Lateral epicondylitis is a common and often debilitating condition characterized by pain over the lateral aspect of the elbow. Although many patients respond to standard conservative treatments, a subset develops a chronic and treatment-resistant form of the condition.

The primary objective of this randomized comparative clinical trial is to evaluate and compare the therapeutic effectiveness of two intervention modalities: Extracorporeal Shock Wave Therapy (ESWT) and ultrasound-guided ozone injection in patients with chronic lateral epicondylitis.

Participants who meet the inclusion criteria will be randomly assigned to one of two treatment arms. The first group will receive Extracorporeal Shock Wave Therapy (ESWT), while the second group will receive an ultrasound-guided injection of an ozone-oxygen mixture. Both interventions will be administered once weekly for three consecutive weeks according to their respective standard treatment protocols.

To determine which treatment yields superior clinical and structural outcomes, participants will be evaluated at three time points: baseline (prior to treatment), immediately after completion of the 3-week treatment protocol, and at a 4-week follow-up. Outcome measures will include pain intensity assessed using the Visual Analog Scale (VAS), functional status evaluated with the Patient-Rated Tennis Elbow Evaluation (PRTEE), hand grip strength measured with a dynamometer, and structural tendon changes (tendon thickness and presence of enthesophytes) assessed by high-resolution ultrasonography.

Lateral epicondylitis is a painful and often debilitating tendinopathy affecting the common extensor tendon origin. Although most patients respond to standard conservative management, a substantial proportion progress to a chronic, refractory condition. For these resistant cases, identifying effective and minimally invasive treatment options remains a significant clinical challenge.

Extracorporeal Shock Wave Therapy (ESWT) is a non-invasive modality widely used in the management of chronic tendinopathies. Its proposed therapeutic mechanisms include the induction of controlled microtrauma, stimulation of neoangiogenesis, increased local blood flow, and modulation of pain-related signaling pathways, ultimately promoting tissue regeneration.

Medical ozone therapy has emerged as a potential regenerative injection approach. The local administration of an oxygen-ozone gas mixture into the affected tissue is thought to exert anti-inflammatory effects, enhance tissue oxygenation, and stimulate fibroblast activity, thereby supporting cellular repair processes within degenerated tendon tissue.

Although both modalities demonstrate potential therapeutic benefits, direct comparative evidence regarding their effectiveness in chronic, treatment-resistant lateral epicondylitis remains limited. This study aims to compare the clinical and structural outcomes associated with these two treatment approaches. By evaluating both symptom improvement and objective ultrasonographic tendon changes, this trial seeks to provide evidence to inform optimal treatment strategies for chronic cases.

Inclusion Criteria:

• Age: Male or female patients between 18 and 65 years of age.
• Clinical Diagnosis: Patients diagnosed with lateral epicondylitis, defined by pain in the lateral epicondyle region for more than 3 months, increased pain on palpation of the lateral epicondyle, and positive provocation tests (Cozen's, Maudsley's, or Mills' tests).
• Symptom Duration: Presence of symptoms for more than 3 months (resistant cases).
• Treatment Failure: Lack of response to first-line conservative treatments (e.g., analgesics, exercise, rest, splinting).
• Radiographic Confirmation: No other pathology detected on direct radiographs of the elbow.
• Injection History: No corticosteroid injection to the affected elbow within the last 6 months.
• Consent: Voluntary participation in the study

Exclusion Criteria:

• Elbow Pathology: Presence of elbow problems other than lateral epicondylitis (e.g., loose bodies, rheumatoid nodules).
• Surgical History: History of previous surgery on the affected elbow joint.
• Structural Damage: Presence of tendon rupture.
• Consent: Unwillingness to continue treatment or participate.
• Spinal Pathology: Cervical root pathology (cervical radiculopathy).
• Neuropathy: Diagnosed upper extremity entrapment neuropathy.
• Neurological Status: Presence of neurological impairment or deficits.
• Recent Injections: History of injection therapy to the elbow within the last 6 months.
• Recent Therapy: History of physical therapy for the elbow region within the last 6 months.
• Pregnancy: Pregnant women.
• Hematological: Presence of coagulation or bleeding disorders.
• Vascular: Presence of peripheral vasculopathy.
• Pain Syndromes: Presence of Complex Regional Pain Syndrome (CRPS).
• Oncology: History of malignancy.
• Systemic Diseases: Presence of systemic inflammatory or autoimmune disorders (e.g., Rheumatoid Arthritis, SLE).
• Trauma: History of direct trauma to the elbow.
• Medication: Current use of medications that may affect pain levels or muscle strength (e.g., muscle relaxants, analgesics, gabapentinoids).
• Local Infection: Presence of open wounds, infection, or signs of active inflammation in the elbow region.
• Cooperation: Difficulty in cooperation or cognitive inability to follow instructions.
• Enzyme Deficiency: Congenital Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency.