Introduction 

What is a SLAP tear? 

A SLAP tear is a trauma or an injury that occurs to the labrum of the shoulder. The labrum is a cartilage ring that encircles the socket of the shoulder joint. SLAP is an acronym for Superior Labrum Anterior and Posterior. The upper (superior) portion of the labrum would be injured in a SLAP tear. Additionally, the biceps tendon attaches to the labrum in this area. A SLAP tear occurs both anteriorly (in front) and posteriorly (in back) of this attachment point. In addition, the biceps tendon may be involved in the injury.^1,3

Anatomy of the shoulder

Overview of the shoulder joint

The humerus (upper arm), the scapula (shoulder blade), and the clavicle (collar bone) are the three primary bones of the shoulder. The clavicle extends from the sternum (breastbone) to the acromion (tip of the scapula) and makes two joints –the sternoclavicular (SC) joint and the acromioclavicular (AC) joint. The scapula is located on the back of the ribcage. The scapula is triangular in shape and functions as an attachment point for numerous muscles that are required for shoulder movement.² 

The glenoid fossa, or “socket” of the glenohumeral joint, is located at the lateral or the outer edge. Along the midpoint of the scapula runs the scapular spine, which terminates along the top and front of the shoulder with a projection called acromion. The acromion is the “roof” or “arch” above the glenohumeral joint. In some texts, it may be referred to as “an arch”. It has a protective function (it shields the humeral head and joint space ) and serves as an attachment point for several muscles that act on the scapula and the glenohumeral joint. 

The humerus is the bone of the upper arm. The humeral head is considered to be the “ball” part of the glenohumeral joint and meets the concave glenoid fossa just below the acromion.

In addition to these three bones, it is crucial to note that the ribcage, thoracic vertebrae, cervical vertebrae, and pelvis act on the shoulder using muscular and fascial attachment. If any of the above-mentioned bones and joints are not moving properly or are found to be injured, the complex movements of the shoulder begin to weaken. 

The four joints of the shoulder

The glenohumeral joint 

The glenohumeral joint is formed when the articulating surface of the scapula, known as the glenoid, and the head of the humerus meet. It is considered to be a true synovial joint, and the articular cartilage encompasses the head of the humerus and the face of the glenoid, providing cushioning and a smooth surface for joint movement. As the humeral head is significantly larger than the glenoid, the arm has considerable ability to move but is naturally unstable. This cartilage facilitates movement and safeguards joint surfaces. As with any joint, the glenohumeral (GH) joint is prone to injury and “wear and tear”. 

The sternoclavicular joint 

The sternoclavicular joint consists of the clavicle and its attachment to the sternum. It is a synovial joint with a fibrocartilage disc to enhance congruency between the bones. This joint is exceptionally sturdy, with ligamentous support that prevents dislocation. The sternoclavicular joint serves the following purposes:  

• The sternoclavicular joint anchors the clavicle and the shoulder girdle to the torso
• It acts as a pivot point at which the clavicle moves to enable movement of the shoulder complex. 

The acromioclavicular joint

The acromioclavicular joint originates from the intersection of the lateral edge of the clavicle and the acromion process of the scapula. It is considered to be a synovial joint.

The main functions of the acromioclavicular joint: 

• The acromioclavicular joint enables the scapula additional rotational range on the scapula
• It permits modifications to the scapula’s position so that it can follow the movement of the torso and rib cage
• Allows for the transmission of forces from the upper extremity to the clavicle

The scapulothoracic joint

The scapulothoracic joint is not a true synovial joint, nevertheless, it is a complex connection that is necessary with all shoulder movements. It depends upon the integrity of the acromioclavicular and sternoclavicular joints. For the shoulder to remain movable, stable, and healthy, all four joints must move in perfect synchronisation.

Structures in the shoulder joint

Glenoid labrum

The glenoid labrum is a fibrocartilaginous structure that connects as a rim to the glenoid fossa’s articular cartilage. Its function is to deepen and raise the surface area of the glenoid, resist anterior and posterior movement, and aid in preventing shoulder dislocation and subluxation at maximum levels of movement.

Biceps tendon

The biceps tendons are located in front of your upper arm. It is attached to the shoulder and elbow by tendons, which are strong chords of fibrous tissues that connect muscle to bones.

Rotator cuff

The rotator cuff provides strength and stability during shoulder movement

Types of SLAP tear

SLAP tears are classified into four main types:⁴

• Type 1: In this type, your labrum will exhibit evidence of fraying yet continue to function. Typically, middle-aged or elderly individuals exhibit type 1 SLAP tear.
• Type 2: This is the most prevalent SLAP tear type. The labrum and bicep tendon are separated from the shoulder socket in type 2 SLAP tear.
• Type 3: In type 3 the labrum tissues are entrapped in the shoulder joint
• Type 4: The tear that begins in your labrum and damages your bicep tendon is this type

Causes

• Chronic injury: Over time, athletes who participate in repetitive overhead sports such as baseball and softball are susceptible to developing SLAP injuries. The labrum gradually breaks down because of repeated actions. As a result, a SLAP tear may occur.
• Acute injury: This type of injury may be caused by an abrupt or acute trauma. One such example is vigorously tugging on the arm or rapidly moving the arm when it is above shoulder level.
• Ageing: Tearing of the labrum can develop as a part of general ageing and is not uncommon in persons over 40 years old ^3,5

Symptoms

Typical symptoms of this type of tear include:⁵ 

• Shoulder discomfort when moving the arms
• Pain when moving or lifting heavy objects
• Reduced capacity to perform sports
• Shoulder joint clicking as if something were trapped inside
• Intense pain within or behind the joint
• Pain in the shoulder’s front

Diagnosis 

Physical examination

• Neck Examination: An assessment should be conducted on the neck posture, muscular symmetry, palpable tenderness, and active/passive range of motion
• Shoulder Examination: The examiners must observe and compare bilateral shoulder girdles to identify asymmetry, scapular posturing, and atrophic changes. It is imperative to visually inspect the skin for indications of prior surgical incisions, lacerations, and scars³ 
• Provocative examination testing/manoeuvre: A combination of specific tests, which includes tests like  ‘Speed test’ and ‘Uppercut test’ are recommended to detect biceps tendon lesions clinically.

Imaging techniques  

• Radiographs: An x-ray of the glenohumeral joint should be acquired by the clinicians 
• MRI: MRIs are frequently employed to identify SLAP lesions. In addition to arm traction and external rotation, contrast media enhances the sensitivity of the MRI when identifying SLAP lesions⁵

Treatment 

Anti-inflammatory medications, cryotherapy/cooling/ice application, rest, and activity modification 

After experiencing an acute injury, it is recommended that all patients undergo an initial phase of recuperation. NSAIDS and the administration of a cryotherapy device or ice compress may be advantageous in managing pain. In addition, a restricted sport-specific timeline protocol should be implemented for overhead athletes, while manual labourers should be provided with suitable occupational modifications.

Physical therapy 

Physical therapy is used to treat any underlying pathologic shoulder biomechanics that were present before the acute injury. Additionally shoulder girdle proprioceptive training aids in the prevention of recurrence. If physical therapy fails and the symptoms persist that prevent the activities of daily living, surgery may be necessary.

Surgical management

Surgical treatments are proposed depending on the type of SLAP tear. Determining whether the patient’s symptoms are solely attributable to the labrum or if restoring the labral attachment and biceps root to the glenoid will be beneficial is of the utmost importance.^6,7

Complications of surgical treatment

• Infection
• Excessive amount of bleeding
• Blood vessel and nerve damage within the shoulder joint
• Recurrent instability of the shoulder
• Shoulder rigidity⁸

Summary 

SLAP, short for Superior Labrum Anterior Posterior Tear, refers to a distinct category of shoulder trauma wherein the labrum, a cartilaginous ring encircling the shoulder socket is compromised. Traumatic incidents, or the natural process of ageing frequently give rise to SLAP tears which manifest in a variety of symptoms including shoulder discomfort, instability, and reduced range of motion.  

SLAP injuries are frequently observed in individuals participating in overhead sports and in those who experience repetitive shoulder strain. To restore shoulder function, precise diagnoses and treatment are essential.