Background:

Lateral epicondylitis is a common musculoskeletal condition characterized by pain and functional impairment of the elbow, often associated with degenerative changes in the common extensor tendon. Extracorporeal shock wave therapy (ESWT) and low-level laser therapy (LLLT) are widely used noninvasive treatment modalities; however, comparative evidence regarding their clinical and structural effects remains limited.

Objective:

This study aims to compare the effects of ESWT and LLLT on pain intensity, elbow function, quality of life, grip strength, and ultrasonographic characteristics of the extensor tendon (thickness and echogenicity) in patients with lateral epicondylitis.

Methods:

This prospective, randomized, single-blind, comparative clinical trial will be conducted at the Physical Medicine and Rehabilitation outpatient clinic. Patients aged 18-65 years with clinically diagnosed lateral epicondylitis and symptom duration of at least six weeks will be included. All participants will receive a tennis elbow brace and a standardized exercise program. Participants will be randomly assigned to receive either ESWT or LLLT. ESWT will be applied to the lateral epicondyle region using a standardized protocol once weekly for 3 weeks. LLLT will be administered to the same region using standard clinical protocol three times per week for 3 weeks.

Assessments will be performed before and after treatment. Pain will be evaluated using the Visual Analog Scale (VAS), elbow function using the Patient-Rated Tennis Elbow Evaluation (PRTEE), quality of life using the Short Form-36 (SF-36), and grip strength using a hand dynamometer. Ultrasonographic evaluation of the common extensor tendon will be performed by a blinded specialist using a high-frequency linear probe to assess tendon thickness.

Lateral epicondylitis is a common overuse disorder characterized by degenerative changes in the common extensor tendon, particularly the extensor carpi radialis brevis. Current evidence suggests that the condition represents a tendinopathic process rather than an inflammatory disorder, emphasizing the importance of treatments targeting both symptom relief and tendon healing.

Extracorporeal shock wave therapy (ESWT) and low-level laser therapy (LLLT) are widely used noninvasive treatment modalities in clinical practice. ESWT is thought to promote tendon healing through mechanotransduction and neovascularization, whereas LLLT may enhance cellular metabolism, fibroblast proliferation, and collagen synthesis. Although both treatments have demonstrated clinical benefits, comparative data evaluating their effects on both clinical outcomes and tendon structure are limited.

This study is designed as a prospective, randomized, single-blind, comparative clinical trial conducted at the Physical Medicine and Rehabilitation outpatient clinic of Hitit University. Eligible participants aged 18-65 years with clinically diagnosed lateral epicondylitis and symptom duration of at least six weeks will be randomly assigned to receive either ESWT or LLLT using a computer-generated randomization sequence. Outcome assessors will be blinded to group allocation.

ESWT will be applied to the lateral epicondyle region over the common extensor tendon using a standardized protocol (1.6 bar, 2000 pulses, 10 Herz, once weekly for 3 weeks). LLLT will be administered to the same anatomical region three times per week for 3 weeks (four points, 40 seconds per point, 4 joules per square centimeter (J/cm²). In addition, all participants will receive a tennis elbow brace and a standardized exercise program. No additional physical therapy modalities or changes in ongoing medical treatments will be allowed during the study period.

Clinical assessments will be performed at baseline and immediately after treatment. Pain intensity will be measured using the Visual Analog Scale (VAS). Elbow function will be evaluated using the Patient-Rated Tennis Elbow Evaluation (PRTEE). Quality of life will be assessed with the Short Form-36 (SF-36), and grip strength will be measured using a hand dynamometer.

Ultrasonographic evaluation will be performed by an experienced physiatrist blinded to treatment allocation, using a high-frequency linear probe. The common extensor tendon will be assessed in both longitudinal and transverse planes. Tendon thickness will be measured in millimeters.

The primary aim is to compare the effects of ESWT and LLLT on pain and tendon thickness, while secondary outcomes include functional scores, quality of life, grip strength, and tendon echogenicity. It is hypothesized that both treatments will improve clinical outcomes, with ESWT potentially providing greater structural improvement in tendon characteristics.

Inclusion Criteria:

• Clinical diagnosis of lateral epicondylitis based on physical examination findings
• Symptom duration of at least 6 weeks
• Presence of lateral elbow pain aggravated by wrist extension and/or gripping activities
• Ability to understand and comply with study procedures
• Provision of written informed consent

Exclusion Criteria:

• Previous surgery involving the affected elbow
• History of corticosteroid or other injection therapy to the affected elbow within the last 6 months
• Presence of inflammatory rheumatic diseases (e.g., rheumatoid arthritis)
• Neurological disorders affecting the upper extremity
• Systemic inflammatory or metabolic diseases that may affect tendon structure or healing
• Cervical radiculopathy or other causes of referred upper extremity pain
• Pregnancy or breastfeeding
• Use of anticoagulant therapy or bleeding disorders
• Severe comorbid conditions that may interfere with participation

Individual participant data will not be shared due to institutional regulations and the absence of participant consent for public data sharing.

Single (Outcome assessor)