What is a SLAP tear?

Description

The term SLAP stands for Superior Labrum Anterior and Posterior. In a SLAP injury, the superior (top) part of the labrum is injured. This top area is also where the long head of the biceps tendon attaches to the labrum. A SLAP tear occurs both in the front (anterior) and back (posterior) of this attachment point. The biceps tendon can be involved in the injury, as well (1). Synder et. al: Arthroscopy 1990, identified 4 different types of SLAP tears (2).

• Type I: This involves degenerative fraying of the labrum.

• Type II: Type II SLAP tears are the most common type of SLAP tear. This includes avulsion of the superior labrum and long head of the biceps tendon.

• Type III: This includes a bucket handle tear of the superior labrum with an intact biceps tendon.

• Type IV: This is a bucket handle tear of the superior labrum with extension into the biceps tendon.

Type I Type II Type III Type IV

Pathogenesis

• Varacallo et al., identified three main mechanisms of injury including acute traumatic SLAP lesions, attritional SLAP lesions, and degenerative SLAP lesions (3).

Acute Traumatic SLAP injuries:

• Compression-type injuries: These are a result of falling on an outstretched hand (FOOSH mechanism) with the arm in varying degrees of shoulder abduction (3).

• Traction-type injuries: These occur secondary to sudden jerking movements or after lifting heavy objects. Can occur after an unexpected pull on the arm (3).

• Combined-type injuries

Attritional SLAP Injuries:

• Peel-back Mechanism: Compared to the acute-traumatic SLAP injuries, the overhead athlete is more likely to present with attritional-based etiologies. In these scenarios, SLAP tears present with the insidious onset and progressive deep shoulder pain in young athletes with the arm in the abduction and external rotation position during the late-cocking phase of throwing. In this position, the force on the biceps coupled with the posterior glide of the humerus results in the peeling off of the posterior superior quadrant of the glenoid and posterior labrum (3).

Late-Cocking Phase:

Degenerative SLAP Injuries:

• Degenerative SLAP tears can develop secondary to the normal "anatomical changes" seen in patients of advanced age. Degenerative SLAP tears often affect overhead laborers with increasing degrees of association in patients over 40 years old (3).

Clinical Presentation

• Pain is typically described deep inside the joint and/or located in the posterior shoulder.

• Symptoms typically begin with complaints associated with rotator cuff disease and glenohumeral instability.

• Complaints may include popping and/or the perception of catching sensations; especially with overhead activities.

• Progression of clinical symptoms includes increased complaints of pain; especially with overhead activities, progressive weakness and stiffness, progressive loss of endurance and ROM, and related dysfunction (4).

Special Tests

• O'Brien's Active Compression Test: Stabilize scapula with one hand, flex shoulder to 90 degrees with slightly horizontally ADD, eccentrically load shoulder flexors with arm IR, repeat with arm ER. A positive test is when pain or painful click inside the shoulder or pain at the AC joint (with IR >>ER). Sensitivity up to 100%, and Specificity 98.5% for labral abnormality. +LR 66.66. Specificity for AC joint abnormality is 96.6% and Sensitivity 100% (5).

• Anterior Slide Test: Stabilize the scapula and clavicle, apply anterior superior force through the patient’s elbow, palpate the humeral head. A positive test is when the humeral head slides forward with a pop or pain. Specificity 84-92% for a labral tear and Sensitivity 8-78%. +LR 9.22, -LR 0.34 (5).

• Bicep's Load Test II: Perform an apprehension test by taking the arm into full ER, if apprehension appears, the examiner stops lateral rotation and holds the position, ask the patient to flex the elbow against resistance. A positive test is when the patient has apprehension that remains the same or the shoulder becomes more painful. Sensitivity 90%, Specificity 97% (6).

• Posterior-Inferior Labral Lesion: Arm abducted to 90°, the examiner holds the elbow and lateral aspect of the proximal arm, and a strong axial loading force is applied, while the arm is elevated 45°diagonally upward, downward and backward force is applied to the proximal arm. A positive test is when there is a sudden onset of posterior shoulder pain, regardless of accompanying posterior clunk of the humeral head. Sensitivity 73%, Specificity 98%. Image from Kim SH et al (9).

• Dynamic Speed's Test: The patient flexes arm to 90°with the forearm supinated, and apply an eccentric force into extension, repeat with the arm pronated. A positive test is when there is increased pain in the bicipital groove with the forearm supinated. Sensitivity 87%, Specificity 80% for long head biceps tear or tendinitis (5). Image from 5minuteconsult.com.

• Compression Rotation Test: Longitudinal compression through the humerus, and rotate humerus medially and laterally. A positive test is when there is any snapping or catching. Heegdus found this test to have the best +LR for SLAP (2.81) (7). Image from www.mikereinold.com.

• Clunk Test: Place hand posterior aspect of the humeral head, hold humerus above the elbow, fully ABD arm, apply an anterior pressure to the humeral head while other hand ER shoulder. A positive test is when a clunk or grind occurs or if there is apprehension. Sensitivity 44%, Specificity 68%, +LR 1.4 (5).

• Crank Test: Elevate arm to 160 °in the scapular plane, apply an axial load to humerus while IR and ER shoulder. A positive test is when there is pain or reproduction of symptoms especially with ER with or without clicking. Sensitivity 91%, Specificity 93%, +LR 13.6, -LR 0.1. Image from https://www.youtube.com/watch?v=3CLvoC21hTo.

• Pronated Load SLAP Test: This test is performed in the supine position with the shoulder abducted to 90° and externally rotated. However, the forearm is in a fully pronated position to increase tension on the biceps and subsequently the labral attachment. When maximal external rotation is achieved, the patient is instructed to perform a resisted isometric contraction of the biceps to simulate the peel-back mechanism. This test combines the active bicipital contraction of the biceps load test with the passive external rotation in the pronated position, which elongates the biceps. A positive test is indicated by discomfort within the shoulder (10). Image from www.mikereinold.com.

• Resisted Supinated External Rotation SLAP Test: In this test, the patient is positioned in 90° of shoulder abduction, and 65-70° of elbow flexion and the forearm in a neutral position. The examiner resists against a maximal supination effort while passively externally rotating the shoulder. A positive test is indicated by discomfort within the shoulder (10). Sensitivity 82.8%, Specificity 81.8% (8). Image from www.mikereinold.com.

Board Style Question:

Which of the following special tests would BEST help you rule in a SLAP lesion?

1. Adson's Maneuver

2. Active Compression Test

3. Sulcus Sign Test

4. Neer's Test

A 22-year-old baseball player presents to the clinic with insidious onset of posterior shoulder pain. Upon examination, he has a positive active compression test, speed's test, Hawkin's Kennedy test, load and rotation test, but negative apprehension test and lateral jobe test. He complains of a deep ache in the shoulder with progressive weakness, clicking, snapping, and increased pain when he pitches. Which of the following diagnosis BEST represents this patient?

1. Type I SLAP lesion

2. Posterior Internal Impingement

3. Type II SLAP lesion

4. Rotator Cuff Tear

Answers:

1. The Active Compression test would be the best option to help you rule in a SLAP tear. However, keep in mind that only one test is not good enough. The literature shows that multiple tests in combination will improve PT diagnosis. Adson's maneuver is a test for thoracic outlet syndrome, the sulcus sign is a test of shoulder instability and Neer's sign is for shoulder impingement. Active compression has 98.5% specificity for SLAP tears, which will help with ruling it in.

2. Type II SlAP lesion would be the best option here. Type II SLAP lesions are the most common type of SLAP lesion and the key indicators in the information given were the patient's age, sport, special test results, and his pain descriptors. Type I would be ruled out due to the fact that it is fraying of the labrum without biceps involvement. The progressive weakness and special tests involving the biceps could help you rule this answer out. Posterior internal impingement also occurs in overhead athletes where the humeral head translates anteriorly causing compression of the supraspinatus and infraspinatus tendons on the posterior side. The apprehension test would have helped determine if there is any anterior instability present that is causing discomfort in the posterior shoulder. RTC can be ruled out in this case due to his pain descriptors. RTC would have greater anterior-lateral shoulder pain that goes down the upper arm. A patient with a RTC tear will typically have tenderness over the greater tuberosity, anterior portion over the acromion, and the lateral jobe test would have most likely been positive.

References:

1. https://www.elpasochiropractorblog.com/2016/11/the-different-types-of-slap-lesions-and.html?m=1

2. Snyder SJ, Karzel RP, Del Pizzo W, Ferkel RD, Friedman MJ. SLAP lesions of the shoulder. Arthroscopy. 1990;6(4):274-9. doi: 10.1016/0749-8063(90)90056-j. PMID: 2264894.

3. Varacallo M, Tapscott DC, Mair SD. Superior Labrum Anterior Posterior Lesions. [Updated 2021 Feb 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538284/

4. Manske, R., & Prohaska, D. (2010). Superior labrum anterior to posterior (SLAP) rehabilitation in the overhead athlete. Physical therapy in sport: official journal of the Association of Chartered Physiotherapists in Sports Medicine, 11 4, 110-21 .

5. Magee, Orthopedic Physical Assessment, 6thedition, 2015.

6. DessaurWA, Magarey ME. Diagnostic accuracy of clinical tests for superior labral anterior posterior lesions: a systematic review. J OrthopSports PhysTher. 2008 Jun;38(6):341-52.

7. Hegedus EJ, Goode AP, Cook CE, Michener L, Myer CA, Myer DM, Wright AA. Which physical examination tests provide clinicians with the most value when examining the shoulder? Update of a systematic review with meta-analysis of individual tests. Br J Sports Med. 2012 Nov;46(14):964-78.

8. Myers TH, Zemanovic JR, Andrews JR. The resisted supination external rotation test: a new test for the diagnosis of superior labral anterior posterior lesions. Am J Sports Med. 2005 Sep;33(9):1315-20. doi: 10.1177/0363546504273050. Epub 2005 Jul 7. PMID: 16002494.

9. Kim SH, Park JS, JeongWK, Shin SK. The Kim test: a novel test for posteroinferior labral lesion of the shoulder--a comparison to the jerk test. Am J Sports Med. 2005 Aug;33(8):1188-92. Epub2005 Jul 6.

10. https://mikereinold.com/clinical-examination-of-superior-labral/