A hip fracture is a break in the upper quarter of the femur (thigh) bone. The extent of the break depends on the forces that are involved. The type of surgery used to treat a hip fracture is primarily based on the bones and soft tissues affected or on the level of the fracture.
The “hip” is a ball-and-socket joint. It allows the upper leg to bend and rotate at the pelvis. An injury to the socket, or acetabulum, itself is not considered a “hip fracture.” Management of fractures to the socket is a completely different consideration.
Hip fractures most commonly occur from a fall or from a direct blow to the side of the hip. Some medical conditions such as osteoporosis, cancer, or stress injuries can weaken the bone and make the hip more susceptible to breaking. In severe cases, it is possible for the hip to break with the patient merely standing on the leg and twisting.
The patient with a hip fracture will have pain over the outer upper thigh or in the groin. There will be significant discomfort with any attempt to flex or rotate the hip.
If the bone has been weakened by disease (such as a stress injury or cancer), the patient may notice aching in the groin or thigh area for a period of time before the break. If the bone is completely broken, the leg may appear to be shorter than the noninjured leg. The patient will often hold the injured leg in a still position with the foot and knee turned outward (external rotation).
The diagnosis of a hip fracture is generally made by an X-ray of the hip and femur.
In some cases, if the patient falls and complains of hip pain, an incomplete fracture may not be seen on a regular X-ray. In that case, magnetic resonance imaging (MRI) may be recommended. The MRI scan will usually show a hidden fracture.
If the patient is unable to have an MRI scan because of an associated medical condition, computed tomography (CT) may be obtained instead. Computed tomography, however, is not as sensitive as MRI for seeing hidden hip fractures.
Types of Fractures
In general, there are three different types of hip fractures. The type of fracture depends on what area of the upper femur is involved.
These fractures occur at the level of the neck and the head of the femur, and are generally within the capsule. The capsule is the soft-tissue envelope that contains the lubricating and nourishing fluid of the hip joint itself.
This fracture occurs between the neck of the femur and a lower bony prominence called the lesser trochanter. The lesser trochanter is an attachment point for one of the major muscles of the hip. Intertrochanteric fractures generally cross in the area between the lesser trochanter and the greater trochanter. The greater trochanter is the bump you can feel under the skin on the outside of the hip. It acts as another muscle attachment point.
This fracture occurs below the lesser trochanter, in a region that is between the lesser trochanter and an area approximately 2 1/2 inches below .
In more complicated cases, the amount of breakage of the bone can involve more than one of these zones. This is taken into consideration when surgical repair is considered.
Once the diagnosis of the hip fracture has been made, the patient’s overall health and medical condition will be evaluated. In very rare cases, the patient may be so ill that surgery would not be recommended. In these cases, the patient’s overall comfort and level of pain must be weighed against the risks of anesthesia and surgery.
Most surgeons agree that patients do better if they are operated on fairly quickly. It is, however, important to insure patients’ safety and maximize their overall medical health before surgery. This may mean taking time to do cardiac and other diagnostic studies.
Patients who might be considered for nonsurgical treatment include those who are too ill to undergo any form of anesthesia and people who were unable to walk before their injury and may have been confined to a bed or a wheelchair.
Certain types of fractures may be considered stable enough to be managed with nonsurgical treatment. Because there is some risk that these “stable” fractures may instead prove unstable and displace (change position), the doctor will need to follow with periodic X-rays of the area. If patients are confined to bed rest as part of the management for these fractures, they will need to be closely monitored for complications that can occur from prolonged immobilization. These include infections, bed sores, pneumonia, the formation of blood clots, and nutritional wasting.
Anesthesia for surgery could be either general anesthesia with a breathing tube or spinal anesthesia. In very rare circumstances, where only a few screws are planned for fixation, local anesthesia with heavy sedation can be considered. All patients will receive antibiotics during surgery and for the 24-hours afterward.
Appropriate blood tests, chest X-rays, electrocardiograms, and urine samples will be obtained before surgery. Many elderly patients may have undiagnosed urinary tract infections that could lead to an infection of the hip after surgery.
The surgeon’s decision as to how to best fix a fracture will be based on the area of the hip that is broken and the surgeon’s familiarity with the different systems that are available to manage these injuries.
If the head of the femur (“ball”) alone is broken, management will be aimed at fixing the cartilage on the ball that has been injured or displaced. Frequently with these injuries, the socket, or acetabulum, may also be broken. The surgeon will need to take this into consideration as well.
These injuries may be approached either from either the front or back of the hip. In some cases, both approaches are required in order to clearly see and fix the injured bone.
For true intracapsular hip fractures, the surgeon may decide either to fix the fracture with individual screws (percutaneous pinning) or a single larger screw that slides within the barrel of a plate. This compression hip screw will allow the fracture to become more stable by having the broken area impact on itself. Occasionally, a secondary screw may be added for stability.
If the intracapsular hip fracture is displaced in a younger patient, a surgical attempt will be made to reduce, or realign, the fracture through a larger incision. The fracture will be held together with either individual screws or with the larger compression hip screw.
In these cases, the blood supply to the ball, or head of the femur, may have been damaged at the time of injury (avascular necrosis).
Even though the fracture is realigned and fixed into place, the cartilage and underlying supporting bone may not receive adequate blood.
Over a period of time, this may cause the femoral head to flatten out. When this occurs, the joint surface becomes irregular. Ultimately, the hip joint may develop a painful arthritis, despite the surgical repair.
In the older patient, the chance that the head of the femur is damaged in this way is higher. It is generally felt that for these displaced fractures, patients will do better if some of the components of the hip are replaced. In some cases, this can mean a replacement of the ball, or head of the femur (hemiarthroplasty). In other cases, this can mean the replacement of both the ball and socket, or head of the femur and acetabulum (total hip replacement).
Repair of an intertrochanteric fracture with an intramedullary nail. The nail is in the hollow cavity of the femur (thighbone) rather than on the side of it (as with a plate).
Most intertrochanteric fractures are managed with either a compression hip screw or an intramedullary nail, which also allows for impaction at the fracture site.
The compression hip screw is fixed to the outer side of the bone with bone screws and has a large secondary screw (lag screw) that is placed through the plate into the neck and head of the hip (see compression hip screw figure above). The design of the device allows for impaction and compression at the fracture site. This may increase the stability of the area and promote healing.
The intramedullary nail is placed directly into the marrow canal of the bone through an opening made at the top of the greater trochanter. A lag screw is then placed through the nail and up into the neck and head of the hip. As with the compression hip screw, sliding of the lag screw and impaction of the fracture take place.
There are no definitive studies to show that one device is superior to another. The decision as to which to use is based on the surgeon’s preference and experience.
At the subtrochanteric level, most fractures are managed with a long intramedullary nail together with a large lag screw or they are managed with screws that capture the neck and head of the femur or the area immediately underneath it, if it has remained intact.
In order to keep the bones from rotating around the nail or from shortening (“telescoping”) on the nail, additional screws may be placed at the lower end of the nail in the area of the knee. These are called interlocking screws.
In certain cases, the surgeon may choose to use a plate rather than a nail. The plate will have screws that go into the bone from the lateral, or outer, side of the femur. A single large screw goes into the neck and the head of the femur and appears similar to the compression hip screw, but at a different angle. Secondary screws are then placed through the plate into the bone to hold the fracture in place.