Dr. Ebraheim’s educational animated video describes classifications of femoral neck fractures.
Femoral neck fractures can occur as a result of low energy trauma in the elderly. In this case you will need to get a medical consultation! Femoral neck fractures can also occur due to high energy trauma, such as with falls or motor vehicle accidents. Femoral neck fractures can occur in older as well as younger patients, and in these cases you need to apply the ATLS protocol. Femoral neck fractures can also occur due to insufficiency fractures. This occurs due to weak bones, because of osteoporosis or osteopenia. The patient will have groin pain, pain with axial compression and the x-ray may be normal (helpful in diagnosing insufficiency fracture). There may also be a stress fracture due to overuse and more loading on the hips. Stress fractures may occur in athletes, ballet dancers, or military recruits.
1. Subcapital – common
The subcapital fracture has two classifications: the garden classification and Pauwel’s classification. The garden classification system classifies the fracture according to the amount or degree of displacement. It relates the amount of displacement to the risk of vascular disruption. This classification applies to the geriatric and insufficiency fractures. It can then be classified into two groups: the nondisplaced and the displaced. Types I and II are nondisplaced, while types III and IV are displaced. Type I is incomplete and impacted in valgus. Type II is a complete fracture and nondisplaced on at least two planes (anteroposterior & lateral). Type III is a complete fracture and partially displaced. The trabecular pattern of the femoral head does not line up with the acetabular trabecular pattern. A type IV fracture is completely displaced with no continuity between the proximal and distal fragments. The trabecular pattern of the femoral head remains parallel with the acetabulum trabecular pattern.
The Pauwel’s Classification is classified into three fracture types. It classifies the fracture according to the orientation and direction of the fracture line across the femoral line. It related to the biomechanical stability. The more vertical the fracture, the more sheer forces and the more the complication rate. Type I is stable and has an obliquity ranging from 0-30 degrees. Type II is less stable and have an obliquity ranging from 30-50 degrees. Lastly, type III is unstable and has an obliquity between 50-70 degrees or more. As the fracture progresses from Type I – Type III, the obliquity of the fracture line increases. As the fracture line becomes more vertical, the sheer forces increase and the instability increases. A horizontal fracture is good and stable while a vertical fracture is bad and unstable. The more displaced the fracture, the more disruption of the blood supply and the chance of avascular necrosis and nonunion (can occur in about 25% of displaced fractures). In nonunion occurs in a younger patient, you may help the patient by doing a subtrochanteric osteotomy to reorient the fracture line from vertical to horizontal (will help the fracture healing).
Femoral Neck Fractures Associated with Femoral Shaft Fractures
The typical neck fracture is vertical and nondisplaced. It may require internal rotation view x-rays to see this hip fracture (fracture could be missed). Treatment of this fracture is to fix the femoral neck fracture first, followed by the femoral shaft fracture. The usual combination is parallel screws in the femoral neck and a retrograde femoral rod for the fractured femur.
Stress fractures are more common in females due to the female athletic triad. It can be a tension fracture. The fracture or callus is present on the superior aspect of the femoral neck. Adult bone is weak in tension, so stress fracture of the femoral neck needs to be fixed! This should be an emergency operation before the fracture displaces. With compression fractures, the compression or callus is present on the inferior aspect of the femoral neck. It is believed that if the compression fracture is less than 50% across the neck, then the fracture could be stable and you can do protected crutch ambulation. If the fracture is more than 50% across the neck, then the fracture is unstable and you will do an ORIF. Some surgeons fix all stress fractures of the femoral neck. A female runner with groin pain can indicated a stress fracture. Get an MRI, the fracture will probably need to be fixed.
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