Far Cortical Locking Versus Standard Constructs for Distal Femur Fractures

Study Overview
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Brief Summary
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To determine if Far Cortical Locking screws increase fracture healing rates at 3 months in Closed Distal Femur Fractures in adults when compared to Standard screw constructs. Fracture healing at 3 months will be assessed via radiographic and clinical assessment of the fracture. Null Hypothesis: There will be no difference in fracture healing at 3 months post-fixation between subjects treated with far cortical locking screw or standard screw fixation.

Detailed Description
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A multicentre randomized controlled trial with a sample size of 138 subjects. Primary Outcome is fracture healing at 3 months via radiographic and and clinical assessment. Radiographic healing will be defined as bridging of one or more cortices as seen on x-ray. Radiographic assessment will be centrally adjudicated by a committee of three study investigators. Clinical healing will be assessed using the Function Index for Trauma (FIX-IT). Secondary outcome measurements will include patient-reported quality of life and CT quantification of fracture callus volume. Quality of life will be measured with the Short-Form 36 Version 2 (SF-36) instrument at all follow-up intervals. A CT scan of the fracture site will be performed at the 3 month follow-up. Using a quantitative protocol the volume of callus will be measured and the extent of cortical bridging will be assessed. Additional secondary outcomes include radiographic and clinical healing, as well as patient-important complications. These will include adverse events, delayed union (>6 months), non union (failure for fracture healing to progress on serial x-rays between 6 and 9 months), malalignment (>5 degrees), hardware failure, infection, and reoperation. Information surrounding the type of complication, duration, management and/or treatment of all complications will be recorded A Data Safety Monitoring Board will be established to independently monitor trial data. Specific inclusion criteria: Men or women ages 18 years or older Displaced distal femur fracture (OTA 33A or 33C) as seen in radiographs Planned treatment using a distal femur locking plate Ability to read and speak English or availability of translator willing to assist with completion of study forms Fractures < 14 days post injury Provision of informed consent Specific exclusion criteria: Open distal femur fracture requiring flap or vascular repair (grade 3b or 3c) Planned fixation strategy includes interfragmentary lag fixation of non-articular fractures Active local infection Limited life expectancy due to significant medical co-morbidity or medical contraindication to surgery Inability to comply with rehabilitation or form completion Likely problems, in the judgment of the investigators, with maintaining follow-up (i.e. patients with no fixed address, patients not mentally competent to give consent, etc.) Non-ambulatory patients Lack of bone substance or poor bone quality which, in the surgeon's judgment, makes locked plate fixation impossible Periprosthetic fractures Any concomitant lower-extremity injury that requires non-weight-bearing beyond 6 weeks post-operative Addition of bone graft, bone graft substitute or BMP Pregnant women

Official Title
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A Multicentre, Randomized Trial of Far Cortical Locking Versus Standard Constructs for Acute, Displaced Fractures of the Distal Femur Treated With Locked Plate Fixation

Conditions
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Distal Femur Fracture

Intervention / Treatment
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* Device: Far Cortical locking screw fixation
* Device: Standard screw fixation


Participation Criteria
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Eligibility Criteria
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Specific inclusion criteria: Men or women ages 18 years or older Displaced distal femur fracture (OTA 33A or 33C) as seen in radiographs Planned treatment using a distal femur locking plate Ability to read and speak English or availability of translator willing to assist with completion of study forms Fractures < 14 days post injury Provision of informed consent Specific exclusion criteria: Open distal femur fracture requiring flap or vascular repair (grade 3b or 3c) Planned fixation strategy includes interfragmentary lag fixation of non-articular fractures Active local infection Limited life expectancy due to significant medical co-morbidity or medical contraindication to surgery Inability to comply with rehabilitation or form completion Likely problems, in the judgment of the investigators, with maintaining follow-up (i.e. patients with no fixed address, patients not mentally competent to give consent, etc.) Non-ambulatory patients Lack of bone substance or poor bone quality which, in the surgeon's judgment, makes locked plate fixation impossible Periprosthetic fractures Any concomitant lower-extremity injury that requires non-weight-bearing beyond 6 weeks post-operative Addition of bone graft, bone graft substitute or BMP Pregnant women

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Far Cortical Locking screw fixation<br>Far Cortical Locking screw fixation | Device: Far Cortical locking screw fixation<br>* Standard screw fixation<br>|
| Active Comparator: Standard screw fixation<br>Standard screw fixation | Device: Standard screw fixation<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Composite fracture healing | Radiographic fracture healing defined as bridging of 1 or more cortices. Clinical fracture healing assessed with FIX-IT. Using the win ratio method, we hierarchically assessed radiographic healing, followed by clinical fracture healing. The pairwise comparison proceeds in a hierarchical fashion, using radiographic healing, followed by the FIX-IT score when patients cannot be differentiated based on radiographic healing. For each pairwise comparison, the treatment groups are assigned a win, loss, or tie. We calculate the win ratio as the number of wins in the FCL screw treatment group divided by the number of wins in the Standard screw group. | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Radiographic healing | Union is defined as the bridging of 1 or more cortices with stable fixation by three months post-fixation. | 3 months | 
| Clinical healing | We assessed clinical fracture healing using the Function Index for Trauma (FIX-IT) score. The FIX-IT instrument quantifies clinical healing by aggregating a 0- to 6-point assessment of weight-bearing and fracture site pain for a maximum score of 12 points, indicating the highest level of functional healing. | 3 months | 
| Patient-reported health-related quality of life | Assessment of SF-36 scores (physical component and mental component) | 3 months | 
| Patient-reported health-related quality of life | Assessment of SF-36 scores (physical component and mental component) | 12 months | 
| CT quantification of fracture callus volume | Using a quantitative protocol, the volume of callus will be measured. | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Distal, Femur, Locking, Screw, Fracture, Healing