DIFFIR - Geriatric Distal Femur Fixation Versus Replacement

The current standard of care for most intra-articular distal femur fractures (above the knee joint) in geriatric patients is a surgical fixation using plates and screws to hold the fracture pieces in the correct position, until the fracture as healed.

However, surgical fixation of these complex fractures in geriatric patients, is associated with significant complications, such as non-union (when the broken bone does not heal properly), infection and the need for revision surgery. Additionally, surgical fixation requires prolonged immobilization of of the affected limb (typically around 6-12 weeks post-operatively), which can lead to disability and other complications. Geriatric patients, especially those frail and with cognition impairment, are unable to adhere to the immobilization restrictions, which leads to an increased risk of fixation failure (broken bone does not heal).

Another treatment option for those patients is an acute distal femoral replacement (artificial knee), where damaged parts of the knee joint are replaced with artificial prosthesis. This procedure allows patients to walk immediately after the surgery and faster return to previous level of function, therefore avoiding the complications for immobilization.

There is a lack of guideline and evidence to suggest which surgical technique is best to provide superior function outcomes, lower complications and reduced costs. The proposed study seeks to answer this question by performing a large clinical trial comparing knee replacement versus surgical fixation in geriatric patients with distal femur fracture.

The proposed study is a prospective, randomized controlled trial, involving multiple centers across North America, to compare distal femur replacement (knee prosthesis) versus surgical fixation as a treatment for geriatric distal femur fracture.

Patients 65 years of age and older, with closed, displaced ( when the two ends of the bone are not lined up straight), comminuted (bone is in many pieces) distal femur fracture, who meet the inclusion criteria and agree to participate in the study, will be randomly assigned (by chance like flipping a coin) to receive either acute distal femoral replacement or surgical fixation.

The hypothesis is that patients in the acute distal femoral replacement group will have superior function, range of motion (full movement potential of a joint), general health status, reduced pain, and lower complications when compared to patients in the surgical fixation group.

Eligibility Criteria:
Inclusion Criteria:

* Male and female patients
* 65 years and older
* Isolated fracture of the distal femur (Classification 33)
* Fracture is amendable to both treatments
* Fracture is acute (within 2 weeks from time of injury)
* Patient was ambulatory (with or without walking aids) prior to the injury
* Independent or moderately frail with score of 3 to 6 on the Clinical Frailty Scale
* Patient is able to read and understand English, French, or Spanish
* Patient or substitute decision maker is able to provide written informed consent to participate in the study

Exclusion Criteria:

* Active or previous infection around the fracture (soft tissue or bone)
* Open fracture
* Bilateral femur fractures
* Major vascular injuries requiring intervention, compartment syndrome and major neurologic injuries
* Pathological fracture excluding osteoporosis
* Previous surgical fixation or total knee replacement of the distal femur or proximal tibia
* Previous surgical fixation or hemi/total replacement of the hip
* Current or previous extensor mechanism (patellar tendon, quadriceps tendon, or patella fracture) disruption or repair
* Polytrauma (Injury Severity Score \> 15) or any associated major injuries of the lower extremities
* Previous medical diagnosis of dementia
* Medical or surgical contra-indication to surgery