This prospective, two-center, randomized controlled clinical trial aims to compare the effectiveness of ultrasound-guided pulsed radiofrequency and 5% dextrose injection in patients with chronic plantar fasciitis. Eligible participants will be randomized into two parallel groups. One group will receive ultrasound-guided pulsed radiofrequency treatment, and the other group will receive ultrasound-guided 5% dextrose injection using the peppering technique. All participants will receive a home-based plantar fascia stretching exercise program. Outcomes will be assessed at baseline, 3 weeks, 6 weeks, and 12 weeks after treatment. The primary outcome will be pain intensity measured by the Numeric Rating Scale. Secondary outcomes will include foot function, activity-related pain, ankle-hindfoot function, and health-related quality of life.

Plantar fasciitis is one of the most common causes of chronic heel pain in adults. It may impair walking pattern, daily activities, social life, and work-related functioning. Although conservative treatments are commonly used as first-line therapy, symptoms may become chronic in a considerable proportion of patients.

Dextrose injection is a regenerative injection treatment used in chronic musculoskeletal pain conditions. It is thought to stimulate local tissue healing responses through controlled inflammatory and proliferative mechanisms. Pulsed radiofrequency is a minimally invasive, non-neurodestructive radiofrequency technique used for pain control. Both pulsed radiofrequency and dextrose injection are used in clinical practice for resistant chronic plantar fasciitis; however, comparative data between these two approaches are limited.

This study will be conducted as a prospective, two-center, two-arm, parallel-group randomized controlled trial in the Physical Medicine and Rehabilitation clinics of Ankara Bilkent City Hospital and Adana City Hospital. Participants with chronic plantar fasciitis will be randomized in a 1:1 ratio using the sealed-envelope method. The investigator responsible for randomization will know the allocation, while the outcomes assessor will be blinded to treatment allocation. Blinding of the interventionists will not be possible due to the nature of the procedures.

Participants in the pulsed radiofrequency group will receive ultrasound-guided pulsed radiofrequency treatment at baseline. Participants in the 5% dextrose group will receive ultrasound-guided 5% dextrose injection around the medial calcaneal insertion of the plantar fascia using the peppering technique, with 0.1-0.2 mL administered at each entry point. Dextrose injections will be performed in three sessions at 3-week intervals.

All participants will receive a home-based plantar fascia stretching exercise program. Exercises will be demonstrated by a physiotherapist, and participants will be instructed to perform the exercises twice daily for 12 weeks. Participants will be monitored for possible adverse events or complications for at least 30 minutes after the procedure. Clinical outcomes will be assessed at baseline, 3 weeks, 6 weeks, and 12 weeks.

Inclusion Criteria:

• Diagnosis of chronic plantar fasciitis based on medical history and physical examination
• Heel pain resistant to conservative treatment for at least 12 weeks
• Age between 18 and 70 years
• Willingness to participate in the study and provide written informed consent

Exclusion Criteria:

• Congenital or acquired disease that may impair or prevent foot function, such as rheumatoid arthritis, hemiplegia, congenital foot deformity, traumatic foot or leg amputation, or fracture sequelae
• Local infection or skin disease at the treatment site
• Bleeding disorder or use of anticoagulant medication within the last week
• Disease causing mental dysfunction, such as uncontrolled Parkinson disease or Alzheimer disease
• Previous surgery for plantar fasciitis
• Refusal to participate in the study or inability to provide informed consent
• Failure to attend follow-up visits after treatment
• Request to withdraw from the study
• Pregnancy or suspected pregnancy
• Presence of a cardiac pacemaker
• History of epilepsy
• Active or previous malignancy
• Rheumatologic disease

The outcomes assessor will be blinded to treatment allocation. Blinding of the interventionists will not be possible due to the nature of the procedures.