A Femur Shaft occurs with a break of the thigh bone (the femur). Medically known as a Femoral Shaft Fracture, the shaft of the femur refers to any part of this long bone between right under the hip joint to just above the knee joint as the femur begins to widen. This area of the thigh bone is called the diaphysis, or middle of the femur. When the very top portion of the femur, the head or neck of the femur, is broken, this is considered a hip fracture. If the femur is broken at the lower end, the part that articulates with the knee joint, this will be considered a knee fracture. A femoral shaft fracture is managed and treated very differently than a hip or knee fracture.

A common tool used to categorize a femoral shaft fracture is the Winquist and Hansen Classification System. This system classifies a femoral shaft fracture based on the amount of comminution of the bone. A comminuted fracture is one in which the bone is broken in two or more places. The classification types are:

• Type 0: no comminution
• Type II: a small butterfly fragment that covers less than 25% of width of the bone. A butterfly fragment refers to a break in a bone in two oblique lines that meet forming a wedge piece of bone, resembling the wings of a butterfly
• Type III: larger butterfly fragment, covering up to 50% width of the bone
• Type IV: comminuted break with a large butterfly fragment of greater than 50% width of the bone
• Type V: severe comminution of the femoral shaft