This study aims to compare the effectiveness of ultrasound-guided betamethasone and dextrose injections in patients with trigger finger.

Trigger finger is a common hand condition characterized by pain, clicking, and locking of the finger due to tendon entrapment at the A1 pulley. Corticosteroid injections are widely used as a first-line treatment; however, they may be associated with potential side effects.

Dextrose injection is an alternative treatment that may promote tissue healing through regenerative mechanisms. However, there is limited high-quality evidence regarding its effectiveness in trigger finger.

In this randomized controlled trial, patients will be assigned to receive either betamethasone or dextrose injection under ultrasound guidance. The primary outcome will be pain intensity measured by the Numeric Rating Scale (NRS). Secondary outcomes will include triggering severity, hand function, grip and pinch strength, and fine motor skills evaluated over a 12-week follow-up period.

The results of this study may help determine whether dextrose injection is a safe and effective alternative to corticosteroid treatment in trigger finger.

Trigger finger, also known as stenosing tenosynovitis, is a common hand disorder characterized by pain, catching, and locking of the affected digit due to impaired gliding of the flexor tendon at the A1 pulley. It can significantly impair hand function and quality of life.

Corticosteroid injections are widely accepted as an effective first-line treatment for trigger finger. However, potential adverse effects such as skin atrophy, tendon rupture, and systemic effects, particularly in patients with metabolic disorders, have led to increasing interest in alternative treatment options.

Dextrose injection has emerged as a potential alternative treatment modality in musculoskeletal disorders. However, there is limited high-quality evidence evaluating its effectiveness in trigger finger.

The aim of this prospective, randomized controlled trial is to compare the clinical effectiveness of ultrasound-guided betamethasone injection and dextrose injection in patients with trigger finger.

Eligible participants aged 18 to 75 years with clinically diagnosed trigger finger of at least 4 weeks' duration will be enrolled. Patients will be randomly assigned to one of two groups. One group will receive an ultrasound-guided injection of 1 ml lidocaine and 1 ml betamethasone, while the other group will receive an ultrasound-guided injection of 1 ml lidocaine and 1 ml 30% dextrose solution (resulting in a final concentration of 15% dextrose). All injections will be performed under sterile conditions at the A1 pulley level.

The study is designed as a randomized, participant-, injector-, and assessor-blinded trial. The injector will be blinded to the injectate using opaque-covered syringes. Randomization will be performed by an independent researcher who will not be involved in outcome assessment.

The primary outcome of the study is the change in pain intensity, assessed using the Numeric Rating Scale (NRS).

Secondary outcomes include triggering severity assessed using the Modified Quinnell classification, functional status assessed using the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire, grip and pinch strength, and fine motor skills evaluated with the Purdue Pegboard test.

Outcome assessments will be conducted at baseline, 1 hour, 2 weeks, 4 weeks, and 12 weeks after injection, according to the predefined schedule of each outcome measure.

This study is expected to provide high-quality evidence regarding the effectiveness of dextrose injection as a potential alternative to corticosteroid treatment in trigger finger.

Inclusion Criteria:

• Age between 18 and 75 years
• Clinical diagnosis of trigger finger
• Presence of symptoms for at least 4 weeks

Exclusion Criteria:

• Previous surgery on the affected finger
• Injection treatment to the affected finger within the previous 3 months
• Active local or systemic infection
• Active malignancy
• Active inflammatory rheumatic disease (e.g., rheumatoid arthritis, ankylosing spondylitis, polymyalgia rheumatica, vasculitis)
• Uncontrolled diabetes mellitus and/or uncontrolled hypertension
• Autoimmune connective tissue diseases (e.g., systemic lupus erythematosus, antiphospholipid syndrome, systemic sclerosis, Sjögren syndrome, polymyositis, dermatomyositis, adult-onset Still's disease)
• Coagulopathy that increases the risk of injection procedures
• Pregnancy
• Known allergy or hypersensitivity to lidocaine, betamethasone, or dextrose
• Mental impairment or severe psychiatric disorder that may interfere with study participation or informed consent

The investigators have not yet determined whether de-identified individual participant data (IPD) will be shared. If data sharing is approved after completion of the study and publication of the primary results, the de-identified dataset underlying the reported outcomes may be made available. Any decision regarding data sharing will be based on institutional policies, ethical approval, participant confidentiality, and applicable regulations.

Participants, the injector investigator, and the outcome assessor will be blinded to treatment allocation. Injections will be prepared by an independent researcher using opaque-covered syringes so that the injector investigator will not be aware of the injected solution. Randomization will be performed by an independent researcher who will not participate in outcome assessment.