The supraspinatus tendon is a functionally significant part of the rotator cuff, a group of four tendons and muscles that stabilize the shoulder joint and facilitate arm movement. It is the most frequently injured component, often leading to shoulder pain and limited function. Supraspinatus tears are common, with prevalence increasing significantly with age, and the potential for healing depends largely on the injury’s characteristics and the body’s biological response.
The Biology of Tendon Repair and Tear Classification
Tendons have a limited blood supply compared to muscles, which naturally slows the delivery of necessary healing factors and cells. Healing is further complicated in the supraspinatus tendon because the area beneath the acromion bone, where the tendon passes, is particularly susceptible to poor circulation.
Tears are categorized into two types: partial-thickness tears (PTTs) and full-thickness tears (FTTs). A partial-thickness tear means the tendon is damaged or frayed but remains connected to the bone, involving only a portion of the tendon’s width. These tears have significant potential for self-repair and remodeling because a bridge of healthy tissue remains intact, allowing for structural continuity.
In contrast, a full-thickness tear involves a complete separation of the tendon from its attachment point on the humerus. Full-thickness tears typically do not heal without surgical intervention because the muscle pulls the torn edges apart, preventing the necessary tissue bridge from forming. These tears exhibit a reduced regenerative capacity compared to partial tears due to the progression of muscle changes and atrophy.
The severity of a partial tear is often graded by the percentage of the tendon’s thickness that is affected. Tears involving less than 50% of the tendon’s thickness are considered low-grade, while tears greater than 50% are high-grade. Although low-grade PTTs have the greatest chance for healing, even these tears can progress to full-thickness injuries over time without proper management.
Maximizing Non-Surgical Healing Potential
For many partial-thickness tears, and some small full-thickness tears, the body’s healing capacity can be supported through conservative management. Non-surgical care focuses on reducing symptoms and improving the function of the surrounding shoulder musculature. This approach is effective in relieving pain and restoring function for a large percentage of patients, often eliminating the need for surgery.
Targeted physical therapy (PT) is the most important component of non-surgical treatment, acting as an organized intervention to guide the healing process. PT involves specific exercises aimed at strengthening the remaining rotator cuff muscles, particularly the infraspinatus and subscapularis, to compensate for the injured supraspinatus. Strengthening the muscles that stabilize the shoulder blade, known as the scapular stabilizers, is also a primary focus to improve overall shoulder mechanics.
Pain management and activity modification are necessary adjuncts that allow the patient to participate in rehabilitation effectively. Rest and avoiding repetitive overhead movements are essential to prevent further strain on the healing tendon. Nonsteroidal anti-inflammatory drugs (NSAIDs) may be used temporarily to reduce inflammation and pain, facilitating participation in physical therapy.
Injections may be used to manage symptoms, though they do not directly repair the tear itself. Corticosteroid injections provide short-term pain relief by reducing local inflammation, which can be beneficial for starting physical therapy. Regenerative options like Platelet-Rich Plasma (PRP) or bone marrow aspirate concentrate (BMAC) use the patient’s own cells to introduce growth factors that may promote a healing environment.
When Self-Healing Isn’t Enough: Criteria for Surgery
While conservative treatment is often successful, certain tear characteristics indicate that the tendon’s self-healing potential will be insufficient. Continued pain that fails to improve after 3 to 6 months of non-operative treatment is a primary indicator for considering surgery.
The size of the tear is a major factor, with larger tears being less likely to heal on their own. Full-thickness tears, particularly those greater than 3 centimeters, often require surgical repair because the torn tendon end has retracted significantly from the bone. This retraction prevents the two ends from coming close enough for biological healing to occur.
Significant loss of shoulder function or strength, where the patient cannot actively lift or rotate the arm, also warrants surgical intervention. This loss of function is often associated with a complete detachment of the tendon from the bone. For younger, active patients who experience an acute, traumatic full-thickness tear, surgery is frequently recommended sooner to achieve the best long-term outcome.