FAQ Category: Hip

Gladly! Those in favor of the minimally invasive total hip replacement (THR) say there’s less soft tissue trauma. The large muscles around the hip aren’t cut and moved aside to get to the joint.

A smaller incision also means less blood loss, less pain afterwards, and a much nicer looking scar. With fewer problems patients can go home sooner. This saves money in direct and indirect costs.

On the other hand the surgeon isn’t able to look right at the hip. It’s more difficult to make sure the implant is in its proper place. With a smaller incision it’s easier to cut a nerve or blood vessel by mistake.

Surgeons are still tracking and reporting other complications. Reports of hip dislocation and heterotopic ossification (bone growth in the muscle) are starting to trickle in.

Good question. At least one study shows that motivated patients can have a rapid recovery after total hip replacement. That IS a matter of attitude. But the same study showed that younger patients were more motivated than older patients.

The same study pointed out that recovery may be faster and easier for patients of all ages if pain is managed after the operation. Some new ideas are being put forth to help reduce tissue trauma through pain management techniques.

For example, several different ways are used to help control pain. First a local numbing agent can be injected into the operative site and around the scar. Pain medications can be used after that to help the patient get up and moving.

The goal is to have no pain, walking without a limp at the end of six weeks. The patient can be walking one to two miles without support by the end of the three months.

Again, younger patients tend to meet these goals more often than older patients. A good attitude goes a long way in rehab at any age.

As you’ve pointed out osteopetrosis is a rare condition. Not much is known about the treatment of osteoarthritis in older adults with this problem. In fact there have only been about a dozen cases reported.

Doctors from the Mayo Clinic recently presented the results of five cases of osteopetrosis and joint replacement. They also reviewed the results of seven other cases previously reported.

The most recent cases all had a good result. Three were hip replacements and two were knee replacements. There were no major problems after the operations. Patients were followed for up to 20 years.

The surgeons point out that the operation takes longer in patients with osteopetrosis. The bone is dense and must be cut with special instruments. Often the bone marrow canal is missing. This is where the stem of the implant goes. The surgeon must cut a canal in the bone for the implant.

All in all these cases show that patients with osteopetrosis can have a successful joint replacement. If you are thinking about having this done, you may want to consider going to the Mayo Clinic where the surgeons have experience with this special problem.

You’re right about the rising number of hip dislocations after joint replacement. Doctors aren’t sure exactly why this is happening. There are some possible reasons.

First, with new and better equipment and new joint implant designs, more patients qualify for the surgery. This means that patients who were too great a risk 10 years ago can now have the surgery. A greater number of dislocations still occur in this group.

Second, patients no longer stay in the hospital 10 or more days after the operation. The average stay after a total hip replacement is now less than 5 days. This increases the chances of problems occurring.

Third, the implants come in a wide range of sizes and shapes. The new designs may limit motion, eventually leading to dislocation. Placing the implant in the best position is also important. Any imbalance in positioning of the new joint can cause problems.

Hip dislocation after joint replacement is a common problem. Unfortunately, doctors can’t predict who will dislocate.

There are some known risk factors for dislocation. These include change in muscle tone (increased or decreased) and absent or extremely weak hip abductor muscles. The hip abductors allow leg motion away from the midline of the body.

Increased muscle tone occurs with neurologic disorders such as cerebral palsy or multiple sclerosis. A stroke can cause increased or decreased muscle tone. Most of these patients are not good candidates for a hip joint replacement.

Loosening and dislocation of the implant are the two most common problems faced by patients after a total hip joint replacement. The rate of dislocation varies from study to study. One study reports 0.6 percent (fewer than one patient every 100).

Other studies report up to seven percent. A very large study placed this closer to 2 percent. The wide ranges in figures may be explained by who did the surgery. Doctors in large centers or hospitals who do more hip joint replacements have lower rates of dislocation.

Most studies report numbers from these large reviews. However, most hip replacements are done by surgeons who treat fewer patients.

You may want to consider an exercise program in the pool. This is an excellent way to build up strength and endurance without the effects of gravity. The warm water also relaxes the muscles and reduces joint pain and stiffness.

You can transfer those skills on land by slowly increasing the distance walked. Many people use some support such as a cane during long walks. This enables them to increase their distance safely.

Scientists are working on this very problem. They’ve found graft material can be strengthened by washing it. The pieces of bone are put through a multi-level sieve (strainer). Fat, debris, and other non-bone particles are rinsed out. After washing, the pieces of bone fit together more closely and can accept more pressure.

Researchers in Scotland have discovered that different particle sizes and shapes also make bone graft stronger. The uneven edges allow for tighter interlocking pieces. The graft is more compacted when a broad range of particle sizes are used.

A “stovepipe canal” refers to the size and shape of the hollow part of the long upper leg bone called the femur. When a hip is replaced, the head of the femur is cut off and a new one is put in its place. The new head is attached to a long stem that slides down into the femoral canal.

The chances of the implant coming loose are greater if the canal is large and round or “stovepipe” in shape. Any sign of loosening must be reported right away. The doctor will also take X-rays and watch for any signs of problems.

Studies of hip replacement for developmental dysplasia show a wide range of results. A recent report from Japan shows the results after hip replacement for this problem. Some patients were followed for 26 years. Besides the new joint, each patient had a large bone graft used to form a deeper hip socket.

They found that problems are more likely to occur in patients under age 50 with this operation. The authors suggest that other operations can be tried first before removing the joint and replacing it. Patients must be advised about the right level of activities. This will help preserve the hip before surgery.

What hasn’t changed is a better question?! Let’s start with the joint implant itself. The implants come in many different sizes. Each patient’s hip is measured and evaluated carefully before the doctor selects the right replacement joint.

The material has changed from stainless steel to titanium or polyethylene (a type of plastic). The new implants are stronger, harder, and less likely to break or come loose.

New tools have changed the way doctors remove the old joint and replace it with the implant. In some cases, the doctor can use an arthroscope to see inside the joint. This tool has a tiny TV camera on the end and allows the doctor to pass small surgical instruments through the opening. Only a small incision is made with this method compared to the large cut used years ago.

Length-of-stay in the hospital and rehab programs have changed, too. The patient gets home and follows a home program sooner than ever before.

There’s a known relation between hip dislocation and squatting after hip joint replacement. Studies from Korea and other Asian countries report a high rate of revision surgery for this problem.

Doctors in these countries are studying the problem. It may be that using a smaller implant will help. The head of the thighbone (femur) is shaped like a round ball. It sits up inside the hip socket. Using an implant with a smaller head may help it stay inside the socket (or cup if the socket is replaced, too).

Be sure the doctor is aware of your mother-in-law’s habits and your concerns. The type of implant used may be selected based on this information.

Right, but our ability to tell that from outside the body is limited. X-rays may show some changes that occur when the implant starts to loosen. In the early stages, the changes aren’t always large enough or clear enough to know for sure.

For the purposes of evaluating implants, the area around the joint implant is divided into zones. The socket or cup side has three zones, whereas, the femoral side has 14. A problem can occur in any one of these zones.

Sometimes, doctors must make an educated guess. In defining the problem, the doctor may say that here is definite, probable, or possible evidence of loosening. Further testing (and sometimes waiting) is often the next step.

The term osteonecrosis refers to the death of bone and bone marrow. This occurs when there’s a loss of blood flow to the area. Two other terms for this condition are: avascular necrosis and aseptic necrosis. Avascular means “without blood” and aseptic means “without infection.”

Alcohol abuse leads to a change in how fat is broken down and used. This process is called fat metabolism. Tiny pieces of fat can break off like a blood clot and block the blood vessel. This is what happens in the case of osteonecrosis from alcoholism.

Once the blood flow to the hip is cut off, bone cells start to die. The bone weakens and collapses or breaks. A fall or other injury may be the first sign there’s a problem.

There are several methods for replacing the hip joint. The doctor may open the hip from the front, side, or back. This usually requires a long incision so that the doctor can see the entire joint.

More recently, new equipment is making it possible for doctors to “see” the joint using a computer. A special navigation system uses software, imaging, and an infrared eye to track inside the hip. The doctor makes a small window opening in the tissue and uses the tracking tools to see what’s he or she is doing.

This makes for a smaller incision and may explain why you’re seeing a difference in the length of the scar.

When patients with hip joint replacements are compared, there are very different results in wear patterns of the new joint. This is true even when the same replacement parts are used from patient to patient.

In fact, one study looked at patients with both hips replaced using the same implant. The researchers compared one side to the other and found that the wear pattern was different from side to side. One of the reasons for this is third-body wear.

This is the presence of tiny particles in the joint. These pieces may be bits of bone or fragments of glue or cement used to hold the new joint in place. Even metal debris from the coating around the joint implant can cause the joint liner to be scratched and roughed up. Joint wear and tear is increased when the surfaces are roughened.

X-rays are an easy and inexpensive way to see the implanted hip joint. Sometimes, X-rays don’t turn out or the view isn’t clear. In these cases, the X-rays can be done over quickly and easily at a low cost.

MRI (magnetic resonance imaging) doesn’t show certain parts of the bone and isn’t used for this kind of purpose. Other types of imaging such as CT (computed tomography) scans give a more accurate picture. With CT, even the amount of extra cement that oozes out from around the implant can be seen and measured. Even so, CT scans aren’t usually used for these types of measurements. The cost is too much for this kind of study.

Arthritis sufferers are known to have poor sleep patterns caused by pain. Conditions such as osteoarthritis are a common source of hip pain in the older adult.

A recent study in New Zealand showed that sleep is improved after hip joint replacement. All patients had painful symptoms from arthritis that woke them up at night. Less hip pain after the operation meant better sleep. If the patients were awakened from sleep, it was for some other reason than from hip pain.

Even healthy older adults are at risk for dehydration (fluid loss). There is a decrease in thirst as we age and thus, a tendency to stop drinking liquids as much. Many Americans confuse thirst with hunger and eat instead of drinking.

Older adults who have hip joint surgery are also at increased risk of dehydration. There is blood loss with this operation. The problem gets worse if the patient has nausea and vomiting from medications. The presence of any other medical condition such as diabetes, high blood pressure, or thyroid problems adds to the mix.

Even mild to moderate dehydration can slow a patient down. Dizziness, weakness, and fatigue are common. Just getting through the daily activities or dressing, eating, and personal care can zap a patient’s strength. There may be no energy left for exercise needed after this operation.

Results from a recent study show that an eight-week program of exercises before surgery for a total hip replacement is best. Patients who exercise before the operation are less stiff and have less pain. They also have better motion and function.

Exercises will be continued after the operation. Usually, these begin again about three weeks after the procedure. The same exercise program can be used again. Patients begin with a few exercises and slowly progress. Continue the program until 12 weeks after the operation. It’s often helpful to have a physical therapist guide you in choosing the right exercises.