From the Research
In a distal femur fracture, the deformity of varus and extension is primarily caused by the pull of the gastrocnemius muscle and the adductor muscles. The gastrocnemius, particularly its medial head which originates from the medial femoral condyle, exerts a strong posterior pull on the distal fragment, causing extension. Simultaneously, the adductor magnus, which attaches to the adductor tubercle on the medial epicondyle of the femur, pulls the distal fragment into varus (inward angulation). This combined muscular action creates the characteristic varus and extension deformity seen in distal femur fractures. The quadriceps muscle can also contribute to the extension component of the deformity by pulling on the proximal fragment. Understanding these muscle forces is crucial for proper reduction and fixation of distal femur fractures, as the surgeon must counteract these deforming forces to achieve and maintain anatomical alignment during treatment, as highlighted in recent studies 1. Some studies have investigated the treatment options for distal femur fractures, including the use of intramedullary nailing and plating 2, 3, but the primary cause of the deformity remains the muscular forces acting on the fracture fragments. The treatment of distal femur fractures should prioritize the correction of these deformities to improve patient outcomes and reduce the risk of complications, as discussed in the literature 4, 5. However, the most recent and highest quality study 1 supports the importance of understanding the muscular forces involved in the deformity. Key points to consider in the treatment of distal femur fractures include:
- The role of the gastrocnemius and adductor muscles in causing varus and extension deformity
- The importance of counteracting these deforming forces during reduction and fixation
- The need for careful consideration of treatment options, including intramedullary nailing and plating, to achieve optimal outcomes.