A rotator cuff tear (RCT) involves damage to one or more of the four tendons that stabilize the shoulder joint, which is a common source of chronic shoulder pain and functional limitation. When conservative treatments like rest and physical therapy do not provide sufficient relief, a corticosteroid injection, commonly known as a cortisone shot, is often considered a non-surgical option. This procedure delivers a powerful anti-inflammatory medication directly into the shoulder area to manage pain. It is important to understand that this treatment is not a cure for the tear itself but a tool used to manage symptoms and facilitate other forms of rehabilitation.
The Mechanism of Corticosteroid Action
A cortisone shot delivers a synthetic corticosteroid, a potent anti-inflammatory agent, directly to the affected area, often the subacromial space above the rotator cuff tendons. The corticosteroid enters the cells, acting as a transcription factor that changes gene expression. This suppresses the body’s local inflammatory response by inhibiting inflammatory chemicals, such as cytokines and enzymes like COX-2.
By blocking these pathways, the medication reduces the localized swelling and irritation that contribute significantly to the pain experienced with a rotator cuff tear. The shot often includes a local anesthetic, such as lidocaine, which provides immediate, though temporary, pain relief while the corticosteroid begins its anti-inflammatory work, which typically takes a few days. This reduction in inflammation and pain aims to create a window of opportunity for improved function.
Efficacy of Injections for Rotator Cuff Tears
Cortisone shots can provide significant and rapid relief from the pain associated with a rotator cuff tear, often improving shoulder function in the short term. The medication’s effect on pain is generally felt a few days after the injection, once the initial flare of localized discomfort subsides. Studies suggest that the period of moderate pain relief commonly lasts between six weeks and three months, but in some cases, it may extend up to several months.
The effectiveness, however, is purely symptomatic and does not address the underlying structural damage of the tendon. The injection does not repair or heal the tear, and the underlying condition remains once the medication wears off. The degree and duration of relief can vary considerably depending on the specific cause of the pain, the patient’s individual response, and the severity of the tear.
Cortisone shots may be more effective for smaller, partial-thickness tears or inflammation of the bursa surrounding the tendons (bursitis) than for large, full-thickness tears. While the injection can improve a patient’s ability to move their arm, the primary purpose is to temporarily alleviate pain and swelling, enabling the patient to engage in other necessary treatments.
Potential Risks and Limitations of Cortisone Shots
While cortisone shots offer temporary relief, they have potential drawbacks, especially when used repeatedly. Corticosteroids can suppress tenocyte activity and collagen synthesis, processes necessary for tendon health and repair. This can weaken the rotator cuff tendon, increasing its susceptibility to further damage or rupture. Some research indicates that an injection may be associated with an increased risk of future cuff tendon tears, with one study suggesting an elevated risk by over seven times compared to non-injection groups.
Repeated injections are limited because the negative effects on tendon integrity are cumulative and dose-dependent. Clinicians typically restrict the frequency of injections to a maximum of about three per year for any single joint. Other potential side effects include a temporary increase in blood sugar levels, which is a particular concern for diabetic patients. Localized reactions such as fat atrophy (a dimple in the skin) or depigmentation (lightening of the skin at the injection site) are also recognized risks.
Integrating Injections into a Comprehensive Treatment Plan
A cortisone injection is rarely a standalone treatment for a rotator cuff tear; it is a tool used within a broader strategy. The injection’s primary role is to act as a “bridge” by reducing pain and inflammation, making the patient comfortable enough to fully participate in a structured physical therapy (PT) program.
Active participation in PT is crucial for strengthening surrounding muscles and restoring proper shoulder mechanics, the long-term goal of non-surgical management. Without the temporary relief, severe pain might prevent a patient from engaging in necessary rehabilitation exercises. Alternatively, injections may be used as a temporary measure to manage symptoms while a patient is awaiting surgical repair or if they are unable to undergo surgery due to other health factors.
The timing of the injection is also considered carefully, particularly if surgery is a possibility. Studies suggest that receiving a cortisone shot within six months before a rotator cuff repair surgery may increase the risk of the surgical repair failing to heal properly or needing revision surgery. Therefore, the decision to use an injection must be weighed against the patient’s overall treatment timeline and long-term goals.