What is Subtrochanteric Femur Fractures?
Subtrochanteric femur fractures, or breaks in the upper part of the thigh bone, are tricky to manage. This is due to strong reshaping forces at the break site, a delicate blood supply, and the huge weight-bearing forces placed on the area around the hip joint. Achieving a good realignment and securing the fracture firmly is crucial in treating these breaks to ensure the best results for the patient.
What Causes Subtrochanteric Femur Fractures?
Subtrochanteric fractures tend to occur in two distinct age groups: younger individuals and the elderly. Young people usually experience this type of fracture due to intense events like car accidents. On the other hand, elderly individuals often have these fractures after less severe incidents like falling from standing height.
Moreover, elderly patients taking a type of drug called bisphosphonate are at a higher risk of getting a unique subtrochanteric fracture. This is because these medications can weaken the outer layer of the bone, which could lead to an atypical fracture.
Risk Factors and Frequency for Subtrochanteric Femur Fractures
Subtrochanteric fractures, which make up about 7% to 34% of all femur fractures, affect males and females equally. Research indicates that 7% of patients with unusual subtrochanteric femur fractures had been treated with a medication called alendronate. Unfortunately, for elderly patients who suffer from subtrochanteric femur fractures, there’s a 25% chance of passing away within one year.
Signs and Symptoms of Subtrochanteric Femur Fractures
For elderly patients who’ve suffered a fracture due to a low-energy impact, it’s essential to understand what caused the fracture. This usually requires a detailed look at their medical history. For example, in older individuals, fractures often occur because their bones are fragile. However, if they’ve been taking bone-strengthening medications called bisphosphonates for a long time, they could experience an unusual type of fracture marked by thickening of the bone at the break. In such cases, the patient may also recall having thigh pain before the fracture occurred.
The upper part of the broken bone, which often bends inwards, could potentially damage the skin from the inside. That’s why it’s crucial to check if the fracture is open. Additionally, a thorough examination of nerves and blood vessels is needed, especially to understand if the blood supply is intact.
Testing for Subtrochanteric Femur Fractures
Your doctor will use different types of X-rays to look at the whole thigh bone, as well as the hip and knee joints. These images will help in identifying an associated injury in the thigh bone or near the knee. If the fracture extends into the part of the hip bone where the thigh bone fits in (the intertrochanteric region), it is important to check how the site where a possible surgical rod could be placed for treatment is. Techniques like a specific type of X-ray (traction view) or a CT scan may be used to better understand the injury. Additionally, another technique – an anteroposterior (AP) traction view, can help to decide the best approach for setting the bone back in place, whether that can be done without surgery or if surgical methods are required.
Doctors classify these fractures according to two common systems:
The AO/OTA system describes three types of these fractures:
- Type 32-A3.1: A simple fracture that is transverse (horizontal) and located below the joint where the hip and the thigh bone meet.
- Type 32-B3.1: A slightly more complicated fracture that has broken into several pieces and is located below the hip joint.
- Type 32-C1.1: A complex, spiral fracture below the hip joint.
The Russel-Taylor system also describes two types:
- Type I: The fracture does not extend into the small depression where the thigh bone fits into the hip bone (the piriformis fossa).
- Type II: The fracture extends into the large bony knob at the base of the thigh bone (the greater trochanter) and affects the piriformis fossa.
Treatment Options for Subtrochanteric Femur Fractures
Open fractures need to be treated quickly with suitable antibiotics. As soon as the patient arrives, a quick cleanses and removal of damaged tissue (irrigation and debridement) should be performed, and ideally, a more thorough cleaning in an operation room should done within two hours, if the patient’s condition is stable.
End-of-bed skeletal traction, a way to align and stabilize a fracture, may be considered on an individual basis. It’s usually not needed in older patients who have low-energy fractures. However, for younger patients, because their strong muscles tend to cause bone shortening and can lead to skin threats, traction can be beneficial. Assessing the knee joint using imaging can guide whether a traction pin placed in the lower thighbone or upper shinbone is required. A standard traction weight of 12 pounds (5 kg), or adjusted according to a patient’s body weight, is typically used. Weights greater than 20 pounds (9 kg) are usually avoided.
Cephalomedullary nailing, inserting a rod into the length of the bone to stabilize subtrochanteric femur fractures, is a common treatment due to its many benefits, such as less blood loss, shorter operation time, stronger mechanical support, fewer complications and faster recovery. It is crucial to assess that the starting point for nailing is intact. Depending on various factors, the patient may be positioned on their side or on their back during the procedure.
In this context, there’s not much difference between trochanteric or piriformis fossa nails. But using the piriformis fossa for start site is known to align better with the inner cavity of the bone, which might prevent unwanted bone alignment that could arise from trochanteric nails designs.
Before placing the nail, the fracture needs to be put back into place, often requiring special techniques. In order to balance between promoting bone healing, preserving blood flow to the upper thighs and achieving correct bone positioning, a variety of aids such as clamps and pins can be used, though they need careful handling to avoid disturbing the healing process. What a patient can do postoperatively, such as weight-bearing, should be handled on a case-by-case basis, often depending on how well the fracture has been fixed.
While cephalomedullary nailing is typically the preferred method, submuscular plating – attaching a metal device to the bone surface to stabilize the fracture – might be necessary when nailing is not suitable. This could be due to the fracture affecting other regions making it unsafe for nailing. In such cases, a side approach is used – the thigh bone is exposed, the fracture directly reduced, and a plate placed outside it. There’re various designs available for plates. Following this procedure, patients are generally advised against bearing weight.
What else can Subtrochanteric Femur Fractures be?
- Broken Hip
- Treatment of Broken Knee
- Broken Pelvis
- Treatment of Blood Vessel Injuries in the Extremities (Arms and Legs)
Possible Complications When Diagnosed with Subtrochanteric Femur Fractures
The most frequent issue after a fracture is fixed is that the bone heals incorrectly, creating a deformed site. This could mean either the bone doesn’t fully unite or doesn’t unite in a correct manner (a condition known as “nonunion” or “malunion”). With careful intervention initially – where the bone is accurately set and firmly secured – this problem can be reduced. However, like in all cases where nonunion can occur, professionals consider factors such as nutrition deficiencies and infections that could impede bone healing. After these factors have been excluded, the next step can be a repair surgery with an emphasis on fixing the deformity.
Recovery from Subtrochanteric Femur Fractures
Patients who have had a procedure known as cephalomedullary nailing, which helps to stabilize a fractured bone, can usually bear weight on their affected limb after the operation. However, this heavily depends on how well the fixation worked and other injuries that may be present. Another consideration is the state of the medial cortex, the inner layer of the bone, at the spot where the fracture occurred. If the fracture site is extensively damaged, these patients might need a period of immobilization post-surgery, even with cephalomedullary nailing, to avoid further complications.
On the other hand, for patients who have undergone a procedure known as submuscular plating, they cannot bear weight after surgery. They usually need to get repeat imaging around 6 weeks after the operation to check the recovery progress. If the fractures are seen to be healing correctly and are well-aligned, patients can start to bear their weight at this point. However, patients who have health problems like poor nutrition, diabetes, or other severe diseases may need additional periods of being non-weight-bearing, possibly up to twelve weeks.
