Far Cortical Locking Versus Standard Constructs for Distal Femur Fractures

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

Eligibility Criteria:
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