Many adults (mostly women) between the ages of 40 and 60 years of age develop shoulder pain and stiffness called adhesive capsulitis. Most people are more familiar with the term “frozen shoulder” to describe this condition. But frozen shoulder and adhesive capsulitis are actually two separate conditions. A more accurate way to look at this is to refer to true adhesive capsulitis (affecting the joint capsule) as a primary adhesive capsulitis.
As the name suggests, adhesive capsulitis affects the fibrous ligaments that surround the shoulder forming the capsule. The condition referred to as a frozen shoulder usually doesn’t involve the capsule. Secondary adhesive capsulitis (or true frozen shoulder) might have some joint capsule changes but the shoulder stiffness is really coming from something outside the joint.
Some of the conditions associated with secondary adhesive capsulitis include rotator cuff tears, biceps tendinitis, and arthritis. In either condition, the normally loose parts of the joint capsule stick together. This seriously limits the shoulder’s ability to move, and causes the shoulder to freeze.
Steroid injections are sometimes recommended if and when the patient fails to improve with conservative care such as physical therapy, activity modifications, and antiinflammatory or analgesic (pain relieving) medications. But there is some controversy over the best dosage.
The optimal dose of steroid remains unknown. Currently, there are two different doses that are used most often (20 mg and 40 mg). Triamcinolone acetonide is one of the common corticosteroid choices because of its long-acting effects and relatively low side effects. However, it should be noted that current practice is not based on scientific evidence, but rather, experience, cost, and availability of the drug.
You may be interested in a recent study from South Korea, surgeons from the Ajou University Medical Center propose that a high-dose corticosteroid would perform better than low dose in terms of reducing pain and restoring function. To test their hypothesis, they set up a randomized, triple-blind, placebo-controlled dose-comparative study. Triple blind means that no one (not the patient, not the person injecting the drug, and not the evaluator) knew who was getting what (drug, drug dose, placebo).
There were 53 total patients divided (randomly) into three groups: low-dose corticosteroid (20 mg triamcinolone acetonide), high-dose steroid (40 mg of the same drug), and placebo (saline injection). The two dosages selected were based on current practice by most physicians. Injections were guided using ultrasound for accurate placement of the drug or placebo. Everyone in all three groups was given a 10-minute follow-up exercise program to do three times daily for 12 weeks.
Outcome measures included pain level, range-of-motion, function, and level of disability. All patients were tested before treatment and again after treatment at regular intervals (one week, three weeks, six weeks, and 12 weeks after injection).
There is much concern about using high-dose corticosteroid drugs because of the potential for negative (adverse) effects. Other studies have shown that higher levels of steroid can cause complications and problems. For example, changes in skin coloration, tendon ruptures, nerve lesions, and loss (atrophy) of tissue have been reported. But too low of a dose might not provide the desired change in symptoms, so determining the optimal dose for this particular problem would be very helpful.
Everyone in the study mentioned got better. The two steroid groups had significantly more improvement than the placebo group. But there were no significant differences between the low- and high-dose patients in terms of pain, motion, and function. A few patients experienced some reactions to the drugs (e.g., facial flushing, dizziness) but no one had any infections, skin or soft tissue changes, or other adverse effects.
The authors concluded that a 20-mg dose of steroid injection given early on in the course of adhesive capsulitis is advised. This gives the same benefit as higher dose treatment but with lower risk for local and systemic side effects.
They further commented that this particular drug is a long-acting corticosteroid. Different results might be obtained if using a short-acting steroid. This is also a short-term study and results may change as time goes by. Further follow-up of these patients will be done and outcomes reported at a later date.