Intra-articular steroid injection may slightly improve pain and function in patients with adhesive capsulitis

Resident Focus - Volume 13, Issue 4

Reference: American Journal of Sports Medicine 2017 Jul;45(9):2171
Level 2 [mid-level] evidence

Adhesive capsulitis, also called frozen shoulder (FS), is a painful, debilitating condition characterized by reduced active and passive range of motion of the shoulder, particularly with external rotation. It commonly affects middle-aged patients, women slightly more than men, and has a prevalence of about 2% (Annals of the Rheumatic Diseases 1984;43:361-364). FS can occur secondary to trauma, surgical intervention, or overuse, but is often idiopathic. Although it is a self-limited disorder that typically lasts between 18-36 months, it causes significant disability during the recovery period. Typical treatments include physical therapy, exercise, and intra-articular steroid injection, though previous meta-analyses have not found steroid injection to be superior to placebo for reducing pain. Should we continue doing steroid injections to reduce pain of FS?

A recent systematic review evaluated the efficacy of a single intra-articular steroid injection compared to placebo injection or no injection for reducing pain associated with FS. The analysis included 8 randomized controlled trials (RCTs) with 416 patients with adhesive capsulitis of the shoulder. All patients were given mobilization and stretching exercises to perform and in some trials both the intervention and control groups were prescribed nonsteroidal anti-inflammatory drugs or analgesics. The primary outcome analyzed was pain reduction on the visual analog scale (VAS) (a 10 point scale with higher numbers meaning worse pain). Secondary outcomes included measures of range of motion and functional scores using the Shoulder Pain and Disability Index (SPADI) (higher score indicates worse pain and function). Results were evaluated at 4-6 weeks, 12-16 weeks, and 24-26 weeks after intervention. Included trials were closely evaluated for inclusion/exclusion criteria, exclusion of additional co-interventions, and bias. Steroid dose and injection approach varied among studies, limiting the validity and precision of the results.

Meta-analysis revealed single intra-articular steroid joint injection reduced pain at all three time points. A 40 mg dose of corticosteroid was used in the majority of studies, but a 20 mg dose did not demonstrate any inferiority in the others. There was a reduction of 1.28 points (95% CI 0.75-1.82 points) in the VAS at 4 weeks, a reduction of 1 point (95% CI 0.47-1.52 points) at 12-16 weeks, and a reduction of 0.65 points (95% CI 0.19-1.1 point) at 24-26 weeks. Shoulder functionality via SPADI score also improved at 4-6 weeks (MD 16.62 points, 95% CI 11.16-22.09), at 12-16 weeks (MD 13.46 points, 95% CI 8.15-18.77) and at 24-26 weeks (MD 9.91 points, 95% CI 2.32-17.5). Although statistically significant, the magnitude of these VAS and SPADI reductions may not make clinical differences to overall patient experience and may not translate to long term functional outcomes. Complications including facial flushing, dizziness, chest or shoulder pain, and nausea were reported in a total of 3.9% of all patients in the sham-controlled trials regardless of placebo vs. steroid grouping.

These results support a small sustained benefit to steroid injection for patients with FS that was not found in a previous meta-analysis (Physiotherapy 2010;96:95-107),which excluded studies with no formal physical therapy component. Intra-articular shoulder injection may slightly improve pain and functionality with minimal serious side effects. Stratifying future analyses by phase and severity of FS may identify the most beneficial timing of steroid injection. Intra-articular steroid injections for FS may reduce pain and improve functional performance, but further studies are needed to evaluate optimal circumstances for this treatment.

For more information, see the Adhesive capsulitis of shoulder topic in Dynamed Plus. DynaMed users, see the Adhesive capsulitis of shoulder topic in Dynamed Classic.

Elizabeth (Lizzy) Carstensen is a third-year resident at the University of Virginia Family Medicine Program. She is originally from Birmingham, Alabama. She completed her undergraduate training at Davidson College and then matriculated to Wake Forest University where she completed her medical degree before matching at UVA. She is interested in full scope family medicine with an emphasis on preventive care.

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