Shoulder pain is a common complaint that can severely limit daily activities. When conservative measures like rest, oral medication, and physical therapy are insufficient, injections offer a powerful, non-surgical option for localized relief. Selecting the appropriate treatment requires a professional evaluation of the underlying cause of the pain, as there is no single “best” option. The goal is to deliver medication directly to the source of the discomfort, offering a targeted approach.
How Injections Target Shoulder Pain
Injectable treatments concentrate therapeutic agents precisely where they are needed, minimizing the systemic effects of oral medications. These procedures serve two primary goals: therapeutic benefit and diagnostic clarification. Therapeutic injections deliver substances that reduce inflammation, promote healing, or improve joint function in the affected area.
The diagnostic function is achieved by combining the treatment substance with a local anesthetic. If the pain is immediately relieved following the injection, it confirms that the injected location is the source of the patient’s symptoms. These targeted applications interrupt the cycle of pain and inflammation, creating a window of opportunity for physical therapy and rehabilitation to be more effective.
Major Categories of Injectable Treatments
The substances used in shoulder injections fall into three main categories, each with a distinct composition and mechanism of action.
Corticosteroid injections, often called cortisone shots, contain anti-inflammatory chemicals. These synthetic steroids suppress the immune response, rapidly reducing swelling and pain associated with acute inflammation. Relief typically lasts for several months, but repeated injections are limited due to potential long-term tissue degradation.
Biologics, such as Platelet-Rich Plasma (PRP), are derived from the patient’s own blood. The blood is processed to concentrate platelets, which deliver high levels of growth factors to an injured site. This mechanism focuses on stimulating tissue repair and regeneration, aiming for longer-term healing.
Viscosupplementation injections typically use hyaluronic acid, a substance naturally found in healthy joint fluid. This gel-like material acts as a lubricant and shock absorber, improving the mechanical function of the joint. Primarily used for conditions involving joint wear, this approach aims to restore the protective qualities of the synovial fluid.
Selecting the Optimal Injection Based on Diagnosis
The effectiveness of an injection depends entirely on correctly matching the substance to the specific shoulder pathology.
Soft Tissue Inflammation
For conditions involving soft tissue inflammation, such as rotator cuff tendinopathy or subacromial bursitis, corticosteroids are often the first-line injectable treatment. They provide rapid short-term pain relief by calming the acute inflammatory process in the bursa or tendon sheath.
Chronic Tendon Injuries
For chronic tendon issues or partial rotator cuff tears, where healing is the primary goal, biologics like PRP are often considered. Studies suggest PRP injections may offer superior long-term pain relief and functional improvement compared to corticosteroids in these chronic cases. The growth factors in PRP encourage the structural repair of the damaged tendon tissue.
Osteoarthritis
In cases of osteoarthritis, which involves the breakdown of joint cartilage, viscosupplementation with hyaluronic acid is a common choice. The injection helps to cushion the worn joint surfaces and may also have mild anti-inflammatory effects. Corticosteroid injections can also be used, but their long-term use is not recommended as they may accelerate the progression of joint degeneration.
Adhesive Capsulitis (Frozen Shoulder)
For adhesive capsulitis, or frozen shoulder, an intra-articular corticosteroid injection into the glenohumeral joint is a common treatment, often combined with physical therapy. In some cases, a high-volume injection procedure called hydrodilatation may be performed to stretch the contracted joint capsule. Emerging evidence suggests that PRP and hyaluronic acid injections may offer comparable long-term outcomes for pain and range of motion.
What to Expect During and After the Procedure
Before the procedure, patients may be advised to temporarily stop taking certain medications, such as blood thinners, which must be discussed with the prescribing physician. The injection itself is generally a quick, outpatient procedure performed with the patient seated or lying down. The area is cleaned and a local anesthetic is typically applied to numb the injection site.
To ensure precise delivery of the medication, the injection is often performed using real-time ultrasound guidance or fluoroscopy (a type of X-ray). Imaging guidance increases the accuracy of the injection, which is linked to better clinical outcomes. The entire process of preparation and injection usually takes only a few minutes.
Patients are typically advised to avoid strenuous activity or heavy lifting for 24 to 48 hours afterward to allow the substance to settle. While a small number of patients may experience a temporary increase in pain, known as a “steroid flare,” this usually resolves within a day or two and can be managed with ice and over-the-counter pain relievers. Risks are low but include infection at the injection site and, rarely, allergic reactions.