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Not yet recruitingNCT07933523Updated Nov 12, 2026

LDRT Retreatment for Knee Osteoarthritis

A Phase 2 interventional study of Low Dose Radiation Therapy in Osteoarthitis and Osteoarthritic Knee Pain, sponsored by University of Wisconsin, Madison. Not yet recruiting at 1 site in United States. Open to participants aged 40 Years and older. Per ClinicalTrials.gov, last updated 2026-11-12.

Sponsored by University of Wisconsin, Madison · Phase 2, Interventional, and Treatment

Updated Nov 12, 2026Newly registeredGo to Updates ↓
Phase
Phase 2
Study type
Interventional
Enrollment
112
Allocation
Randomized
Ages
40 Years and older
Sex
All
01

Study summary

The goal of this clinical trial is to learn if one course of low-dose radiation therapy (LDRT) helps as much as two courses of LDRT in people with osteoarthritis.

The main questions it aims to answer are whether pain control, joint function, and quality of life are the same with one course of LDRT.

Participants will receive LDRT and can expect to be in the study for up to 3 months.

Read the detailed description

This study is being done to evaluate the degree of symptom improvement after dual-course low-dose radiation therapy (LDRT) compared to single-course LDRT in participants with osteoarthritis (OA) of the knee.

02

Conditions studied

  • Osteoarthitis
  • Osteoarthritic Knee Pain
03

In context

Lead sponsor

University of Wisconsin, Madison is the lead sponsor of 1,189 studies on the registry; 182 are open to participants now.

Of its 157 completed or terminated interventional studies of FDA-regulated products, 118 (75%) have results posted.

Browse University of Wisconsin, Madison studies →

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
40 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Clinical diagnosis of osteoarthritis of the knee
  • Age ≥40 years at the time of consent
  • Joint pain which has persisted for ≥3 months
  • Completed imaging of the involved joint in the past 3 months (including MRI, CT, X-ray, or bone scan)
  • Negative pregnancy test

Exclusion criteria

Exclusion Criteria:

  • Previous surgery to the affected joint or planned surgery to the affected joint in the next 6 months
  • Previous radiation treatment targeting the affected joint. Previous radiation targeting any other body site does not exclude from participation as long as there is no overlap, as determined at the discretion of the treating physician.
  • Current use of prescription medications containing opioids
  • Confirmed prior diagnosis of rheumatoid arthritis, pseudogout, or gout in the affected joint
Terms in these criteria, in plain language(1)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
112 participants (estimated)

Study arms

  • Experimental
    One course of LDRT

    Participants will receive one course of LDRT

    Radiation: Low Dose Radiation Therapy

  • Experimental
    Two courses of LDRT

    Participants will receive two courses of LDRT

    Radiation: Low Dose Radiation Therapy

Interventions

  • RadiationLow Dose Radiation Therapy

    Treatments will be given twice weekly over a duration of approximately 3 weeks.

06

What researchers measure

Primary outcomes

  1. Change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score - 6 months

    WOMAC is a 24 item questionnaire that evaluates pain, stiffness, and physical function in patients with hip or knee osteoarthritis. Typically rated using a 0 to 4 scale (0 = none, mild, moderate, severe, 4 = extreme), scores range from 0 to 96 points. Higher scores indicate worse symptoms and greater functional limitation.

    Time frame: Baseline to 6 months

Secondary outcomes

  1. Change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score - 9 months

    WOMAC is a 24 item questionnaire that evaluates pain, stiffness, and physical function in patients with hip or knee osteoarthritis. Typically rated using a 0 to 4 scale (0 = none, mild, moderate, severe, 4 = extreme), scores range from 0 to 96 points. Higher scores indicate worse symptoms and greater functional limitation.

    Time frame: Baseline to 9 months

  2. Change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score - 12 months

    WOMAC is a 24 item questionnaire that evaluates pain, stiffness, and physical function in patients with hip or knee osteoarthritis. Typically rated using a 0 to 4 scale (0 = none, mild, moderate, severe, 4 = extreme), scores range from 0 to 96 points. Higher scores indicate worse symptoms and greater functional limitation.

    Time frame: Baseline to 12 months

  3. Change in WOMAC pain sub-domain score

    Pain sub-domain has 5 items that evaluate pain in patients with hip or knee osteoarthritis. Typically rated using a 0 to 4 scale (0 = none, mild, moderate, severe, 4 = extreme), scores range from 0 to 20 points. Higher scores indicate worse pain.

    Time frame: Baseline to 12 months

  4. Change in WOMAC stiffness sub-domain score

    Stiffness sub-domain has 2 items that evaluate stiffness in patients with hip or knee osteoarthritis. Typically rated using a 0 to 4 scale (0 = none, mild, moderate, severe, 4 = extreme), scores range from 0 to 8 points. Higher scores indicate worse stiffness.

    Time frame: Baseline to 12 months

  5. Change in WOMAC joint function sub-domain score

    Stiffness sub-domain has 17 items that evaluate joint function in patients with hip or knee osteoarthritis. Typically rated using a 0 to 4 scale (0 = none, mild, moderate, severe, 4 = extreme), scores range from 0 to 68 points. Higher scores indicate greater physical limitations.

    Time frame: Baseline to 12 months

  6. Incidence of adverse events

    Evaluated by CTCAE, v6.0.

    Time frame: 6 months

  7. Change in use of pain relievers

    Participants will self-report how much and what pain relief medication they used while on study.

    Time frame: Baseline to 12 months

  8. Change in WOMAC score in one-joint treatment compared to two-joint treatment.

    WOMAC is a 24 item questionnaire that evaluates pain, stiffness, and physical function in patients with hip or knee osteoarthritis. Typically rated using a 0 to 4 scale (0 = none, mild, moderate, severe, 4 = extreme), scores range from 0 to 96 points. Higher scores indicate worse symptoms and greater functional limitation.

    Time frame: Baseline, 6 months, 9 months, 12 months

07

Study locations

1 site
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Timeline

1 registry update since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reached

Start is estimated for Jan 2027; primary completion for Jan 2033, 72 months later.

How these figures are worked out, and which studies are left out of them.

Registered
Nov 4, 2026
First posted
Nov 12, 2026
StartEst.
Jan 2027
Primary completionEst.
Jan 2033
CompletionEst.
Jan 2033
Last update
Nov 12, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
Registered
First appeared on the registry. No changes since
Nov 12, 2026
Show all 1 update
  1. Nov 12, 2026
    First appeared on the registry

From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗

10

Registry details

Key details

Study ID
NCT07933523
Lead sponsor
University of Wisconsin, Madison
Collaborators
Radiation Oncology Institute
Responsible party
Sponsor
First posted
Nov 12, 2026
Start date
Jan 2027 (estimated)
Primary completion
Jan 2033 (estimated)
Completion
Jan 2033 (estimated)
Last update
Nov 12, 2026

Study contacts

Marissa Weiss
Contact
marissa.weiss@wisc.edu
608-915-1201
Jessica Schuster, MD
principal investigator · University of Wisconsin, Madison

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.

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