Overview
Corticosteroid (cortisone) injections are one of the most common and effective non-operative treatments for shoulder pain. They can be used for a variety of shoulder conditions, including inflammation, impingement, arthritis, frozen shoulder, and selected rotator cuff and biceps problems. Corticosteroid injections reduce inflammation, which is often a major source of pain. Although they do not heal the underlying structural problem, decreasing inflammation can provide significant pain relief and improve shoulder function.
An important part of shoulder injections is placing the medication in the correct location. Depending on the condition, injections may be given into the subacromial space, glenohumeral joint, or AC joint. In many cases, an injection can also provide useful diagnostic information by helping identify the source of the pain.
Cortisone Injections
Most of my corticosteroid injections contain a combination of Depo-Medrol and Kenalog, providing both intermediate- and longer-acting corticosteroid effects. These medications are mixed with a local anesthetic (Lidocaine/Marcaine) to provide immediate temporary pain relief. Corticosteroid injections are relatively inexpensive, require no pre-certification, and can usually be performed during your office visit, allowing treatment to begin immediately.
Immediately after the injection, the local anesthetic typically provides one to two hours of numbness. As the local anesthetic wears off, it is common to experience a few days of mild to moderate soreness before the corticosteroid begins taking effect and providing longer-lasting relief. Cortisone does not heal the underlying problem. Instead, it decreases the inflammation surrounding the problem, and that inflammation is often a major source of the pain. The medication typically remains active for approximately 2-3 months, although many patients continue to experience improvement well beyond that period if the inflammation has been successfully reduced.
Many injections serve both a diagnostic and therapeutic purpose, helping confirm that the injected location is a primary source of pain while also providing relief. Fortunately, shoulder injections are among the least painful injections performed in orthopedics. Because of their tremendous effectiveness and relatively minimal discomfort, many patients return for repeat injections when appropriate.
Safety
Corticosteroid injections are extremely safe and have almost no interactions with other medications. The most common side effect occurs in diabetic patients. Blood sugars may increase significantly for approximately 2-3 days before returning to their normal levels. Although I have safely treated hundreds of diabetic patients over the years, I encourage diabetic patients to monitor their blood sugars carefully and, if necessary, discuss temporary medication adjustments with the physician managing their diabetes.
The risk of infection is extremely low. In nearly 30 years of practice and tens of thousands of injections, I have encountered this complication only once. Although the risk is very small, the consequences can be significant, particularly around prosthetic joints. When surgery is anticipated, I generally prefer to wait approximately 6-8 weeks before arthroscopic surgery and approximately 3 months before shoulder arthroplasty.
Shoulder Cortisone Injections
There are three primary corticosteroid injection locations around the shoulder.
Subacromial Injection: Primarily used for shoulder impingement, subacromial bursitis, and selected rotator cuff disorders.
Glenohumeral Joint Injection: Primarily used for shoulder arthritis, adhesive capsulitis (frozen shoulder), and selected biceps disorders.
AC Joint Injection: Primarily used for degenerative AC joint arthritis.
One important exception involves repairable rotator cuff tears. Recent studies suggest that multiple corticosteroid injections before rotator cuff repair may negatively affect tendon healing. Therefore, I generally limit repeated injections when surgical repair is likely.