Stiffness and Low Dose Irradiation RCT
LDI TKR RCT
Treatment of Acquired Idiopathic Stiffness in Revision Total Knee Arthroplasty With Hinged Knee Prosthesis With or Without Low Dose Irradiation: A Multicentre Prospective Randomized Controlled Trial
1 other identifier
interventional
36
2 countries
4
Brief Summary
Acquired idiopathic stiffness (AIS) is a common complication following total knee arthroplasty (TKA). It is caused by excessive scar formation, which leads to pain, loss of motion, and functional impairment. When early noninvasive treatments fail, some patients require more surgery. In these cases, surgeons often use a special type of replacement called a hinged prosthesis, which allows more thorough removal of scar tissue and stiffened ligaments. Unfortunately, even after more surgery, many patients continue to struggle with stiffness, pain, and impaired function. Low-dose irradiation (LDI) is a safe, established therapy for conditions with abnormal scar formation. Its role in the setting of AIS has not been defined. The goal of this study is to compare outcomes of revision TKA with or without the addition of LDI. The primary outcome is range of motion at one year following surgery. Secondary outcomes include patient-reported functional scores, repeat surgeries, and complications like wound breakdown or infection. This project has the potential to address a common, debilitating complication after TKA, improve outcomes, reduce repeat interventions and healthcare costs, and broader implementation and standardization of care.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P25-P50 for not_applicable
Started Apr 2026
Typical duration for not_applicable
4 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
Study Start
First participant enrolled
April 1, 2026
CompletedFirst Submitted
Initial submission to the registry
August 11, 2026
CompletedFirst Posted
Study publicly available on registry
August 17, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
December 31, 2028
ExpectedStudy Completion
Last participant's last visit for all outcomes
January 31, 2029
August 17, 2026
March 1, 2026
2.8 years
August 11, 2026
August 11, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
Total arc of knee range of motion (ROM)
Goniometric measurement of total arc of motion (flexion minus extension deficit) performed by treating surgeon at each follow-up visit, per standard clinical protocol.
Baseline (pre-operative), intraoperative, 2 weeks, 6 weeks, 3 months, and1 year post-operatively.
Secondary Outcomes (8)
Oxford Knee Score (OKS)
Pre-op, 2 weeks, 6 weeks, 3 months, 1 year
EQ-5D-5L (health-related quality of life)
Pre-op, 2 weeks, 6 weeks, 3 months, 1 year
Visual Analogue Scale (VAS) - Pain
Pre-op, 2 weeks, 6 weeks, 3 months, 1 year
Patient Satisfaction (numeric rating)
6 weeks, 3 months, 1 year
Wound complications (requiring intervention)
2 weeks, 6 weeks, 3 months, 1 year
- +3 more secondary outcomes
Study Arms (2)
Hinged Revision TKA + Low-Dose Irradiation
EXPERIMENTALPatients undergo hinged revision total knee arthroplasty (TKA) with a rotating hinge prosthesis, followed by a single session of external beam low-dose irradiation (LDI) delivering 800 cGy to the operative knee on post-operative day 1 (or post-operative day 2 if medically necessary), coordinated with radiation oncology.
Hinged Revision TKA Alone
ACTIVE COMPARATORPatients undergo hinged revision total knee arthroplasty (TKA) with a rotating hinge prosthesis and receive standard postoperative care without low-dose irradiation. All perioperative care, rehabilitation, and follow-up protocols are identical to the experimental arm.
Interventions
A single session of external beam irradiation (800 cGy) delivered to the operative knee on post-operative day 1 (or post-operative day 2 if medically necessary). At Mount Sinai Hospital and Humber River Hospital, LDI is delivered at Princess Margaret Cancer Centre. US sites coordinate through local radiation oncology departments.
Full component revision to a rotating hinge knee prosthesis, including synovectomy, posterior capsule debridement, and release of fibrosed collateral ligaments, performed by the treating orthopaedic surgeon at each participating site.
Eligibility Criteria
You may qualify if:
- Adults (≥18 years) undergoing revision TKA with a hinged prosthesis for AIS after primary TKA
- Patient with a ROM arc \<70 degrees or flexion contracture of \>20 degrees without any identifiable cause for stiffness (e.g. component oversizing, malrotation, infection, or periprosthetic fracture).
You may not qualify if:
- Revision for causes other than AIS (e.g., component malposition, infection, periprosthetic fracture)
- Prior ipsilateral knee infection
- Revision to non-hinged prosthesis
- Medical contraindications to surgery
- Medical contraindications to irradiation
- Currently pregnant or planning to become pregnant during the study period
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (4)
University of Southern California
Los Angeles, California, 90007, United States
University of Utah
Salt Lake City, Utah, 84112, United States
Humber River Hospital
Toronto, Ontario, M3M 0B2, Canada
Mount Sinai Hospital
Toronto, Ontario, M5G 1X5, Canada
Related Publications (4)
Liow MHL, Flevas DA, Braun S, Nocon A, Lee GC, Sculco PK; TKAF Consortium. Rotating Hinge Revision Total Knee Arthroplasty Provides Greater Arc of Motion Gains for Patients Who Have Severe Arthrofibrosis. J Arthroplasty. 2025 Jan;40(1):198-202. doi: 10.1016/j.arth.2024.06.056. Epub 2024 Aug 9.
PMID: 39128782BACKGROUNDHaffar A, Goh GS, Fillingham YA, Torchia MT, Lonner JH. Treatment of arthrofibrosis and stiffness after total knee arthroplasty: an updated review of the literature. Int Orthop. 2022 Jun;46(6):1253-1279. doi: 10.1007/s00264-022-05344-x. Epub 2022 Mar 18.
PMID: 35301559BACKGROUNDLex JR, Entezari B, Backstein DJ, Wolfstadt JI. Reliable Outcomes Provided by a Rotating Hinge Knee Arthroplasty for Patients Who Have Moderate-To-Severe Arthrofibrosis. J Arthroplasty. 2026 Mar;41(3):862-868. doi: 10.1016/j.arth.2025.07.041. Epub 2025 Jul 24.
PMID: 40714210BACKGROUNDSchneider AM, Rice SJ, Lancaster N, McGraw M, Farid Y, Finn HA. Low-Dose Irradiation and Rotating-Hinge Revision for the Treatment of Severe Idiopathic Arthrofibrosis Following Total Knee Arthroplasty: A Review of 60 Patients With a Mean 6-Year Follow-Up. J Arthroplasty. 2024 Apr;39(4):1075-1082. doi: 10.1016/j.arth.2023.10.021. Epub 2023 Oct 18.
PMID: 37863275BACKGROUND
Study Officials
- PRINCIPAL INVESTIGATOR
Jesse Wolfstadt, MD, MSc
MOUNT SINAI HOSPITAL
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- NONE
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- PRINCIPAL INVESTIGATOR
- PI Title
- Division Head of Orthopaedic Surgery
Study Record Dates
First Submitted
August 11, 2026
First Posted
August 17, 2026
Study Start
April 1, 2026
Primary Completion (Estimated)
December 31, 2028
Study Completion (Estimated)
January 31, 2029
Last Updated
August 17, 2026
Record last verified: 2026-03
Data Sharing
- IPD Sharing
- Will not share
Individual participant data will not be shared publicly. De-identified aggregate data supporting the findings of this study will be available upon reasonable request to the corresponding author following publication of primary results.