Frozen shoulder (adhesive capsulitis) is characterized by pain and a progressive restriction of both active and passive shoulder range of motion, significantly impairing daily activities and quality of life. This study aims to evaluate the effectiveness of USG-guided shoulder injections, when added to a home-based exercise program, in the conservative management of patients with chronic, painful frozen shoulder.

In this prospective randomized study, patients diagnosed with painful frozen shoulder will be included. In addition to a standardized home-based exercise program, patients will receive either USG-guided suprascapular nerve block alone or a combination of suprascapular nerve block and subacromial injection. The effects of these approaches on clinical outcomes will be assessed over a 20-week follow-up period.

Primary outcome measures include pain intensity assessed by the Visual Analog Scale (VAS), functional status evaluated by the Shoulder Pain and Disability Index (SPADI), and shoulder range of motion. Secondary outcomes include depression level (Beck Depression Inventory), sleep quality, pain phenotype (nociplastic, neuropathic, or nociceptive), hand grip strength, ultrasonographic findings ( (coracohumeral ligament thickness, subacromial bursa thickness) , and patient satisfaction (subjective impression of improvement).

The results of this study are expected to provide evidence on the comparative effectiveness and additional benefits of different shoulder injection approaches when combined with home-based exercise therapy in patients with chronic frozen shoulder.

This study will include patients presenting to the Physical Medicine and Rehabilitation outpatient clinics of Konya Beyhekim Training and Research Hospital with chronic shoulder pain and restricted range of motion, who are clinically diagnosed with frozen shoulder following a comprehensive evaluation. A total of 68 consecutive patients aged 18-75 years, with shoulder pain lasting at least three months and diagnosed with frozen shoulder after appropriate differential diagnosis, who consent to participate will be enrolled. All participants will provide written informed consent for study participation. Sociodemographic characteristics and clinical examination findings will be recorded for all participants.

As part of the clinical examination, patients will be evaluated for diagnosis and differential diagnosis based on the results of impingement tests, the drop arm sign, shoulder ultrasonography (e.g., presence of significant effusion, rotator cuff tear, etc.), and plain radiography. Following assessment according to predefined inclusion and exclusion criteria, patients will be randomized (block randomization) to receive either USG-guided suprascapular nerve block alone or a combination of suprascapular nerve block and subacromial injection.

Patients' sociodemographic data, as well as detailed clinical and examination findings and baseline outcomes, will be recorded. Patients will be informed about their condition, and modifications to activities of daily living will be recommended. Patients' pain phenotypes (nociceptive, neuropathic, nociplastic) will be categorized based on clinical history and validated questionnaires, and it will be determined which pain types derive greater benefit from these injections.

As part of an individualized home-based exercise program, patients in both groups will perform range-of-motion exercises, Codman exercises, isometric strengthening, and stretching within their self-limited pain threshold. The home exercise program will be demonstrated in person by a physician or physiotherapist, and written printed materials will be provided to the patients. Exercise adherence will be assessed at the 3rd, 6th, and 20th week follow-up visits, and when necessary, patients will be contacted by telephone to support and monitor adherence to the exercise program. Patients with less than 70% adherence will be excluded from the analysis.

In the first group (USG-guided suprascapular nerve block group), a suprascapular nerve block will be administered under ultrasound guidance in accordance with the literature (triamcinolone 20 mg/1 mL + 1% lidocaine 4 mL). In the second group (combination of suprascapular nerve block and subacromial injection group), patients will receive, in a similar manner under ultrasound guidance, a suprascapular nerve block (triamcinolone 10 mg/0.5 mL + 1% lidocaine 4 mL + 0.5 mL saline), followed by an ultrasound-guided subacromial/deltoid bursa injection (triamcinolone 10 mg/0.5 mL + 1% lidocaine 2.5 mL). Patients will be blinded to the type of these injections administered to them. At the 3-week follow-up after the first injection, for patients in both groups who do not show sufficient reduction in pain (defined as a decrease of less than 3 points on the VAS or less than 50% reduction) and who are willing to proceed, repeat injections will be administered in the same manner based on a joint decision between the patient and the physician.

No additional treatments such as extra medications, additional injections, or manipulations will be administered to the patients. For pain relief, patients will be allowed to take paracetamol 500 mg tablets as needed (2-3 times daily). Any analgesic use due to pain will be recorded. Patients will be specifically instructed not to take any analgesics within 24 hours prior to follow-up assessments Patients will be followed to assess their pain and functional status, and primary and secondary outcome measures will be recorded at three time points: before treatment (baseline), at 6 weeks, and at 20 weeks.

At these follow-up visits, a blinded assessor will evaluate the groups. Pain intensity will be assessed using the Visual Analog Scale (VAS; 0-10) for both night pain and pain with movement. Shoulder range of motion (flexion, abduction, internal and external rotation) will be measured using a goniometer. Functional status will be evaluated using the Shoulder Pain and Disability Index (SPADI). Sleep quality will be assessed using the single-item Simple Sleep Quality Scale, and mood will be evaluated using the Beck Depression Inventory.

Ultrasonographic evaluation of the shoulder will be performed to measure coracohumeral ligament and subacromial bursa thickness, and the findings will be recorded. All potential adverse events will be closely monitored and documented throughout the follow-up period. Additionally, patient satisfaction (subjective impression of improvement) level will be assessed using a Likert-type questionnaire (1 = very dissatisfied, 5 = very satisfied).

Inclusion Criteria:

Age between 18 and 75 years and willingness to participate in the study

Presence of shoulder pain lasting at least 3 months and a diagnosis of primary frozen shoulder

Pain intensity ≥ 4/10 on the Visual Analog Scale (VAS), resistant to medical treatment/analgesics

Restriction of ≥30 degrees in at least two planes of shoulder motion (flexion, abduction, or external rotation)

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Exclusion Criteria:

• History of shoulder trauma

Presence of neurological conditions such as stroke, brachial plexus injury, Parkinson's disease, or cervical spine pathology with or without radiculopathy

History of shoulder surgery, shoulder malignancy or tumor, or prior shoulder manipulation

Presence of shoulder arthritis, rotator cuff tear, other shoulder injuries, or thoracic outlet syndrome

Systemic diseases affecting the shoulder, severe degeneration or trauma (e.g., osteoarthritis, rheumatoid arthritis, labral or articular cartilage injuries), or inflammatory rheumatic diseases

Steroid injection to the affected extremity within the last 3 months, use of oral steroids or NSAIDs, or ongoing surgical/interventional treatment

Pregnancy or lactation

Uncontrolled diabetes, heart failure, or uncontrolled systemic diseases (e.g., liver failure, chronic kidney disease, significant endocrine disorders)

Communication problems or severe psychiatric disorders

Patient information is confidential.

double-blind