Diagnosis and treatment tips from a veteran arthroscopic surgeon
Superior labral anterior posterior (SLAP) tears can cause significant dysfunction in the overhead throwing athlete but can also be difficult to diagnosis, according to Stephen S. Burkhart, MD.
Once an accurate diagnosis has been made, however, arthroscopic repair of the SLAP tear can produce excellent results—returning a high percentage of pitchers to their preinjury level of performance.
Causes of SLAP lesions
The symptoms of a SLAP lesion may develop suddenly or over a protracted period. The overhead throwing athlete may experience pain during throwing activities or a decrease in pitching velocity. The combination of pain and decreased velocity is known as dead arm syndrome.
SLAP tears were once thought to occur during the deceleration phase of the pitch. New research, however, now indicates that acceleration during the late cocking phase of throwing causes SLAP tears (Fig. 1).
“When the shoulder is in maximum abduction and external rotation, the peel-back and shear forces are maximized, increasing the chances of a SLAP lesion,” Dr. Burkhart explained. “Shoulders with tight posteroinferior capsules are particularly at risk.”
Relationship to rotator cuff tears
Another related injury is hyperexternal rotation and its impact on the rotator cuff. The increased torsional forces on the rotator cuff cause fiber failure. Partial and full rotator cuff tears have been associated with up to 40 percent of SLAP lesions in overhead athletes.
If the tear is less than 50 percent of the thickness of the rotator cuff, Dr. Burkhart recommends débridement. If the tear is greater than 50 percent, he would consider repairing it, although he adds a word of caution.
“Repairing a rotator cuff in a pitcher does not produce nearly the positive results as it does in a nonathletic patient. I’m much more likely to do a débridement if the tear is borderline than to do a repair,” he stated.
Classifying SLAP tears
Categorizing SLAP depends on the “morphology of the tear and the involvement of the long head of the biceps anchor to the superior labrum,” according to Dr. Burkhart.
Throwing athletes most frequently sustain type II SLAP tears. “These lesions occur when the superior labrum detaches medially from the glenoid bone—leaving the superior glenoid neck uncovered for at least 5 mm from the corner of the glenoid,” he explained. This creates a gap between the articular cartilage and the labral attachment into the bone.
Based on the part of the glenoid labrum involved, subtypes of type II SLAP tears are further classified into anterior, posterior and combined anterior-posterior types (Fig. 2).
Diagnosing SLAP lesions
Though tests during a physical examination may be used to diagnose SLAP lesions, their findings are not always consistent with arthroscopic findings.
“Diagnostic tests place either a tensile or torsional load on the biceps—stressing the loose anchor of the biceps-superior labrum complex,” Dr. Burkhart said. This stress will elicit pain in those patients with a type II SLAP lesion.
The Jobe relocation test is the most reliable for diagnosing posterior type II SLAP lesions. When the shoulder is drawn into a position of combined abduction and external rotation, it will cause posterosuperior shoulder pain. Pain and apprehension from posterior and anterior type II SLAP lesions will be relieved by “posteriorly directed force applied to the proximal humerus,” noted Dr. Burkhart.
Although other diagnostic tools—such as radiographs, computerized tomographic arthrography, and magnetic resonance imaging—are frequently used, the results are not considered reliable enough to make a definitive diagnosis of a SLAP tear.
Making a definitive diagnosis
“Definitive diagnosis of SLAP lesions requires arthroscopy with direct visualization, probing, and dynamic testing of the peel-back sign,” Dr. Burkhart said.
“Posterior and combined anterior-posterior type II SLAP lesions will have a positive peel-back sign,” he explained. “The entire superior labrum-biceps complex will shift medially as the arm is externally rotated (Fig. 3).”
Anterior and combined anterior-posterior type II SLAP lesions can be identified by a displaceable biceps root. Placing a probe under the root will demonstrate displacement.
“A final arthroscopic finding in virtually all type II SLAP lesions is a positive drive-through sign, which means that the surgeon can easily move the arthroscope through the glenohumeral joint from superior to inferior,” he added.
Nonsurgical treatment of SLAP lesions
Initially, SLAP lesions should be treated conservatively with anti-inflammatory medication, rest, and stretching exercises.
Dr. Burkhart points out that many throwing athletes will have a tight posteroinferior capsule, which can be demonstrated by scapular winging when patients are in a prone position with their hands on their hips.
This tight posteroinferior capsule causes a glenohumeral internal rotation deficit. Patients with this condition are “truly at risk and require a vigorous stretching program aimed at the posteroinferior capsule.”
If 3 months of conservative treatment do not eliminate symptoms, surgery should be considered.
If the shoulder does not respond to the stretching regimen, Dr. Burkhart will release the posterior band of the inferior glenohumeral ligament surgically—enabling the mechanics to return to normal.
“The goal of surgery is to reestablish a firm bone attachment of the superior labrum-biceps complex and to eliminate the peel-back
and drive-through signs,” he explained.
SLAP lesions should be repaired arthroscopically because, “these lesions are very difficult to approach and visualize by open surgery.”
Dr. Burkhart offers the following “pearls” based on his experience in repairing SLAP lesions in overhead athletes:
- For best results, use suture anchors. Dr. Burkhart prefers polylactic acid biodegradable anchors.
- The most important suture in the SLAP repair is the suture loop placed posterior to the biceps at the corner of the glenoid to resist torsional peel-back.
- A successful SLAP lesion repair will eliminate the peel-back.
The results of SLAP lesion repair are reported to be more than 85 percent good and excellent in returning overhead athletes to their prior level of competition for two seasons or more.
Dr. Burkhart receives inventor royalties from Arthrex.
Annie Hayashi is the senior science writer for AAOS Now. She can be reached at firstname.lastname@example.org