pDIFFIR: Geriatric Periprosthetic DIstal Femur: FIxation Versus Replacement (pDIFFIR)

pDIFFIR: Geriatric Periprosthetic DIstal Femur: FIxation Versus Replacement - A Randomized Controlled Trial of Acute Open Reduction Internal Fixation (ORIF) Versus Distal Femur Replacement (DFR)

Periprosthetic distal femur fractures are a significant source of morbidity and mortality for elderly patients. One treatment option involved a surgical fixation with plates or nails, screws and cables/wires along the side of your fractured bone. The second method consists in replacing your knee joint with an artificial knee prosthesis (artificial knee joint).

The primary objective is to determine if acute distal femur replacement improves knee pain and functional outcomes compared to surgical fixation. Secondary outcomes are mortality, reoperation, complications, post-operative pain and quality of life. A health economic analysis will be conducted to assess the cost-effectiveness of both treatments.

A total of 148 patients (74/group) will be enrolled in the study.

Study Overview

• Status: Recruiting
• Conditions: Knee Fracture; Distal Femur Fracture; Periprosthetic Fracture Around Prosthetic Joint Implant Knee
• Intervention / Treatment: Procedure: Distal Femur Replacement; Procedure: Surgical fixation

• Study Type: Interventional
• Enrollment (Estimated): 148
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Cassandra Tardif-Theriault; Phone Number: 77117 416-864-6060; Email: cassandra.tardif-theriault@unityhealth.to

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5B 1W8
      • Recruiting
      • St. Michael's Hospital
      • Principal Investigator: Amir Khoshbin, MD
      • Contact: Cassandra Tardif-Theriault; Phone Number: 77117 416-864-6060; Email: cassandra.tardif-theriault@unityhealth.to

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 65 years and older (Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• • 65 years and older

  • Isolated periprosthetic fracture of the distal femur around a stable primary total knee arthroplasty (Lewis and Rorabeck Type 1-2)
  • Fracture is acute (within 1 week from time of injury)
  • Patient was ambulatory (with or without walking aids) in the community and at home prior to the injury
  • Independent or moderately frail with score of 3 to 6 on the validated Clinical Frailty Scale
  • Patient is able to read and understand the consent form document, or an interpreter is available to the patient at the time of consent and follow-up
  • Patient or substitute decision maker is able to provide written informed consent to participate in the study

Exclusion Criteria:

• • Active infection around the fracture (soft tissue or bone)

  • Open fracture
  • Bilateral femur fractures
  • Major neuro-vascular injury requiring intervention, compartment syndrome and major neurologic injuries
  • Pathological fracture excluding osteoporosis
  • Ipsilateral total knee arthroplasty using revision components (varus/valgus constraint, stemmed femoral components)
  • Periprosthetic distal femur fracture around a loose or failing primary total knee arthroplasty (Lewis and Rorabeck Type III)
  • Ipsilateral primary partial knee or patellofemoral arthroplasty
  • Previous ORIF of the distal femur or proximal tibia or patella
  • Current or previous extensor mechanism (patellar tendon, quadriceps tendon, or patella fracture) disruption or repair
  • Poly-trauma status (Injury Severity Score>15) or any associated major injuries of the lower extremities that may hinder post-operative ambulation
  • Medical contraindication to surgery

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Group A - DFR	Procedure: Distal Femur Replacement; Knee surgery to remove the lower part of the femur and knee joint (where the broken bones are) and will replace them with an artificial knee joint (prosthesis).
Active Comparator: Group B - ORIF	Procedure: Surgical fixation; Knee surgery to fix the fracture, that can use wires, nails, screws, pins or plates to health and fix the bones together.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Knee function	Compare knee pain between the two groups using the Oxford Knee Score - which is a patient reported outcome measure. It assess knee function and gives a rating from 0 to 48 - being 0 bad knee function and 48 - excellent knee function.	12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mortality	Track patient's death.	24 months

Collaborators and Investigators

• Sponsor: Unity Health Toronto
• Collaborators: Mount Sinai Hospital, Canada
• Investigators: Principal Investigator: Amir Khoshbin, MD, Unity Health Toronto - St Michael's Hospital; Principal Investigator: Jesse Wolfstadt, MD, Mount Sinai Health Hospital

Study record dates

Study Major Dates

• Study Start (Actual): October 17, 2025
• Primary Completion (Estimated): December 10, 2030
• Study Completion (Estimated): December 10, 2032

Study Registration Dates

• First Submitted: March 28, 2023
• First Submitted That Met QC Criteria: March 28, 2023
• First Posted (Actual): April 10, 2023

Study Record Updates

• Last Update Posted (Actual): December 18, 2025
• Last Update Submitted That Met QC Criteria: December 10, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Knee replacement; Surgical fixation; Geriatric patients; Periprosthetic Distal Femur fracture
• Additional Relevant MeSH Terms: Wounds and Injuries; Leg Injuries; Fractures, Bone; Femoral Fractures; Knee Injuries; Femoral Fractures, Distal; Knee Fractures; Surgical Equipment; Equipment and Supplies; Surgical Fixation Devices
• Other Study ID Numbers: 23-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No