Low-Dose Radiotherapy for Painful Knee Osteoarthritis

NCT07886697 | Not Yet Recruiting

• 2 other identifiers: LDRT-KOA-MC-0124/63
• Study Type: interventional
• Target: 283
• Locations: 1 country
• Sites: 4

Brief Summary

Knee osteoarthritis is a common cause of chronic pain and difficulty with everyday activities, particularly in older adults. Some patients continue to experience clinically relevant knee pain despite medication, therapeutic exercise, physiotherapy, or other conservative treatments. This prospective, multicenter study will evaluate changes in pain, physical function, health-related quality of life, and safety after low-dose radiotherapy (LDRT) in adults aged 60 years or older with painful primary knee osteoarthritis. All participants will receive the same treatment, and there will be no control or sham-treatment group. Participants will receive one course of low-dose radiotherapy to the study knee, consisting of six fractions of 0.5 Gy, for a total dose of 3.0 Gy, administered twice weekly on nonconsecutive days over approximately 3 weeks. Clinical assessments will be performed before treatment and approximately 45 and 90 days after the last radiotherapy fraction. The main outcome is the change from baseline to Day 90 in average knee pain during the previous 7 days, measured on a 0-to-10 Numerical Rating Scale. The study hypothesis is that average knee pain will be lower at Day 90 than before treatment. Other outcomes include physical function, health-related quality of life, the participant's overall assessment of the affected knee, pain response, analgesic use, treatment completion, additional knee treatments, and adverse events.

Conditions

Knee Osteoarthritis

Keywords

Low-Dose Radiotherapy; Painful Knee Osteoarthritis; Knee Pain; LDRT; Radiotherapy for Benign Disease; Degenerative Joint Disease

Outcome Measures

Primary Outcomes (1)

• Change From Baseline in Average Index-Knee Pain Intensity at Day 90

  Average pain intensity in the index knee during the previous 7 days will be assessed using an 11-point Numerical Rating Scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain). Change will be calculated as baseline NRS minus Day 90 NRS. Positive values indicate improvement, zero indicates no change, and negative values indicate worsening.

  Baseline and Day 90 (90 ± 14 days after the last radiotherapy fraction)

Secondary Outcomes (15)

• Change From Baseline in Average Index-Knee Pain Intensity at Day 45

  Baseline and Day 45 (45 ± 7 days after the last radiotherapy fraction)

• Change From Baseline in WOMAC Pain Subscale Score

  Baseline, Day 45 (45 ± 7 days after the last radiotherapy fraction), and Day 90 (90 ± 14 days after the last radiotherapy fraction)

• Change From Baseline in WOMAC Stiffness Subscale Score

  Baseline, Day 45 (45 ± 7 days after the last radiotherapy fraction), and Day 90 (90 ± 14 days after the last radiotherapy fraction)

• Change From Baseline in WOMAC Physical Function Subscale Score

  Baseline, Day 45 (45 ± 7 days after the last radiotherapy fraction), and Day 90 (90 ± 14 days after the last radiotherapy fraction)

• Change From Baseline in KOOS-PS Score

  Baseline, Day 45 (45 ± 7 days after the last radiotherapy fraction), and Day 90 (90 ± 14 days after the last radiotherapy fraction)

Study Arms (1)

Low-Dose Radiotherapy

EXPERIMENTAL

Participants will receive a single course of low-dose radiotherapy to the index knee consisting of six fractions of 0.5 Gy, for a total dose of 3.0 Gy, administered twice weekly on nonconsecutive days over approximately 3 weeks.

Radiation: Low-Dose Radiotherapy (LDRT)

Interventions

Low-Dose Radiotherapy (LDRT) RADIATION

Low-dose radiotherapy will be delivered to the index knee as six fractions of 0.5 Gy each, for a total prescribed dose of 3.0 Gy. Fractions will be administered twice weekly on nonconsecutive days over approximately 3 weeks. Treatment will be planned using computed tomography simulation. The clinical target volume will include the relevant femoral and tibial articular and subchondral surfaces, joint capsule, synovium, and periarticular tissues. A nominal 5-mm planning target volume margin will be applied. Treatment will be delivered using opposed anteroposterior and posteroanterior fields with 6-MV photons.

Low-Dose Radiotherapy

Eligibility Criteria

• Age: 60 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 60 years or older.
• Clinical and radiographic diagnosis of primary knee osteoarthritis.
• Kellgren-Lawrence grade II or III osteoarthritis in the index knee.
• Pain in the index knee for at least 6 months.
• Baseline average index-knee pain intensity greater than 4 on a 0-to-10
• Numerical Rating Scale (NRS), referring to the previous 7 days.
• Persistent clinically relevant knee pain despite documented prior conservative management. Conservative management must include pharmacological treatment appropriate to the participant's clinical profile and therapeutic exercise and/or physiotherapy. If any of these measures were not undertaken because of contraindication, intolerance, or clinical inability, the reason must be documented.
• Ability to understand the study procedures and reliably complete the required clinical assessments and questionnaires.
• Written informed consent to participate in the study.

You may not qualify if:

• Kellgren-Lawrence grade 0, I, or IV in the index knee.
• Knee prosthesis in the index knee.
• Previous radiotherapy involving the treatment region.
• Body mass index greater than 39 kg/m².
• Active connective tissue disease with clinically relevant skin or soft-tissue involvement in the treatment region, including active systemic lupus erythematosus or rheumatoid arthritis when considered clinically relevant for radiotherapy.
• Fibromyalgia or a psychiatric disorder that, in the investigator's judgment, would substantially compromise reliable assessment of pain or patient-reported outcomes.
• Inability to provide informed consent or to reliably complete the required study assessments.

Sponsors & Collaborators

• Universidad Rey Juan Carlos: lead
• Hospital Universitario de Fuenlabrada: collaborator
• Hospital General Universitario de Valencia: collaborator
• Hospital Universitario Clínico San Cecilio: collaborator
• Ascires Grupo Biomédico: collaborator

Study Sites (4)

Hospital Universitario Clínico San Cecilio

Granada, Granada, 18016, Spain

Location

Hospital Universitario de Fuenlabrada

Fuenlabrada, Madrid, 28942, Spain

Location

Hospital Ascires Valencia

Valencia, Valencia, 46014, Spain

Location

Hospital General Universitario de Valencia

Valencia, Valencia, 46014, Spain

Location

Related Publications (5)

• Muller JA, Alsalloum J, Vordermark D, Delank S. KORT - Knee osteoarthrosis radiotherapy trial: Protocol for a multidisciplinary pathway and a planned sham-controlled phase III trial of low-dose radiotherapy in knee osteoarthritis. Osteoarthr Cartil Open. 2026 Feb 27;8(2):100764. doi: 10.1016/j.ocarto.2026.100764. eCollection 2026 Jun.

  PMID: 41859527 BACKGROUND

• Fazilat-Panah D, Javadinia SA, Shabestani Monfared A, Attarian F, Babaei M, Yousefghahari B, Najafzadeh Sadati S, Ahmadi N, Fallah Tafti H. Effects of low dose rate radiotherapy on pain relief, performance score, and quality of life in patients with knee osteoarthritis; a double-blind sham-controlled randomized clinical trial. Int J Radiat Biol. 2025;101(5):541-548. doi: 10.1080/09553002.2025.2473975. Epub 2025 Mar 5.

  PMID: 40043233 BACKGROUND

• Kim BH, Shin K, Kim MJ, Kim HJ, Ro DH, Wang JH, Lee DH, Kim DH, Sun J, Lee JH, Kim JY, Hong EH, Cho SJ, Han HS, Park W. Low-dose RaDiation therapy for patients with KNee osteoArthritis (LoRD-KNeA): a protocol for a sham-controlled randomised trial. BMJ Open. 2023 Feb 10;13(2):e069691. doi: 10.1136/bmjopen-2022-069691.

  PMID: 36764712 BACKGROUND

• Mahler EAM, Minten MJ, Leseman-Hoogenboom MM, Poortmans PMP, Leer JWH, Boks SS, van den Hoogen FHJ, den Broeder AA, van den Ende CHM. Effectiveness of low-dose radiation therapy on symptoms in patients with knee osteoarthritis: a randomised, double-blinded, sham-controlled trial. Ann Rheum Dis. 2019 Jan;78(1):83-90. doi: 10.1136/annrheumdis-2018-214104. Epub 2018 Oct 26.

  PMID: 30366945 BACKGROUND

• Niewald M, Muller LN, Hautmann MG, Dzierma Y, Melchior P, Graber S, Rube C, Fleckenstein J; working group "Benign diseases" of the DEGRO (German Society for Radiation Oncology). ArthroRad trial: multicentric prospective and randomized single-blinded trial on the effect of low-dose radiotherapy for painful osteoarthritis depending on the dose-results after 3 months' follow-up. Strahlenther Onkol. 2022 Apr;198(4):370-377. doi: 10.1007/s00066-021-01866-2. Epub 2021 Nov 1.

  PMID: 34724085 BACKGROUND

MeSH Terms

Conditions

Osteoarthritis, Knee; Joint Diseases

Interventions

Radiotherapy

Condition Hierarchy (Ancestors)

Osteoarthritis; Arthritis; Musculoskeletal Diseases; Rheumatic Diseases

Intervention Hierarchy (Ancestors)

Therapeutics

Study Officials

• Enrique Barrós, MD, MSc

  Universidad Rey Juan Carlos

  STUDY DIRECTOR

Central Study Contacts

Dolores Bedmar, MD, PhD

CONTACT

+34 916 006 325; mariadolores.bedmar@salud.madrid.org

Enrique Barrós, MD, Msc

CONTACT

+34 626 972 413; e.barros.2023@alumnos.urjc.es

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Physician and Surgeon; Geriatrician; Master's Degree in Pain Medicine

Model Details: All participants will receive the same standardized low-dose radiotherapy regimen. There is no comparator, control, or sham-treatment arm.

Study Record Dates

• First Submitted: October 14, 2026
• First Posted: October 21, 2026
• Study Start: October 15, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027
• Last Updated: October 21, 2026

Record last verified: 2026-10

Data Sharing

• IPD Sharing: Will not share

Locations

ES (4)