What is it?
The acronym “SLAP” stands for Superior Labrum Anterior Posterior, and it is used to describe a tear or detachment of the shoulder’s superior glenoid labrum. The tear is usually located at the originating anchor site for the biceps tendon and extends into the anterior or posterior portions of the labrum. This is a very common pathology.
The glenoid labrum is a circle-shaped rim of fibrocartilage that surrounds the entire perimeter of the shoulder joint. The labrum serves as an attachment for tendons and ligaments. At its superior surface, the long head of the bicep tendon converges with the labrum and provides an anchor for approximately 50% of the fibers that form the long head of the bicep tendon.
Labral tears may occur abruptly from injury or develop more slowly from repetitive microtrauma. The forces associated with a labral injury typically include either superior compression or sudden inferior traction. Traumatic onset, including a fall or direct blow to the shoulder, are responsible for almost 1/3 of all SLAP lesions. The most common mechanism of an acute injury involves a fall onto an outstretched arm with the shoulder abducted and flexed forward.
SLAP lesions are common in athletic populations, particularly those requiring overhead motions that encourage the bicep muscle to pull the labrum from its underlying bony attachment.
Chronic SLAP lesions do not typically occur in the absence of concurrent shoulder pathology. For instance only 28% of SLAP tears are isolated problems.
There are four widely accepted classifications for SLAP lesions. Type 1 injuries involve degeneration of the glenoid labrum. Type 2 injuries involve detachment of the glenoid labrum from the bony rim, creating a less stable biceps anchor. Type 3 lesion has progressed into a “buckle handle” displacement of the superior labrum into the glenohumeral joint. Type 4 lesions include all the previous issues mentioned plus at least a partial tear of the long head of the biceps tendon.
Type 1 and 2 lesions make up the vast majority of SLAP tears. Type 3 and 4 lesions are thought to account for less than 10% of SLAP tears and are frequently associated with instability.
A history of trauma or instability increases the likelihood of SLAP lesions. However, there are many cases where patients present without a history of trauma or predisposing activity. A predisposing factor includes throwers due to this motion causing a lot of strain on the bicep tendon and its attachment to the labrum. The occurrence of SLAP tears increases with age.
SLAP lesion complaints can vary from asymptomatic to disabling. Symptomatic patients often describe a deep, vague, non-specific shoulder pain that is provoked by overhead and cross-body activity. Weakness and stiffness are often associated with this disorder. Discomfort may limit athletic performance, especially in overhead athletes who participate in overhead activity.
Patients may complain that popping, clicking, grinding, or catching are common. Patients with SLAP tears may say they feel like they have a “dead arm.” Range of motion deficits are possible, particularly with cross-body adduction and forward flexion.
Throwers may be particularly vulnerable as this activity subjects the bicep tendon and its labral attachment to significant strain. Only 7-57% of elite overhead athletes are able to return to pre-injury level of competition following surgical SLAP tear.
Due to clinical assessments of SLAP tears being difficult to diagnose between different shoulder injuries, imaging is usually the main source of diagnosing this issue. Regular radiographs do not show SLAP lesions but can be used to rule out other possible diagnoses. Diagnostic ultrasound is a useful modality for imaging SLAP tears. MRIs are typically included in the initial workup with patients suspected of labral pathology.
The presence of a SLAP lesion does not automatically necessitate surgical intervention. 2/3 of SLAP lesions will show symptomatic improvement through conservative care focusing on regaining ROM (range of motion), rotator cuff balance, along with hip, core and scapular stability. Recommendations of 6-12 weeks of conservative care prior to surgical intervention. The main goals for conservative care should be to reduce pain, enhance mobility, and restore strength.
Progressive strengthening of the scapula and rotator cuff musculature should be implemented as tolerated. Strengthening exercises should focus on balancing the posterior and anterior muscle groups. Rehabilitation needs to focus on restoring serratus anterior strength and proper scapular function. Clinicians should address regional deficits such as scapular dyskinesis and upper cross syndrome, as well as dysfunction in the hip and core. Flexibility programs are incorporated as symptoms allow.
Myofascial release should focus on subscapularis, infraspinatus (rotator cuff muscles), anterior shoulder muscle groups, and posterior shoulder capsule. Manipulations may be helpful to restore mobility to restricted cervical or thoracic segments.
Early mobility exercises should include wrist and elbow mobility, passive shoulder forward flexion to 90 degrees with assistance, passive shoulder external rotation, and gripping exercises. Strengthening exercises begin with scapular stabilization as well as shoulder isometric internal rotation and external rotation in a pain-free neutral position.
A patient that experiences a traumatic episode and has symptoms of a SLAP lesion, especially instability may need a surgical console. Surgical repair typically involves a four to six month post operative rehab program.