff degeneration; GH instability is often the precursor to Type III and IV tears . Type II tears, the most common type, are age dependent. In younger patients, Type II tears tend to clinically resemble those of Type III and IV tears in adults; in older patients, Type II tears more closely resemble Type I.

Physical Examination:

With an acute or gradual onset, SLAP lesions present with clinically inconsistent symptoms and are frequently associated with concurrent pathology.

The chief complaint is of pain between the AC joint and coracoid process during overhead arm movement that is relieved by rest. Throwing athletes report “dead arm” symptoms and a loss of throwing control and velocity. The location, quality, and intensity of pain related to a SLAP tear may differ across a population.

SLAP tears are rarely isolated and typically occur concomitantly with other painful shoulder conditions. Thus, the pain from a concomitant pathologic lesion, such as a partial thickness rotator cuff tear, could mask, enhance, or mimic the pain produced by a possible SLAP tear, potentially confusing the clinical picture.

There is no single physical examination maneuver specific for SLAP tear, some tests may rise suspicious of it:

1. O’Brien Test
2. Compression rotation test
3. Speed test
4. Dynamic labral shear test
5. Kibler anterior slide test
6. Crank test
7. Kim biceps load test.

Tests for SLAP tend to yield false-positive results because of the presence of concurrent GH or AC pathologies. In other cases, procedures may produce pain caused by a SLAP lesion but be negative for the pathology being tested. For example, the Neer impingement test may be negative for rotator cuff involvement but evoke pain caused by a SLAP lesion.

See Also: Shoulder Special Tests

Oh and colleagues studied the usefulness of combinations of two and three special tests in identifying type II. Although combinations of two tests were not useful in substantially increasing the overall diagnostic utility, several combinations of three tests were. When two tests were chosen from the group with relatively high sensitivities and one from the group with relatively high specificities, the sensitivities of the three “or” combinations were approximately 75% and the specificities of the three “and” combinations were approximately 90%.

Diagnostic Utility of Combinations of Tests for Identifying Type II to IV:

Imaging:

• MR arthrography is the modality of choice.
• A paralabral cyst is indicative of a SLAP tear (or posterior labral tear): Cyst may extend to spinoglenoid notch and compress the suprascapular nerve, leading to infraspinatus wasting.

SLAP Tear Treatment

Nonoperative Treatment:

Nonoperative treatment of SLAP tear should be tried in all patients.

Treatments include:

1. Rotator cuff muscles strengthening and scapular stabilization.
2. Throwers benefit from stretching of the posterior capsule.
3. Intraarticular injections.

Operative Treatment:

Surgical technique SLAP repair is selected based on the type of the tear as mentioned in the table above.

Some suggests that patients older than 40 years with obvious biceps pathology and degenerative labral changes are best treated with débridement and tenotomy/ tenodesis.

If concomitant rotator cuff tear presents, recent studies have found no advantage to repairing SLAP at time of rotator cuff repair as it may result in increased rate of shoulder stiffness if SLAP tears is repaired.
Recent studies have suggested biceps tenotomy should be performed at the time of rotator cuff repair.

Postoperative management of a patient with a SLAP lesion depends on whether the tear was debrided or repaired. Although cases of debridement can usually progress as tolerated, repairs of SLAP lesions progress more slowly. Most importantly after a surgical SLAP repair, contraction of the biceps tendon and other traction forces from the tendon placed on the repair must be controlled for 6 to 8 weeks.

SLAP Repair Protocol with Rehab

• After SLAP repair, there is relatively high incidence of postoperative stiffness, so motion is begun early ( Pendulums are initiated immediately).
• Passive and active assisted exercises are begun 7 to 10 days postoperatively.
• Patient should avoid resistive biceps exercises and external rotation with the arm in 90 degrees of abduction.

Complications

1. Shoulder stiffness is common after SLAP repair.
2. Stiffness should be initially managed with physical therapy. If symptoms persist, arthroscopic capsular release may be performed.
3. Persistent symptoms, articular cartilage injury, and loose or prominent hardware are other frequent complications following SLAP tears repair.

References

1. Michener LA, Doukas WC, Murphy KP, Walsworth MK. Diagnostic accuracy of history and physical examination of superior labrum anterior- posterior lesions. J Athl Train. 2011 Jul-Aug;46(4):343-8. doi: 10.4085/1062-6050-46.4.343. PMID: 21944065; PMCID: PMC3419145.
2. Oh JH, Kim JY, Kim WS, Gong HS, Lee JH. The evaluation of various physical examinations for the diagnosis of type II superior labrum anterior and posterior lesion. Am J Sports Med. 2008 Feb;36(2):353-9. doi: 10.1177/0363546507308363. Epub 2007 Nov 15. PMID: 18006674.
3. Powers, R: SLAP lesions: how to recognize and treat this debilitating shoulder injury. JAAPA, 24:32, 2011.
4. Kim, TK, et al: Clinical features of the different types of SLAP lesions: an analysis of one hundred and thirty-nine cases. J Bone Joint Surg, 85(A):66, 2003.
5. Cook, C, et al: Diagnostic accuracy of five orthopedic clinical tests for diagnosis of superior labrum anterior posterior (SLAP) lesions. J Shoulder Elbow Surg, 21:13, 2012.
6. O’Brien, SJ, et al: The active compression test: a new and effective test for diagnosing labral tears and acromioclavicular joint abnormalities. Am J Sports Med, 26:610, 1998.
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8. Walsworth, MK, et al: Reliability and diagnostic accuracy of history and physical examination for diagnosing glenoid labral tears. Am J Sports Med, 36:162, 2007.
9. Andrews JR, Carson Jr WG, McLeod WD. Glenoid labrum tears related to the long head of the biceps. Am J Sports Med. 1985;13(5):337–41.
10. Snyder SJ, Banas MP, Karzel RP. An analysis of 140 injuries to the superior glenoid labrum. J Shoulder Elbow Surg. 1995;4(4):243–8.
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13. Millers Review of Orthopaedics -7th Edition Book.