Stress fractures of the hip once most commonly affected military personnel who marched and ran day after day. Today, stress fractures of the hip are more common in athletes, especially distance runners.
There are two types of stress fractures. Insufficiency fractures are breaks in abnormal bone under normal force. Fatigue fractures are breaks in normal bone that has been put under extreme force. Fatigue fractures are usually caused by new, strenuous, very repetitive activities, such as marching or distance running. Most stress fractures of the hip are fatigue fractures. The stress fractures this article refers to are fatigue fractures.
This guide will help you understand
- How a stress fracture develops
- How docotrs diagnose the condition
- What treatment options are available
What is a stress fracture, and what part of the hip is involved?
The femoral neck has to withstand extreme force even during normal activities, such as standing still. The normal contraction of muscles during walking makes this stress even higher. Running triples the stress on the femoral neck.
Surgeons put fatigue fractures of the femoral neck into three categories. Compression fractures occur on the underside of the femoral neck. Tension fractures occur on the upper side of the bone and can cause more problems than fractures on the underside of the femoral neck. In displaced fractures, the bone cracks all the way through, and the two bones no longer line up correctly.
A displaced stress fracture is a very serious problem in a young adult because it may lead to damage to the blood vessels going into the upper end of the hip bone. This can cause a very serious complication known as avascular necrosis (AVN) of the hip.
Patients with fatigue stress fractures of the hip are also likely to have muscle and tendon injuries and swelling of the synovial lining (the lubricated lining) of the hip joint.
Stress fractures can also happen in the shaft of the femur bone, the greater trochanter, and the pelvis bone. The greater trochanter is a large bump below the neck of the femur. The buttock muscles that move the hip connect to this part of the femur.
Why do I have this problem?
Bones can usually adapt to repetitive stress, and any change in the function of a bone causes it to change the way it is built. This is how small bumps and ridges form on bones. The tendons pull on these areas, and the bone adapts by building up. This is normal. But extreme stress repeated too often can overwhelm the bone’s ability to adapt. This is especially true when someone suddenly begins a new, strenuous, repetitive activity such as running.
Fatigue fractures are related to both the amount of exercise and how fast people increase their exercise program. The more people run or march, the more likely they are to develop a fatigue fracture. Research suggests that most athletes who develop stress fractures have been training for at least two years, six or more times a week. A stress fracture is more likely to occur after an increase in how far, how often, and how hard a person goes.
Women are up to 10 times more likely to develop fatigue fractures than men. The reasons for this are unclear. Hormonal changes may make women athletes’ bones more likely to fracture. Eating disorders, which are more common in women athletes, may also make bones more likely to fracture.
Age also makes stress fractures of the hip more likely. This is thought to be due to declining levels of physical fitness more than age.
What does a stress fracture of the hip feel like?
How do doctors identify the condition?
Your doctor will probably suggest taking an X-ray of your hip. The X-ray may help rule out other problems, but it probably will not show the stress fracture.
Your doctor may recommend other imaging tests that are more likely to show a stress fracture. A bone scan may be suggested to look for early signs of a stress fracture. A bone scan involves injecting tracers into your blood stream. The tracers then show up on special X-rays of your hip. The tracers build up in areas of extra strain to bone tissue, such as a stress fracture.
The magnetic resonance imaging (MRI) scan is especially useful in telling fatigue fractures from other types of injuries with similar symptoms. The MRI is being used increasingly in cases where doctors suspect a stress fracture.
What can be done for the problem?
Doctors most often recommend nonsurgical treatment for compression-type fatigue fractures. You must stay off the affected leg, using crutches if necessary, and rest the hip for at least four to six weeks. Pain can be treated with hot and cold treatments and medication. With care, the fractures tend to heal by themselves.
Surgeons do not all agree on how to treat tension fractures. If the fracture is not at risk for displacing, surgeons may have patients use crutches to keep strain off the hip during standing and walking. X-rays are taken every few weeks to make sure the bone is healing. If the tension fracture is in danger of displacing, however, most surgeons will operate. This is because the complication of AVN can cause the femoral head to actually lose its blood supply and collapse. This leads very rapidly to degenerative arthritis of the hip joint. Because these effects can be so devastating, most surgeons recommend surgery if they feel that the stress fracture is in danger of displacing.
In some patients with a fracture under the femoral neck, MRIs and other imaging tests sometimes show an unstable fracture that needs to be surgically fixed.
The surgical procedure is the same whether the stress fracture is stable or there is only a slight displacement of the bones. If your surgeon recommends surgery for a stress fracture of the hip, several large metal screws will be inserted through the femoral neck to hold the fractured bones in place while the fracture heals.
To perform this procedure, a small incision is made on the side of the upper thigh. With the help of a special X-ray machine called a fluoroscope, the surgeon can insert the metal screws into the proper position while watching the X-ray image on a TV screen.
When the ends of the bones show a large displacement, surgeons aren’t in total agreement about which surgery is best. Most surgeons agree that younger, active patients benefit if surgery is done to save the femoral head. This method also uses screws to connect the two sections of bone.
To avoid problems with AVN, other surgeons feel that older, less active patients should have part or all of the hip joint replaced. If the socket of the joint is healthy, the surgeon may decide to replace only the ball portion of the joint, a procedure called hemiarthroplasty.
The procedure to replace both the ball and the socket with an artificial joint is called total hip arthroplasty.