A superior labral anterior to posterior injury, commonly called SLAP tear, refers to the fraying or tearing of the labrum, a rim of fibrous cartilaginous tissue that surrounds the shoulder socket cavity.
SLAP tears are a complex, painful, and debilitating condition. It is most common in people with physically demanding jobs and athletes who play sports that require overhead arm movements.
SLAP tears are initially managed using a conservative approach involving rest, icing, physical therapy, and steroid injections. Surgery is recommended for severe SLAP tears or if the non-surgical approach fails.
In This Article:
- SLAP Tear Shoulder Injury and Treatment
- SLAP Tear Symptoms
- Labrum Tear Treatments
- Surgery for SLAP Tear Injury
Understanding SLAP tears
The labrum is a thick ring of fibrous cartilage that lines the socket of the shoulder joint.
There are 3 anatomic components involved in a SLAP tear:
- The top part of the upper arm bone (humerus), also called the “ball” or humeral head
- The shoulder socket, also called the glenoid cavity, is a shallow cavity that cradles the ball of the humerus
- The labrum, a layer of fibrous cartilage that surrounds the shoulder socket and provides depth and increased surface area to this cavity
The labrum attaches firmly to the lower portion of the socket but is loosely attached to its upper (superior) portion – the region where a SLAP tear occurs. The tears extend from the front (anterior) to the back (posterior).
Some cases of SLAP tears also involve a tear in the biceps tendon (the tendon that attaches the biceps muscle to the labrum).
See Soft Tissues of the Shoulder
Around 88% of SLAP injuries are also accompanied by other shoulder injuries, such as rotator cuff tears and shoulder impingement.
4 Types of SLAP Tears
Depending on the degree of the tear and involvement of the biceps tendon, SLAP tears are categorized into 4 types,,:
- Type I SLAP tears are characterized by the fraying of the labrum without its detachment from the shoulder socket. Type 1 tears are caused by the gradual degeneration of the labrum with aging or repetitive overhead movements. Fraying of the labrum is common in middle-aged and older individuals.
- Type II SLAP tears involve the detachment of the labrum and the biceps tendon from the shoulder socket. Type II SLAP tears are also caused by either repetitive overhead movements or acute injuries.
- Type III SLAP tears are described as bucket-handle tears, which refer to a crescent-shaped tearing or fraying of the labrum. A type III tear does not involve the biceps tendon. This type of injury is rare and typically observed after a fall on an outstretched arm.
- Type IV SLAP tears are bucket-handle tears accompanied by detachment of the labrum and biceps tendon. Type IV tears are also observed after a fall on the outstretched arm.
Type II SLAP tears are the most common and account for 55% of SLAP tears.
Hallmark Symptoms and Signs of SLAP Tears
SLAP tears cause shoulder pain and/or locking sensations during shoulder movement.
The most prominent symptoms of an acute SLAP tear injury include some combination of the following:
- Deep pain in the shoulder joint while performing arm movements
- A sensation of catching or locking in the shoulder joint when moving the arm
- A clicking or popping sound in the shoulder joint
There’s usually a history of sudden, jerking force to the shoulder prior to an acute SLAP injury.
If a SLAP injury is accompanied by a biceps tendon injury, additional symptoms are experienced, which include:
- Radiating pain in the arm on the affected side
- Pain at rest and during nighttime
SLAP injuries involving the complete rupture of the biceps tendon are associated with a bulge in the biceps muscle near the elbow.
SLAP Tear Causes
Acute traumatic injury or attritional damage to the labrum are the most common causes of SLAP injury.
Acute injury
There are 2 ways a traumatic injury causes labral tear:
- A fall on an outstretched arm exerts compressive force on the head of the humerus and pushes it upwards, causing a tear in the labrum.
- An unexpected pulling force (traction) is applied to the arm, such as hanging onto the step (rung) of a ladder while falling from it or lifting a heavy weight.
Some SLAP tears are also caused by a combination of compressive and pulling forces.
Attritional injury
Repetitive microtrauma of the labrum is common in overhead athletes and middle-aged individuals involved in physically demanding jobs.
Peel-back mechanism
During the cocking phase of throwing (pulling the arm back and rotating the shoulder backward), the biceps twist and strain the labrum, leading to its peeling. This type of labral detachment is referred to as the ‘peel-back mechanism.
Asymptomatic labrum tears
In some individuals, small tears in the labrum do not produce noticeable symptoms.
Studies show that asymptomatic, painless labrum tears occur in some individuals over 45 years old.
Risk Factors for SLAP Injuries
Aging and overhead activities are two major risk factors for SLAP injuries.
Athletes aged 20 to 29 years and middle-aged individuals aged 40 to 49, particularly those involved in physical labor, are at the highest risk for SLAP injuries.
The Course of Shoulder Labrum Tears
Symptomatic SLAP tears typically require medical treatment and have the potential to cause chronic pain and limited mobility.
The recovery period for SLAP tears varies based on factors such as the severity of the tear, accompanying injuries, and the treatment approach.
Individuals with a SLAP tear are at an increased risk of shoulder osteoarthritis in the long term.
How long SLAP tears last
When treated non-surgically, SLAP injuries typically heal in 3 to 6 months.
If surgical intervention is needed, it usually takes 6 to 9 months for complete recovery.
When surgery is needed for SLAP tear injury
Surgical treatment is considered for individuals who do not respond to non-surgical treatment and/or have progressive worsening of symptoms and signs.
A study analyzing data collected between 2003- 2013 estimated that 62.8% of individuals with a SLAP tear need surgical treatment.
For SLAP tears that are accompanied by other shoulder injuries, such as rotator cuff tears, surgical repair of the damaged muscles usually restores normal shoulder function.
When Labrum Tears Are Serious
Severe shoulder numbness and weakness warrant immediate medical attention.
A SLAP tear injury is usually not considered a medical emergency but warrants urgent medical attention in some cases, such as:
- Severe shoulder pain and limited mobility after an acute injury, such as a fall or accident
- Bruising, swelling, and deformity of the shoulder
- Numbness, tingling, or weakness in the shoulder
- Fever accompanied by pain and redness in the shoulder region
These symptoms typically indicate a fracture, dislocation, nerve damage, or infection in the shoulder area.
Early initiation of SLAP tear treatment reduces the necessity of surgery. Resting, icing, and using over-the-counter pain-relieving medications are recommended until the time of a doctor’s visit.
