Femoral Neck Fractures

There are three broad mechanisms which can cause femoral neck fractures:

Traumatic fractures

Traumatic fractures or breaks of the femoral neck have a bimodal distribution meaning they arise in two distinct patient populations:

• The first population is elderly patients who have osteoporosis or age-related bone weakening. These patients are the most susceptible to breaking the femoral neck from a fall which can be as simple as stepping off a sidewalk or falling while in the shower.
• Femoral neck fractures can also occur during high-energy trauma which is more common in the younger population. High-energy trauma includes injuries from car accidents or sporting injuries that result in a direct force to the femoral neck.

Atypical Femoral Fractures

It should be noted that there is a subcategory of femoral fractures called “atypical” femoral fractures where the bone of the femoral neck is weakened more than would be expected. Examples of bone weakening conditions include:

1. Presence of a malignant tumor
2. Bone conditions such as Paget’s disease
3. Osteoporosis
4. Bisphosphonate medications: These are medications used for osteoporosis that have a risk of rendering the femoral neck brittle and more susceptible to fracture

Stress fractures

Stress fractures of the femoral neck can also be seen in patients that load the bone too harshly with repetitive stress. Examples of this include patients that are quickly ramping up their activities such as training for a marathon. These stress fractures can happen in patients who rapidly accelerate the increase of activity over a relatively short duration of time thereby overloading the bone.

The symptoms of a femoral neck fracture are quite consistent. In the acute setting, symptoms include sudden, severe hip and groin pain after a fall or traumatic accident. In the chronic setting, symptoms can be less pronounced but groin pain and the gradual inability to bear weight are classic. Because of the fracture, the leg may appear shortened compared to the other side and turned outward in external rotation. With associated soft tissue damage around the hip, there may be visible swelling or bruising on the leg.

The diagnosis of a femoral neck fracture relies on a combination of a proper history, physical exam, and interpretation of the imaging findings:

1. Paying attention to the patient’s history is extremely important because groin pain that develops in a non-traumatic way that is not attributed to a degenerative arthritic condition is very concerning for an atypical femoral neck fracture such as a developing stress fracture.
2. The physical exam is important to confirm the presence of the fracture with a shortened and externally rotated extremity compared to the contralateral side. In addition, in the traumatic setting, it is essential to rule out associated injuries such as a distal femur fracture and to confirm the pulses, motor function, and sensation in both lower extremities. There will be limited motion of the femoral head with pain on any attempted rotation or pressure on the hip joint.
3. Imaging modalities
   • On imaging, X-rays will usually confirm the fracture but full-length X-rays of the entire femur are required during the workup. It is essential in traumatic injuries of the femoral neck that X-rays of the entire femur be obtained because in 10-15% of femoral neck fractures, there is also an associated fracture of the femoral shaft.
   • In some cases, X-rays may not show the fracture clearly especially in non-displaced femoral neck fractures or atypical femoral neck fractures where the femoral neck has not shifted out of place. In these less obvious cases, an MRI or CT scan may be utilized. MRIs are very helpful for detecting stress or fractures by uncovering edema in the bone before an obvious fracture is visible on radiographs. A CT scan is useful for surgical planning in borderline femoral neck fractures but a CT scan is not required in all cases especially where there is an obviously displaced femoral neck fracture.

When surgery is not an option:

• It is very rare that if a patient truly has a femoral neck fracture that we would treat it without surgery. Nonsurgical treatment may be considered for either very stable and non-displaced fractures where the fracture line can heal in its current position or in patients who are too medically frail to undergo the anesthesia required for surgical intervention.
• However, because nonsurgical treatment of these fractures involves bed rest with limited weight bearing as the fracture heals, it carries the consequences of prolonged immobilization such as bed sores, urinary tract infections, blood clots, and pulmonary embolism which can further worsen a patient’s overall health.

Surgery for non-displaced fractures:

• Due to the significant medical risks of nonsurgical treatment, for all patients who are able to undergo surgery, surgical intervention is recommended. Ideally, surgery should be done within 48 hours of the injury and the patient should be medically optimized by a multidisciplinary team in the hospital. The quicker a patient can undergo surgery for their femoral neck fracture in a safe and medically optimized way, the less complications they will incur.
• The specific type of surgery recommended depends on the type of fracture the patient suffers and how much displacement there is. For non-displaced fractures, closed reduction of the fracture and percutaneous screw placement is satisfactory to stabilize the bone to allow for fracture healing. Percutaneous screws are screws placed through small incisions made through the skin to secure the fracture.

Surgery for displaced fractures:

• In younger patients who have a small amount of displacement, an open reduction to restore the anatomy of the femoral neck with a plate and screw fixation construct is often indicated to help stabilize the bone without needing a formal surgical reconstruction of the hip joint.
• However, for femoral neck fractures that are significantly displaced in the elderly population, open reduction and internal fixation with a plate and screw construct is not advised because the blood supply to the femoral head is so delicate. If elderly patients undergo an open reduction and internal fixation that fails, they are at higher risk for further complications down the road.
• Instead, a joint replacement is the most durable option to restore stability, reduce pain, and allow for early mobility when there is a displaced femoral neck fracture in the elderly population. Joint replacement can be in the form of a hemiarthroplasty where the acetabular socket is left alone and just the femoral head is replaced with a prosthesis. This is an excellent option in older patients who do not have any pre-existing hip arthritis and would be the standard of care in patients who are unable to reliably follow post-surgery restrictions such as those with dementia or have spasticity disorders (ex. Parkinson’s). On the other hand, total hip replacement, which involves replacing both the acetabular socket as well as the femoral head, can be considered in patients who have pre-existing hip arthritis and who can reliably follow post-surgery restrictions. A total hip replacement can also be considered in highly active patients.

Expected rehabilitation:

• Regardless of the type of treatment that is undertaken, extended rehabilitation is essential to a satisfactory recovery. Patients will work with physical therapy during their inpatient stay and after the patient has been discharged from the hospital, they will usually require a short stay in either inpatient rehab or at a skilled nursing facility to regain their mobility back.
• A common question from patients and their families is how long recovery will take after hip fracture surgery. This amount of time varies depending on the surgery undertaken and the patient’s health prior to surgery. Nonetheless, most patients begin walking with assistance within days of surgery and continue their rehabilitation for several months afterward.
• We always counsel patients who suffer from a femoral neck fracture that returning to the exact same level of activity may not be possible. Nonetheless, the ultimate goal of surgery and post-surgery rehabilitation is to improve our patients’ mobility as close to their pre-morbid state as we safely can. Most patients are able to regain independence and comfort in walking again.