What is Femoral Neck Fractures?
Hip fractures are common, particularly among the elderly who visit emergency rooms. They can also occur in younger athletes or individuals involved in significant traumatic events. Quick identification and treatment of these injuries are necessary to avoid severe complications in the hip joint. In fact, hip fractures result in a significant financial strain in the United States, being among the top 20 most costly conditions to manage. Roughly 20 billion dollars are spent annually on treating these injuries. Forecasts suggest that by 2030, there could be around 300,000 instances of hip fractures every year in the US.
One particular type of hip fracture is a femoral neck fracture, which happens inside the hip joint. The femoral neck is the connecting part between the long part of the femur (thigh bone) and the spherical top part of the bone that fits into the hip socket. Its position makes it highly susceptible to fractures. When there’s a displaced fracture, the blood supply to the top part of the femur, which travels along the femoral neck, becomes a crucial factor to consider.
What Causes Femoral Neck Fractures?
Femoral neck fractures, or breaks in the part of the thigh bone just below the ball of the hip joint, often happen when elderly people have low-energy falls. However, in younger people, these fractures are usually due to high-energy injuries, like falling from a great height or car accidents.
Several risk factors can increase the chances of experiencing a femoral neck fracture. These include being female, having reduced movement capability, and low bone density.
Risk Factors and Frequency for Femoral Neck Fractures
About 1.6 million hip fractures are recorded every year. Women account for 70% of these cases. As people get older, the risk of experiencing a hip fracture greatly increases. White females have been noted to typically have a higher risk of suffering from a hip fracture.
Signs and Symptoms of Femoral Neck Fractures
Most patients with a hip fracture have recently experienced some form of trauma. However, in patients with dementia or cognitive impairment, it may not be clear as they may not report any injury. In such cases, healthcare assistants or nursing home staff can provide valuable information, such as reports of recent falls or changes in mental status over the last few days. Patients typically complain of hip pain and limited movement range. A hip fracture doesn’t always cause visible changes, but if the bone is displaced, the lower leg may be shorter and turned outwards.
The patient’s history can vary depending on how the injury occurred. Here are some key points that medical personnel need to know during the examination:
- What happened during a low-energy injury, such as a fall? Understanding the events that led up to the fall can help rule out if the patient passed out before the fall.
- In cases of high-energy trauma – like a car accident – it’s important to first check for other urgent, non-orthopedic injuries following the Adult Trauma Life Support (ATLS) protocol. Also consider other injuries on the same side of the body, such as fractures to the thigh bone or knee injuries. For injuries from high falls, the ankle should also be checked.
- Does the patient have a significant medical history? Information about their regular function and activity level, whether they used walking aids before the injury, whether they take blood thinners, or have a history of cancer, blood clots in the lungs, or deep vein thrombosis can also be critical.
Testing for Femoral Neck Fractures
The doctor should perform a thorough nerve and blood vessel examination of the injured limb. If needed, they should order the following imaging tests:
* X-rays: these will provide images from the front to the back (anterior-posterior or AP) of your pelvis, hip, femur (thigh bone), and knee from different angles.
* CT scan: this helps to better understand the pattern of the fracture or to show a fracture line that isn’t clear. It is a part of the trauma assessment and can also look at your femoral neck (part of your hip bone).
* MRI: this isn’t generally used right after the injury, but doctors may use it to check for stress fractures in the femoral neck.
Your medical examination should also include basic blood tests (such as a complete blood count and basal metabolic panel) as well as a chest X-ray and heart rhythm test (EKG). If you’re older and have known or suspected heart disease, a heart specialist might need to check you before surgery. This pre-surgery medical check is especially important if you’re elderly.
There are many ways to classify femoral neck fractures. The most common methods are the Garden and Pauwel classifications.
In the Garden Classification:
* Type I: The fracture is incomplete – there’s no displacement.
* Type II: The fracture is complete – but still not displaced.
* Type III: The fracture is complete – and partially displaced.
* Type IV: The fracture is complete – and fully displaced.
Most often, this system is used to describe the type of fracture. For treatment, it is usually simplified into whether the fracture is displaced (Type 3 and Type 4) or not (Type 1 and Type 2).
The Pauwel Classification breaks down the fracture by the angle of the fracture line compared to the horizontal. The higher the angle, the more vertical the fracture, so these fractures are less stable and have more sideways (shear) force. These fractures are more likely to die (osteonecrosis) after surgery:
* Type I: less than 30 degrees
* Type II: 30 to 50 degrees
* Type III: greater than 50 degrees
Treatment Options for Femoral Neck Fractures
Non-operative treatment, which doesn’t involve surgery, is rarely used for these types of fractures. It’s only considered for those who can’t move around, patients who need comfort care, or people who are extremely high-risk.
On the other hand, operative treatment, which involves surgery, is usually necessary for young patients with femoral neck fractures. These fractures often need to be treated urgently with a surgical procedure called open reduction internal fixation. This type of treatment is particularly necessary for vertically oriented fractures, which are more common in younger patients or those who have suffered high-energy trauma. A device called a sliding hip screw provides more stability for these fracture types. If the fractures are displaced in younger patients, the aim is to surgically correct the fracture as quickly as possible.
If the fracture doesn’t shift in position, treatment typically involves inserting screws through the skin, into the bone, or using a sliding hip screw. However, using a sliding hip screw may result in a higher chance of reduced blood supply to the bone (9%) as compared to cannulated screws (4%).
In elderly patients with shifted fractures in the femoral neck, the treatment depends on their activity level and age. Those who are less active may undergo a procedure called a hemiarthroplasty. More active individuals often receive a total hip replacement. A total hip replacement can withstand more stress, but there is a higher risk of the hip joint slipping out of place compared to a hemiarthroplasty.
In summary, the main treatments are:
For young patients (under 60), the primary treatment is open-reduction internal fixation.
For elderly patients, if the fracture hasn’t moved, they will likely receive percutaneous cannulated screws or a sliding hip screw. If the fracture has shifted, less active patients may receive a hemiarthroplasty, while active patients may receive a total hip arthroplasty.
What else can Femoral Neck Fractures be?
A hip dislocation happens when the head of the thigh bone slips out of its socket in the hip bone. An intertrochanteric fracture, on the other hand, is when the break occurs a bit lower and is located between the two bumps at the top of your thigh bone. A subtrochanteric fracture describes a breakage that’s within approximately 2 inches below the small bump at the top of your thigh bone.
A femur fracture refers to a break within the main long portion of your thigh bone. Lastly, osteoarthritis is a condition that causes long-term joint pain and is usually experienced as groin pain. Most of the time, it gets worse with activity or climbing stairs.
What to expect with Femoral Neck Fractures
After a fracture of the femoral neck, or the area just below the ball of the hip joint, there’s a 6% mortality rate while the patient is still in the hospital. If we look at mortality rates one year after the injury, they range from 20-30%, with the most dangerous period being the first six months after the fracture.
When it comes to hip fractures in general, a little more than half of the patients, around 51%, will regain their ability to walk without assistance. However, 22% will continue to have difficulties with mobility.
Possible Complications When Diagnosed with Femoral Neck Fractures
There are several risks associated with specific medical conditions and procedures:
- Avascular necrosis, or bone death due to lack of blood supply, is more likely if there was a lot of initial movement of the bone and if the bone wasn’t properly re-aligned.
- Nonunion, which is when a broken bone doesn’t heal properly.
- Dislocation, or when a bone slips out of place, is more likely after having total hip replacement surgery.
Recovery from Femoral Neck Fractures
Patients who have had a total hip replacement or hemiarthroplasty should put weight on it as much as they can tolerate after the surgery. They have to follow certain hip safety measures depending on the surgical method used. To prevent blood clots, protection measures should start during the surrounding surgery period and continue for 4 to 6 weeks after the operation. Physical therapy should start right after the surgery.
Preventing Femoral Neck Fractures
Before the operation, it’s crucial to inform patients about the potential restrictions on their hip movements that may arise from the artificial joint. It’s equally important to guide them on how to go about their daily activities effectively. For instance, patients need to learn the right way to sit on the toilet, climb stairs, and how to properly sit down and stand up from a sitting position after the surgery.
