The aim of this randomized controlled trial is to compare the effects of percutaneous electrolysis combined with exercise versus exercise alone on pain and function in patients with chronic lateral epicondylitis. Participants will be randomly allocated into two parallel groups. The control group will receive a 2-week exercise program including stretching and eccentric strengthening exercises for the wrist extensor and forearm muscles. The experimental group will receive the same exercise program plus three sessions of ultrasound-guided percutaneous electrolysis applied to the extensor carpi radialis brevis tendon insertion at the lateral epicondyle (on days 1, 8, and 14). Clinical outcomes will be assessed using a 10-cm Visual Analog Scale (VAS) for pain intensity, pressure pain threshold over the common extensor tendon measured with a handheld algometer, the Patient-Rated Tennis Elbow Evaluation (PRTEE) questionnaire for pain and functional disability, and the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire for upper limb function. Assessments will be performed at baseline, and then at 1 week, 1 month, and 3 months after the end of the 2-week treatment period. The study aims to determine whether adding percutaneous electrolysis to an exercise program provides greater improvement in pain and functional status than exercise alone in patients with chronic lateral epicondylitis.