Single vs. Dual Implant Fixation for Distal Femur Fractures in Older or Compromised Adults

The Investigators aim to conduct a multi-centre, preliminary RCT to determine the feasibility and inform the design of a definitive trial comparing patient-important outcomes between patients aged 40 years and older with distal femur fractures managed with SIF vs. DIF.

Primary Aim: Evaluate the feasibility of conducting a larger, definitive trial examining outcomes following SIF vs. DIF for DFFs in older or compromised adults. Our primary outcomes for this objective will be 1) recruitment and retention at the participating sites; and 2) site investigator feedback regarding barriers to protocol adherence.

Secondary Aims: Pilot the collection of candidate outcome measures to determine the optimal primary end point and sample size for a definitive trial. Our primary outcome for this objective will be the Oxford Knee Score, and secondary outcomes will include a range of patient-reported quality of life (QOL) measures, and objective clinical measures.

In addition, the study includes an ultrasound sub-study aimed at evaluating the feasibility of using ultrasound imaging to monitor bone healing and detect complications like non-union in patients with DFF.

Participants will be randomly assigned to receive either SIF or DIF, with SIF generally involving a single implant (such as a lateral locked plate or retrograde intramedullary nail) and DIF using a combination of implants (e.g., dual plates or a nail and plate). This randomized design will enable us to assess whether dual implant fixation offers improved clinical outcomes, such as reduced morbidity and faster weight-bearing recovery, compared to the more traditional single implant fixation.

Non-Randomized Participation: The investigators will collect data surrounding the number of eligible patients approached for consent, eligible patients not approached for consent and reason why, along with the proportion of patients who do not consent and reasons why to refine our strategy for the definitive trial. For patients who are excluded due to a lack of clinical equipoise, the investigators will provide the option of participating in a concurrent cohort study.This study will record the same variables as the RCT.

The trial will take place at four major trauma centers across Canada: London Health Sciences Centre - Victoria Hospital, St. Michael's Hospital, Sunnybrook Health Sciences Centre, and Alberta Health Services Centre. Participants will receive follow-up visits at these centers, which will include clinical check-ups, rehabilitation sessions, and imaging assessments to track their recovery progress.

The data gathered from this feasibility study will provide critical insights into the practicality of a larger-scale trial and will help inform future treatment strategies for distal femur fractures.

Inclusion criteria

• Isolated DFF (native AO/OTA-type A2, A3, C or periprosthetic Lewis and

Rorabeck type 1, 2) and either:

• Age ≥ 60 years or;
• Age 18-60 years with one or more of:

i. Osteoporosis ii. Obesity (Body Mass Index >30) iii. Metaphyseal comminution iv. Diabetes

• Fracture amenable to plating and nailing
• Ability to read and speak English or availability of a translator
• Acute fractures (within 14-days of injury)
• No surgeon preference regarding SIF vs. DIF
• Provision of informed consent

Exclusion criteria

• Candidate for primary or revision arthroplasty (surgeon opinion)
• Periprosthetic fracture with loose implant
• Gustillo grade III open fractures
• Ipsilateral hip implant
• Likely problems, in the judgment of the investigators, with maintaining follow-up (i.e., no fixed address, mentally competent to give consent, etc.)
• Non-ambulatory patients
• Multi-trauma patient (Injury Severity Score ≥ 16)
• Lack of bone substance or poor bone-quality which, in the surgeon's judgment, makes fixation impossible
• Any concomitant lower-extremity injury
• Inability to obtain informed consent due to language barrier