The shoulder is a highly mobile ball-and-socket joint, granting the arm an extensive range of motion. This mobility means the socket, called the glenoid, is shallow compared to the ball (the head of the humerus, or upper arm bone). The labrum is a piece of dense, rubbery fibrocartilage that lines the rim of this shallow glenoid socket, effectively deepening it by up to 50%. This anatomical structure functions as a stabilizing bumper, helping to keep the humeral head securely positioned within the glenoid cavity. A labrum tear is damage to this stabilizing ring of cartilage, which compromises the overall stability and function of the shoulder joint.
Understanding the Shoulder Labrum and Tear Types
The primary role of the labrum is to enhance the shoulder’s stability, acting like a gasket to create a tighter fit for the ball in the socket. By deepening the glenoid cavity, the fibrocartilage ring increases the surface area of contact. The labrum also serves as the attachment point for several important structures, including the glenohumeral ligaments and the long head of the biceps tendon.
Tears are generally classified based on their location, but two types are most commonly identified. A Bankart tear involves the lower front portion of the labrum, typically occurring when the shoulder dislocates anteriorly. This type of tear is frequently seen in younger individuals and athletes involved in high-impact activities, and it can result in recurring shoulder instability.
The Superior Labrum Anterior to Posterior (SLAP) tear occurs in the upper part of the labrum. This tear is significant because it involves the area where the biceps tendon attaches. Damage here often causes pain with activities that engage the biceps muscle or require an overhead motion.
Mechanisms of Injury and Recognizing Symptoms
A labrum tear can result from a single traumatic event or from chronic, repetitive stress. Acute trauma often involves a forceful movement, such as falling onto an outstretched arm, which can drive the humerus into the labrum. A sudden, strong pull or yanking motion on the arm can also cause a tear by placing excessive tension on the biceps tendon and its labral attachment.
Repetitive overhead motions are a frequent cause of SLAP tears, especially in athletes participating in throwing sports, weightlifting, or swimming. Over time, these repeated stresses can fray the labrum, leading to a chronic injury. In older adults, tears can also develop due to age-related degeneration and wear on the cartilage.
Symptoms often include a deep, aching pain inside the shoulder joint that worsens with overhead activities or lifting. A defining symptom is a mechanical sensation when the shoulder moves, such as clicking, popping, grinding, or catching. Patients may also report a feeling of instability, where the shoulder feels loose or as if it might “give way.” Weakness and a limited range of motion can accompany the pain.
Confirming the Injury Through Diagnosis
The diagnostic process begins with a detailed physical examination, where a healthcare provider assesses the shoulder’s range of motion and stability. Specific maneuvers, known as provocative tests, are performed to reproduce the patient’s symptoms, helping to isolate the source of the pain to the labrum. For example, the O’Brien’s test or apprehension tests may be used.
Imaging is necessary to confirm the diagnosis and determine the tear’s exact location and severity. Standard X-rays are typically ordered first to rule out any associated bone fractures or arthritis. However, the labrum itself is soft tissue and is best visualized using magnetic resonance imaging (MRI).
To obtain the clearest possible view of the tear, an MR Arthrogram is often performed. This involves injecting a contrast dye directly into the joint space prior to the MRI scan. The dye fills the joint and outlines the labrum, making any tear or detachment from the bone significantly more visible on the images.
Non-Surgical and Surgical Treatment Options
Treatment for a labrum tear depends on the type and severity of the injury, as well as the patient’s activity level and age. For less severe tears, or those caused by overuse without major instability, conservative, non-surgical management is the initial approach, involving rest and activity modification.
Anti-inflammatory medications (NSAIDs) may be used to manage pain and reduce inflammation. Physical therapy is a primary component of non-surgical treatment, focusing on strengthening the rotator cuff and the muscles that stabilize the shoulder blade. This strengthening improves dynamic stability, which can help compensate for the damaged labrum.
If conservative treatment fails after six to twelve weeks, or if the tear is large and causes significant instability, surgery may be necessary. Most labral procedures are performed arthroscopically, using small instruments and a camera inserted through minor incisions. The two main surgical options are debridement (smoothing frayed edges) and repair (reattaching the torn labrum to the glenoid bone using specialized sutures or anchors).
A Bankart tear causing instability is commonly treated with a repair. A SLAP tear may require a repair or a procedure called biceps tenodesis, which involves detaching the biceps tendon from the labrum and reattaching it elsewhere on the humerus. Recovery requires a lengthy period of rehabilitation and a structured physical therapy program to restore strength and full range of motion. Full recovery, especially for athletes, can take several months.