The “hip” is a ball-and-socket joint. It allows the upper leg to bend and rotate at the pelvis. Note that an injury/fracture to the socket (acetabulum) is not classified as a hip fracture and requires different diagnostic and management considerations.
Hip fracture is very common. Falls are the commonest cause, followed by 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.
Women have two to three times as many hip fractures as men. White, post-menopausal women have a 1 in 7 chance of hip fracture during a lifetime. The rate of hip fracture increases from age 50, doubling every five to six years. Nearly one half of women who reach age 90 have suffered a hip fracture.
Pain is experienced over the outer upper thigh or in the groin. There is 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), there may be aching in the groin or thigh area for a period of time before the actual break. If the bone is completely broken, the leg may appear to be shorter than the noninjured leg. The injured leg is often held in a still position with the foot and knee turned outward (external rotation)
Diagnosis is generally made by an X-ray of the hip and femur. Hip fractures occur at the upper end of the thigh bone (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 MRI is not an option, computed tomography (CT) may be used instead, although it is not as sensitive for detecting hidden hip fractures.
Imaging is important to classify the type of fracture, which has implications for treatment. There are three different types of hip fractures, depending on what area of the upper femur is involved. Intracapsular 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. There may be associated loss of blood supply to the bone. Intertrochanteric fractures occur 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. Subtrochanteric fractures occur below the lesser trochanter.
The treatment of a fractured hip is usually surgical. In a small number, the fracture may be considered stable enough to be managed nonsurgically, with regular xrays to ensure the fracture does not become displaced.
Most surgeons agree that patients do better if they are operated on fairly quickly. It is, however, important to ensure patients’ safety and maximize their overall medical health before surgery. This may mean taking time to do cardiac and other diagnostic studies.
The three different types of fracture have different treatment options.
1. Intertrochanteric Fracture
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 nail is in the hollow cavity of the femur (thighbone) rather than on the side of it (as with a plate). 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.
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.
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. We are currently running a study to study the differences, and you may of been invited to participate prior to surgery.
2. Intracapsular fracture
For intracapsular hip fractures, the surgeon may decide either to fix or repair the fracture with plates or screws or alternatively perform a type of replacement.
If the fracture is minimally displaced, or deemed to be in an acceptable position, then the fracture may be fixed with screws that are placed through small “percutaneous” stab incisions on the side of your leg
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.
When an intracapsular fracture is fixed, 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).
Hemiarthroplasty is a type of hip replacement in which only the “ball” of the hip is replaced.
A total hip replacement replaces both the hip socket and ball.
3. Subtrochanteric Fracture
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.
Interlocking screws at the end of the nail make the fixation more secure.
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.
Medical Care in Hospital
It is not uncommon to require a blood transfusion after surgery on account of bleeding secondary to the fracture. Medication to this the blood is often prescribed for up to 6 weeks. This is to reduce the chances of developing blood clots. Elastic compression stockings or inflatable compression boots may also be used.
Patients may be encouraged to get out of bed on the day following surgery with the assistance of a physiotherapist. The amount of weight that is allowed to be placed on the injured leg will be determined by the surgeon and is generally a function of the type of fracture and repair (fixation).
The physiotherapist works to help regain strength and the ability to walk. This process may take up to three months.
Following hip fracture surgery, most patients will regain much, if not all, of the mobility and independence they had before the injury.