A Superior Labrum Anterior to Posterior (SLAP) tear is an injury affecting the fibrocartilage rim, known as the labrum, that encircles the shoulder socket. This tissue deepens the socket and provides stability to the glenohumeral joint. SLAP tears are categorized by the injury pattern to the superior labrum, where the long head of the biceps tendon attaches. The Type 2 SLAP tear is the most frequently encountered variety, guiding both diagnosis and treatment.
The Anatomy of a Type 2 Tear
The defining feature of a Type 2 SLAP tear is the complete detachment of the superior labrum and the anchor point of the long head of the biceps tendon from the glenoid bone. The labrum is pulled away from the superior rim of the shoulder socket. This detachment creates a gap between the articular cartilage and the unstable labrum-biceps complex.
The superior labrum is the region most loosely attached to the bone, making it susceptible to injury. This tearing runs from the front (anterior) to the back (posterior) of the superior labrum, which is the origin of the acronym SLAP. The involvement of the biceps tendon anchor distinguishes the Type 2 tear from Type 1, which only involves labral fraying with an intact anchor. Type 2 tears can be subclassified based on whether the detachment is primarily anterior, posterior, or a combination of both areas.
Recognizing the Symptoms
Patients with a Type 2 SLAP tear commonly report a vague, deep, and dull ache within the shoulder joint. This pain is often felt most intensely with specific movements, particularly when lifting the arm overhead or stretching the arm behind the head. For overhead athletes, a noticeable loss of throwing velocity or control, sometimes described as a “dead arm” feeling, is a frequent complaint.
A significant sign of this injury is the presence of mechanical symptoms. Patients may experience clicking, popping, catching, or grinding when moving the shoulder. These sensations are caused by the detached and unstable labral tissue getting caught within the joint space. Since the biceps tendon is involved, pain may also be localized to the front of the shoulder, especially with resisted elbow flexion or forearm supination.
Common Causes and Mechanisms of Injury
A Type 2 SLAP tear typically results from two main mechanisms: a single, acute traumatic event or chronic, repetitive stress over time. Acute trauma often involves a forceful compression or traction injury to the shoulder. A common example is falling onto an outstretched arm, which drives the head of the humerus upward against the labrum, causing the tear.
The injury can also be caused by a sudden, powerful pulling force on the arm, such as when attempting to catch a heavy falling object or during a rapid arm deceleration. Chronic overuse is the other frequent cause, especially in athletes who perform repetitive overhead motions (e.g., baseball pitchers, tennis players, or volleyball players). In these athletes, the repetitive motion can lead to a “peel-back” mechanism, where twisting force on the biceps tendon pulls the labral anchor away from the bone.
Methods of Diagnosis
Diagnosing a Type 2 SLAP tear can be difficult because the symptoms often overlap with other shoulder conditions. The initial step involves a detailed physical examination, where the physician assesses range of motion, strength, and stability. Specific provocative tests are performed to reproduce the patient’s pain or mechanical symptoms, which can suggest a labral injury.
Examples of these tests include the Active Compression Test (O’Brien’s test) and the Speed’s test, which place stress on the superior labrum and biceps complex. However, no single physical exam maneuver is completely reliable for confirming a SLAP tear. Imaging is usually required to visualize the soft tissue structures, with Magnetic Resonance Imaging (MRI) being the standard tool.
A Magnetic Resonance Arthrogram (MRA) is often considered the most accurate non-surgical imaging technique for a SLAP tear. This procedure involves injecting a contrast dye directly into the shoulder joint before the MRI scan. The dye flows into the tear and highlights the separation between the labrum and the glenoid. Despite advanced imaging, a definitive diagnosis is often made during diagnostic shoulder arthroscopy, a minimally invasive surgical procedure that allows the surgeon to directly view the tear.
Treatment Options
The treatment approach for a Type 2 SLAP tear is highly individualized, depending on the patient’s age, activity level, and the severity of symptoms. Initial management for most patients begins with non-operative treatment, which may involve rest, activity modification, and the use of non-steroidal anti-inflammatory drugs (NSAIDs) to manage pain and inflammation. Physical therapy is a primary component of conservative care, focusing on strengthening the rotator cuff muscles and the muscles that stabilize the shoulder blade.
If non-operative treatment fails to provide relief after a period of six weeks to three months, surgical intervention may be considered. The choice of surgical procedure often depends heavily on the patient’s age and demands on the shoulder. For younger patients, especially overhead athletes, the goal is often a direct arthroscopic SLAP repair, where the detached labrum and biceps anchor are reattached to the bone using suture anchors.
In contrast, for patients over the age of 40 or those with evidence of biceps tendon degeneration, a biceps tenodesis or tenotomy is often favored. A biceps tenodesis involves cutting the long head of the biceps tendon from its attachment point on the labrum and reattaching it to the upper arm bone (humerus). A tenotomy simply involves cutting the tendon without reattaching it, reserved for older, lower-demand individuals. This shift away from primary repair in older patients is due to more reliable outcomes with biceps-altering procedures in that demographic.