Far Cortical Locking Versus Standard Constructs for Distal Femur Fractures

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

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.

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

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