Fractures of the Shaft of the Femur- Winquist & Hansen Classification
There are two classification systems that are currently used for fracture of the femur. The AO Classification is of academic interest, used in research, and has minimal practical and clinical application. This particular classification may predict another injury. The Winquist & Hansen Classification is a system based on the extent of comminution and the amount of cortical contact between the fractured fragments in the shaft of the femur. It may have a value in early weightbearing and in the use of interlocking screws.
There are several different types in the Winquist & Hansen Classification. Type 0 indicates no comminution at the fracture site. Type I fractures are a small butterfly that covers less than 25% of the width of bone. Type II fractures are a larger butterfly that covers less than 50% of the width of the bone. Type III fractures are a large fragment of more than 50% of the width of the bone. The contact is a small spike. Type IV fractures are segmental comminution with no contact between the proximal and distal fragments. Types I and II of midshaft fractures are stable in length (axially stable) with good contact between proximal and distal fragments. Types III and IV are unstable in length and rotation. This classification is for traumatic fractures, not for pathological fractures or stress fractures. Axially stable fractures are more amenable to earlier weightbearing after IM rod.
Antegrade reamed IM rodding, statically locked to control rotation is the standard of care for femur shaft fractures, regardless of the type of the fracture. A piriformis entry site is preferred. The union rate is close to 98% with infrequent complications. Early stabilization of femur shaft fractures within 24 hours decreases complication such as fat embolism, pulmonary complication, and deep vein thrombosis (DVT). The physician should balance the risk in fixation of the fractured femur in head injured patients. Consider external fixation first then convert it to IM rodding within three weeks. Reaming is not recommended in patients with bilateral chest trauma. Reaming and ARDS is a controversial subject. At least two interlocking screws should be used in all fractures, one proximal and one distal. Oblique orientation of the proximal screws is preferred instead of transverse orientation, which could fail. For severe and segmental comminution, multiple interlocking screws proximal and distal should be considered. IM nailing releases IL-6 and IL-8. There are complications associated with the IM rodding of the femur. For example, in the supine position, there is an increased incidence of internal rotation deformity. The use of traction may lengthen the femur. A Pudendal nerve injury is another complication. Heterotropic ossification (HO) is the most frequent complication but is not clinically significant. Varus malunion can occur in trochanteric start point.
Winquist & Hansen classification remains to be a good communication tool between health professionals. It is easy to remember and signify the severity of the injury, the higher the number, the worse the injury, and it does not guide the clinician to the use of interlocking screws. The fracture classification may also change during surgery from a pre-existing undetected fracture or from an iatrogenic fracture.