Distal femur fractures occur when the thighbone (femur) breaks just above the knee joint. These fractures are more common in older individuals with weaker bones. In younger patients, these fractures can result from high-energy impacts like car crashes, often leading to breaks that extend into the knee joint and shatter the bone into multiple pieces.
The knee is the largest weight-bearing joint in the body. The lower part of the thigh bone (femur) forms the upper part of the knee joint, while the top part of the shinbone (tibia) supports the lower part of the knee joint. The ends of the femur are covered with a smooth surface called articular cartilage, which cushions the bone and facilitates knee movement.
Types of Distal Femur Fractures
Symptoms are typically felt around the knee joint and may extend to the thigh area. Common symptoms include:
Distal femur fractures typically occur for different reasons in younger patients (under 50) and the elderly. In younger patients, high-energy impacts such as falls from heights or car accidents often result in fractures. These fractures can sometimes be accompanied by other injuries due to the forceful nature of the impact. In the elderly, weakened and fragile bones due to degeneration can lead to distal femur fractures even with lower-force injuries, like a fall from standing.
Distal femur fractures are confirmed through X-rays to assess the severity of the injury and any related damage. Compound injuries necessitate surgical intervention to ensure proper treatment and stability. Surgery is crucial to minimise the risk of infection, which can lead to further complications and hinder the bone’s healing process. A procedure commonly used for treating compound injuries is Open Reduction and Internal Fixation, which will be described below.
Internal fixation methods include:
Both of these methods can be performed through a single larger incision or multiple smaller ones, depending on the type and severity of the fracture.
If the fracture has fragmented the bone into many small pieces above the knee joint, it is generally not pieced back together. Instead, a plate or rod will be fixed at both ends of the fracture without directly repositioning the numerous small fragments in between. This strategy preserves the bone’s natural shape and length while it heals. Over time, these individual fragments naturally fuse into new bone, forming a callus.
In cases where the fracture may heal slowly, such as in elderly patients with poor bone quality, a bone graft may be used to facilitate the formation of the callus. These grafts can be obtained from the patient themselves, usually taken from the pelvis, or from cadaver bone sourced from a tissue or bone bank. Alternatively, artificial bone fillers can also be used.
In more severe instances, when the fracture is too complicated and the bone quality is too poor to repair, the fragments are removed and the bone is replaced with a knee replacement implant.
To learn more about the fracture fixation procedure, as well as what you can expect prior to, during, and after the surgery, please visit our Fracture Fixation page.