far cortical locking versus standard constructs for distal femur fractures

Conditions: Distal Femur Fracture

Summary: 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

Keywords: distal femur locking screw fracture healing