This retrospective, controlled clinical study aims to evaluate the effectiveness of a targeted biological support injection containing a hyaluronic acid and amino acid combination in patients with chronic lateral epicondylitis (tennis elbow). Medical records will be reviewed to compare outcomes between patients treated in routine clinical practice with a 3-dose injection regimen (weeks 0, 2, and 4) plus a home exercise program and those treated with a home exercise program alone. Key outcome measures include pain intensity (VAS), functional status (PRTEE), grip strength, and pressure pain threshold.

Inclusion Criteria:

• Patients aged between 18 and 70 years.
• Patients diagnosed with Lateral Epicondylitis (LE).
• Presence of symptoms persisting for 6 weeks or longer.
• Patients who were treated with either a 3-dose protocol of Hyaluronic Acid + Amino Acid injection combined with a home exercise program, or a home exercise program alone.

Exclusion Criteria:

• History of rheumatic disease.
• History of malignancy.
• Presence of radiculopathy or neuropathy.
• Presence of peripheral circulatory disorders.
• Congenital or acquired upper extremity deformities.
• History of coagulopathy or current use of warfarin therapy.
• Presence of prosthesis, metal implant, or internal fixator in the elbow region.

Patients diagnosed with chronic Lateral Epicondylitis who applied to the Physical Medicine and Rehabilitation outpatient clinic of Sivas State Hospital. The study involves the retrospective analysis of patients treated between June 01, 2025, and November 01, 2025.