A randomized clinical trial of glenohumeral joint steroid injection versus suprascapular nerve block in patients with frozen shoulder: a protocol for the Therapeutic Injections For Frozen Shoulder (TIFFS) study

Frozen shoulder is a common, painful condition that results in impairment of function. Corticosteroid injections are commonly used for frozen shoulder and can be given as glenohumeral joint (GHJ) injection or suprascapular nerve block (SSNB). Both injection types have been shown to significantly improve shoulder pain and range of motion. It is not currently known which is superior in terms of relieving patients' symptoms. This is the protocol for a randomized clinical trial to investigate the clinical effectiveness of corticosteroid injection given as either a GHJ injection or SSNB. The Therapeutic Injections For Frozen Shoulder (TIFFS) study is a single centre, parallel, two-arm, randomized clinical trial. Participants will be allocated on a 1:1 basis to either a GHJ corticosteroid injection or SSNB. Participants in both trial arms will then receive physiotherapy as normal for frozen shoulder. The primary analysis will compare the Oxford Shoulder Score (OSS) at three months after injection. Secondary outcomes include OSS at six and 12 months, range of shoulder movement at three months, and Numeric Pain Rating Scale, abbreviated Disabilities of Arm, Shoulder and Hand score, and EuroQol five-level five-dimension health index at three months, six months, and one year after injection. A minimum of 40 patients will be recruited to obtain 80% power to detect a minimally important difference of ten points on the OSS between the groups at three months after injection. The study is registered under ClinicalTrials.gov with the identifier NCT04965376. The results of this trial will demonstrate if there is a difference in shoulder pain and function after GHJ injection or SSNB in patients with frozen shoulder. This will help provide effective treatment to patients with frozen shoulder.

The Impact of Suprascapular Nerve Interventions in Patients with Frozen Shoulder: A Systematic Review and Meta-Analysis

BACKGROUND

Frozen shoulder is a common condition resulting in severe pain and restricted range of motion. An assessment of the effectiveness of interventions may provide an improved understanding of the development and management of frozen shoulder.

METHODS

A literature search was conducted using Embase, the Cumulative Index of Nursing and Allied Health (CINAHL), the Cochrane Central Register of Controlled Trials (CENTRAL), and National Center for Biotechnology Information PubMed using relevant terms. Studies were included if they assessed the outcomes of interventions on the suprascapular nerve that aim to improve the symptoms of frozen shoulder.

RESULTS

A database search returned 196 articles. After review, 9 articles met the inclusion criteria and were included in the analysis. Suprascapular nerve interventions (nerve block, pulsed radiofrequency lesioning) are associated with improvement in pain, motion, and function. Meta-analysis showed that pain (Hedges g, -3.084 [95% confidence interval (CI), -4.273 to -1.894]; p < 0.001) and range of motion (Hedges g, 2.204 [95% CI, 0.992 to 3.415]; p < 0.001) improved significantly following suprascapular nerve block (SSNB).

CONCLUSIONS

SSNB is associated with significant improvements in shoulder pain and range of motion in patients with frozen shoulder. Further randomized controlled trials comparing SSNB with intra-articular injection and other nonoperative treatments are required to fully define its role in the management of frozen shoulder.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Frozen Shoulder: A Systematic Review of Cellular, Molecular, and Metabolic Findings

BACKGROUND

Frozen shoulder is a common, poorly understood condition affecting the shoulder joint, with poor long-term outcomes in some in relation to pain and mobility. Understanding the pathophysiology of frozen shoulder at a cellular level and a molecular level may help in the development of novel treatments. The aim of this study was to perform a systematic review of studies examining the cellular, molecular, and metabolic findings in frozen shoulder.

METHODS

A literature search was conducted using Embase, CINAHL (Cumulative Index of Nursing and Allied Health Literature), and PubMed using relevant terms. Studies were included if they assessed cellular, molecular, or metabolic alterations in tissue or blood samples of patients with frozen shoulder.

RESULTS

Of 4,794 studies identified, 25 were included for analysis. Histological findings included nonspecific chronic inflammation and the proliferation of fibroblasts, adipocytes, and blood vessels. Molecular studies showed increased pro-inflammatory mediators, reduced matrix metalloproteinases (MMPs), and increased activity of factors promoting fibroblast activation and nerve growth. Metabolic alterations included an increase in blood lipids.

CONCLUSIONS

Frozen shoulder is thought to occur after a primary insult to the shoulder triggers a complex cascade and upregulation of growth factors and cytokines with an increased turnover of the extracellular matrix, activation of myofibroblasts with deposition of collagen, and reduced matrix degradation. The presence of a background pro-inflammatory state (e.g., patients with diabetes or hyperlipidemia) may exacerbate these abnormalities. Further work assessing patients in early stages of the disease and comparing the inflammatory or fibrogenic characteristics of the shoulder capsule with those of the other joints may help to determine the initiating factors and to explain the predisposition of the shoulder to stiffness.

CLINICAL RELEVANCE

Our findings may form the basis for identifying new targets for the clinical management of frozen shoulder.