Periprosthetic Distal Femur Fracture

Treatment of Periprosthetic Distal Femur Fractures: A Randomized Controlled Trial of Locking Plate Osteosynthesis Versus Retrograde Nailing

A periprosthetic distal femur fracture is a fracture close to a knee implant. This type of fracture is often difficult to fix because of the close proximity of the two surgical implants which can sometimes interfere with proper bone healing. Improper healing can cause significant impairment and sometimes requires additional surgeries to correct the problem. Despite considerable interest and research put into developing techniques to repair this fracture surgeons do not know which is the best way to treat this type of fracture. Our multicentre orthopaedic study group is conducting this study to compare two standard, but different treatments for periprosthetic distal femur fractures. One treatment consists of open surgery and the placement of a plate and screws along the side of the femur. The other consists of implanting an intramedullary nail in the femur. The goal of this study is to directly compare the two treatments to see if one treatment results in better patient outcomes than the other.

A direct lateral approach to the distal femur will be employed utilizing minimally invasive and indirect reduction techniques. After fracture reduction is achieved with the use of intra-operative fluoroscopy, a locking plate will be provisionally implanted. Following confirmation of placement, definitive fixation will follow with multiple locking screws in the distal fragment and bicortical screw fixation proximally. A standard layered closure will follow

The previous midline knee incision will be employed to access to the knee joint, allowing exposure of the femoral start point via the open box in the femoral component. Following reaming of the canal, an appropriately sized retrograde nail will be inserted. Intra-operative fluoroscopy will be used to confirm reduction. Both proximal and distal locking screws will be used to transfix the nail. A standard layered closure will follow.

The TUG is a very simple timed test that was introduced in 1991 to measure mobility in the elderly. It involves documenting the time, in seconds, taken for subjects to rise from a standard arm chair, walk to a line on the floor 3 meters away, turn, return, and sit down again

INCLUSION CRITERIA: Age 18 years and older Displaced periprosthetic fracture of the distal femur Fracture amenable to both treatment groups, in the opinion of the investigator Knee prosthesis is well-fixed and non-stemmed Open box femoral component Provision of written informed consent EXCLUSION CRITERIA: Presence of an active infection around the fracture (soft tissue or bone) Open fracture Injury Severity Score (ISS) > 15 or any associated major injuries of the lower extremities Medical contraindication to surgery Pregnant women Likely problems, in the judgment of the investigators, with maintaining follow-up

Claireaux HA, Searle HK, Parsons NR, Griffin XL. Interventions for treating fractures of the distal femur in adults. Cochrane Database Syst Rev. 2022 Oct 5;10(10):CD010606. doi: 10.1002/14651858.CD010606.pub3.