Adhesive capsulitis, or frozen shoulder, is a condition that occurs when scar tissue forms within the shoulder. This causes the shoulder capsule to thicken and tighten around the shoulder joint and reduces the amount of space for the shoulder to move within. Although frozen shoulder affects up to 5% of the population, it is not yet clear why it develops. Common consensus suggests that one of the leading factors is not moving the shoulder normally for long periods of time, as most people who get frozen shoulder have kept their shoulder immobilized due to a recent injury, surgery, or pain. It is most likely to develop between the ages of 40–60, and patients with arthritis, diabetes, cardiovascular disease, and other health conditions are also more likely to have the condition.

Frozen shoulder usually comes on slowly and gets progressively worse over time with more pain and loss of motion. It is typically divided into four stages, with the onset of symptoms occurring in Stage 1 over 1–3 months, and symptoms resolving by Stage 4—the “thawing” stage—which occurs within 12–15 months of onset. Physical therapy is commonly recommended for frozen shoulder, as research consistently shows that it provides numerous benefits at every stage; however, there is a lack of consensus about which interventions are most effective. Therefore, a powerful study called a systematic review and meta–analysis was conducted with two goals: 1) compare the effectiveness of exercise alone versus exercise with other interventions, and 2) compare the different methods of exercise to determine which were most effective.

Exercise improves various symptoms, but value of other interventions is unclear

Researchers performed a search of three major databases to identify high–quality studies that evaluated the effectiveness of exercise therapy and other interventions for patients with frozen shoulder. This search led to 33 studies being included in the systematic review and 19 being included in the meta–analysis. The most common types of exercises featured in these studies were strengthening exercises, stretching and range of motion exercises, muscle energy techniques, and pendulum exercises, while non–exercise–based therapies included manual therapy, ultrasound, and heat therapy, among others.

Results showed that exercise therapy was effective for reducing pain and improving range of motion and physical function in patients with frozen shoulder. In the analysis of eight studies that compared exercise therapy to multimodal programs—which involve a variety of interventions—little or no evidence was found that these multimodal programs were superior to exercise–only programs in improving range of motion, disability, or pain. In addition, multimodal programs that involved exercise were found to be more effective than multimodal programs that did not involve exercise, and two studies found that adding stretches to a multimodal program involving exercises may increase range of motion.

These findings confirm that exercise therapy is indeed an effective intervention for frozen shoulder, but adding passive modalities does not appear to offer any additional benefit to exercise treatment programs. More research is therefore needed on the relative effectiveness of various nonsurgical interventions for frozen shoulder, but in the meantime, patients are encouraged to continue seeing a physical therapist, where they can count on receiving an exercise–based and highly personalized treatment program.