News Category: Hip

Cost-cutting is just part of health care these days. Insurance companies, hospitals, and doctors are all trying to move patients through the system as quickly as possible. For patients who get total hip replacement (THR) surgery, this means less time in the hospital.

These authors felt like they were seeing more hip dislocations in THR patients soon after surgery. Dislocation after THR can happen when the leg is put in certain positions or does certain movements. Patients get a lot of physical therapy and nursing attention in the hospital after THR. Much of this care involves teaching patients to avoid putting their new hip at risk of dislocating. It is possible that shorter hospital stays resulted in not enough patient education to avoid dislocation.

The study looked at 850 patients who had THR in the 1990s. All patients had THR done in the same North Carolina hospital. All patients had the same type of implant. There were 24 hip dislocations in the first three months after surgery. The rate of hip dislocations was 0.5 percent in the early part of the 1990s. At that time, the average hospital stay was about seven days. Later in the 1990s the average stay was about four days. At that time, the dislocation rate had gone up to almost four percent. This is still a fairly low rate. But the authors were concerned that the dislocation rate went up six times as hospital stays shortened.

Most of the dislocations happened about 20 days after surgery. It is impossible to say whether a longer hospital stay could have prevented these dislocations. Still, it seems clear that shorter hospital stays mean more dislocations after THR. Other studies suggest more problems after knee replacement and some spine surgeries, too. The authors say that their goal was to bring attention to this problem. They call on doctors and hospitals to focus on good patient education to help avoid dislocations after THR.

Doctors are learning that patients’ expectations before total hip replacement (THR) surgery are important. Some patients think THR will return them to their glory days of activity and improve their social lives. Chances are these patients are setting themselves up to be disappointed.

These authors studied patients’ expectations right before THR. They questioned more than 1,000 patients. They found out several interesting things:

Hybrid corn. Hybrid beef. Hybrid hips? Hybrid means a mixture or combination of two things. A total hip replacement (THR) is made up of two main parts. There’s the socket, or cup, and the femoral stem. The stem fits down into the long thighbone (femur). The stem has a round head at the top that fits up into the cup.

A hybrid THR has a cemented femoral stem and a cementless cup. A hybrid THR can be used in patients with osteoarthritis from hip dysplasia. Hip dysplasia occurs when the natural socket is shallow and flat instead of deep and round. With hip dysplasia, the head of the femur doesn’t sit securely inside the socket. There is a greater risk of hip dislocation when dysplasia is present.

THR in the dysplastic hip can be a challenge. The shape of the bone on the cup side may not give enough bone for a cup implant to fit into. Sometimes a bone graft is used to build up the bone in the socket.

How well do the hybrid THRs hold up in the dysplastic hip? That’s the focus of this Japanese study. One hundred patients with hybrid THRs were followed for an average of 10 years. The authors found that only two patients needed a second operation to revise the implant. Almost half of the hips with bone graft to build up the bone had problems with the cup side of the implant. There was movement and rotation of the cup after it was placed inside the bone. The cup didn’t come loose, so the researchers think the changes were caused by bone loss in the graft.

The doctors in this study stopped using bone graft in hips with mild dysplasia. Instead, they changed the position and location of the cup as it is placed into the bone. This method also allows doctors to help the patient make up for a difference in leg length. Since no cement is used to hold the cup in place, revision (if needed) is easier. The authors conclude that a hybrid THR for patients with osteoarthritis from developmental hip dysplasia gives good results. It’s an acceptable choice for patients with dysplasia
who are 55 years old or older.

Hip fracture? You’re not alone. Every year more than a quarter of a million people in North America have one. When this many people are affected, doctors want to know: what’s the best way to treat the problem?

For most broken hips, there are two choices: fix it or replace it. Fixing the fracture with a plate and screws or just screws is called internal fixation. This is a faster and easier way to treat a hip fracture, but there’s a risk that the fracture won’t heal. If the fracture has displaced, it usually means that the blood supply to the top of the femur has been cut off. This can result in a condition in which the top of the femur dies. It’s called avascular necrosis (AVN). When AVN happens, the patient ends up needing a joint replacement.

There are several types of hip replacements to choose from: total, partial, or a special swivel type called a bipolarimplant. The good thing about a hip replacement is that it does away with the potential for AVN due to a displaced fracture.

Doctors at McMaster University in Ontario, Canada, reviewed studies from 1969 to 2002. They found nine trials with a total of 1,162 patients to compare. All subjects either had internal fixation or joint replacement. Several measures were used to compare the two treatment methods. These included the number of deaths, pain levels, function, operating time, infection, and the need for revision.

The authors found a greater risk of death and infection with a total hip replacement in the first four months. Pain levels and function were equal between the two treatment choices. Patients who had a total hip replacement lost more blood, and the operation usually took longer than for internal fixation.

The authors of this study say that hip replacement after hip fracture means only one operation to fix the problem. The risk of complications is higher with joint replacement. On the other hand, the need for a second surgery after internal fixation can be as high as 50 percent in some patients.

Is death more likely after total hip replacement compared with internal fixation? It appears so. Researchers think a larger study with more patients will give us the final answer about the best treatment after hip fracture.

Here’s a true conversion story. Doctors at the Joint Replacement Center of Korea converted a fused hip into a moveable joint. They did this with a total hip replacement (THR). Actually, 86 patients had a fused hip joint converted to a THR.

There are varying reports on the results of THR for fused hips. Some studies show the implant lasts for years after the conversion surgery. Others report a high failure rate. Younger patients and those who have already had other surgery on that hip are more likely to fail.

THRs can be put in with or without cement. This is the first study to look at cementless THR when converting from a fused hip.

The researchers set out to answer four questions:

Doctors prefer that their patients be educated, especially when their patients are planning to have surgery. The hope is that patients will understand better what they are agreeing to. Doctors also want to ease patients’ worries and prepare them for the work of recovery.

But what is the best way to educate patients? Does it really matter? These authors report on a study done in Paris, France. Patients about to have hip replacement surgery were divided into two groups. All patients got the usual information from their doctors, along with a brochure. One group got much more intense education. Before surgery, they went to a half-day class with two doctors. The doctors gave a presentation about hip replacement surgery. The groups were very small, so it was easy for patients to talk to
the doctors and ask questions.

Before surgery, the patients all answered questions about pain and anxiety. They also answered questions one day and one week later. Results showed that people who got extra education were less anxious before surgery. They also reported less pain going into surgery. After surgery there weren’t many differences between the two groups. The main difference after surgery was that those who went to the class were able to stand up earlier after hip surgery. This could be because the class had stressed the importance of standing as soon as possible.

The authors conclude that extra education can help prepare patients for surgery. They note that further research would be needed to find out which part of the education program was most useful–attending the class, the information given during the class, or the chance to talk to doctors.

Getting a hip joint replacement? What type of implant is best: ceramic, plastic, or metal? How about half-and-half: part metal, part plastic, or ceramic on metal? There are quite a few choices, but researchers are trying to narrow down the best ones.

At the School of Mechanical Engineering in England, scientists have a simulation lab. They test joint replacements using different materials and under varying conditions. This study reports the results of testing a metal head (the round top at the upper end of the thigh bone) and a ceramic socket.

The implants were tested as if under low wear, high stress, and with different amounts of joint laxity. The simulator put the joints through a walking cycle equal to 12 months of wear.

Under low stress the metal head against the ceramic cup showed mild wear. The problem came when joint laxity(looseness) causes the head of the femur to hit the rim of the socket. This is called microseparation. It occurs just as the person puts the heel down to take a step.

The result is a tiny fracture in the ceramic where the femoral head hits the rim. Over time, a stripe of wear forms on the femoral head, with a matching wear pattern in the socket. The hip starts to squeak or click. The joint surface gets rough, and the fracture in the implant can worsen.

The authors of this study aren’t in favor of using metal on ceramic in hip joint
implants. They say studies like this are needed for all kinds of joint replacements before they are used in humans.

Have you ever really tried to fit a square peg in a round hole? It can be done if the hole is big enough. If not, you could break the peg. This is a bit like the problem doctors face when putting a straight stem into a curved bone during a total hip replacement procedure.

The thighbone (femur) is straight at first, but then curves slightly as it gets closer to the knee. Doctors use X-rays before the operation to see the size and shape of the femur. This helps them choose the right implant for each patient.

A big concern is that fractures at the tip of the implant aren’t always visible during the operation. They probably occur when the implant is put in place down the shaft of the femur. X-rays are taken in the operating room after the stem is in. Finding a fracture during the operation can prevent a second surgery later.

Doctors at the Mount Sinai Hospital in Toronto, Canada, are studying the problem of bone fractures at the tip of uncemented long-stem hip implants. From their findings, they make several suggestions. These apply to patients who have had a failed first hip replacement and are now getting a second implant:

Radiation treatment is used for more than just cancer. It also helps prevent a condition called heterotopic ossification( HO). HO is an overgrowth of bone that is not malignant. It’s also known as myositis ossificans.

Some patients receiving a total hip replacement are at risk for HO. Preventing this problem is a goal after surgery. The best way to do this is with radiation. Using the lowest dose while still preventing HO is the focus of this study.

Patients were divided into two groups. One group got 500 cGy (centigray) while the other group had 1,000 cGy. Radiation can cause hardening of the tissues. It can also keep the bone from growing around the new implant. So researchers are looking for the lowest dose that works while still preventing HO. The results of this study show that 500 cGy is effective in preventing HO without causing other problems from the use of radiation.

But does everyone having a hip replacement need radiation? No, just patients at increased risk for HO. This includes patients who’ve had HO before and patients who have other bone problems such as ankylosing spondylitis or bone spurs in the spine. Past studies suggest that the type of surgery and the way the implant is put in can make a difference, too.

Is 500 cGy the lowest dose needed to prevent HO? Researchers don’t know yet. This is the first study to try the use of 500 cGy. Bone growth around the implant wasn’t a problem with this dose. A larger study is needed to confirm these results before trying an even lower dose.

Doctor No. 1: Mrs. Jones needs a total hip replacement. I think we’ll use the posterior approach and come in from behind. There’s less blood loss, and it’s easy to get to the hip.

Doctor No. 2: That may not be such a good idea. She’s more likely to dislocate after a posterior operation. In fact, studies show the dislocation rate is two to three times higher than when the hip is put in from the front (anterior approach).

Doctor No. 1: There isn’t a lot of agreement from various studies which way is best. I don’t think a posterior approach has to mean dislocation. It depends on how we put the implant in and how well Mrs. Jones follows our instructions.

Doctor No. 2: I just read a study done by three doctors who replace the joint using a posterior operation. They repair the backside of the joint capsule after cutting into it. They also reattach the short muscles that rotate the hip. The soft-tissue repair seems to make a big difference in the number of hip dislocations.

Doctor No. 1: Really? Tell me more about the results.

Doctor No. 2: Dislocations only occurred in eight of the 945 total hip replacements put in using the posterior approach. That’s less than one percent. Other studies report a range from one to nine percent with a posterior approach and up to three percent with an anterior method. In this study, two hips dislocated because of a traumatic injury. Only two of the eight had a second operation to revise the hip.

Doctor No. 1: So with the right-sized implant put in with good alignment, we can reduce the number of dislocations when using a posterior approach?

Doctor No. 2: Yes, so long as we make repairs to the soft tissues that are cut in the process. Let’s go over our exam findings and see if she’s a good candidate otherwise for a posterior approach.

Doctor No. 1: Great idea. I’ll get her chart and meet you back here in five minutes.

Hydroxyapatite is a calcium coating on joint replacement parts. It’s used to increase the amount of bone-to-implant surface contact. Bone-to-implant contact is important. The more bone that fills in around a joint implant, the more secure the fit.

Researchers in Korea are testing the results of this coating in hip joint replacements. They studied 50 patients who had both hips replaced, one at a time. In all patients one implant had the coating, the other didn’t. Using implants with and without this special coating in the same patient makes comparisons easier. The hips are the same in terms of the patient’s gender, age, weight,health, bone quality, and activity level.

Results were measured for each patient’s pain levels, function, changes in the bone, and implant loosening. At the end of the study the authors had no preference for one implant over another. All measures used had similar or equal results.

The authors conclude that hydroxyapatite coating on joint replacements doesn’t seem to make any difference. Results are no better and no worse. They think the reasons for this are better surgical technique and improved implant design. Newer implants get a close fit inside the bone, so the special coating isn’t necessary for a better fit.

Once upon a time, patients did most of their recovery in the hospital. Today the trend is to send patients home as early as possible. This is cheaper for insurance companies. It can also be better for patients. Hip fractures usually occur in older adults. These patients usually stay in the hospital while they heal. This study from Australia compared the traditional approach to a home rehabilitation program.

All patients were over 65 and living on their own and in fairly good health before hip fracture. All of them spent two days in the hospital. Then one group stayed in the hospital for conventional rehab. The other group was sent home. Nurses, therapists, and other specialists and helpers were sent to their homes as needed. Both groups did hip exercises as part of rehab.

Researchers looked at the two groups over one year. Patients answered questions about their activities and quality of life. Researchers also tested patients’ ability to move. Importantly, caregivers also answered questions about the burden of helping the patients.

At one year, there was no real difference between the two patient groups. Yet there was a difference in the caregiver groups. The caregivers for patients getting home therapy reported a bigger decrease in their burden over the year.

The authors note that doctors should choose patients for home therapy very carefully. Patients and caregivers need to understand what they’re getting into. The patient must have a home that will work for a person who can’t get around well. And there needs to be good support in the patient’s community. But overall, this study suggests that home therapy can be effective for older patients with hip fractures.

When it comes to cost, a total hip replacement is one thing. But revising a failed implant is much different. No one knows better than the Hospital for Special Surgery in New York City, where this study was done on the high cost of this type of operation.

Revision surgery for a failed total hip replacement is complex and time consuming. It requires hospital space, staff, and a long hospital stay. The operation lasts longer than the original hip replacement. Bone loss is common. Often patients also need a bone graft during the procedure.

The expense of total hip revision remains high even after efforts on the part of hospitals to reduce costs. The authors of this study report the actual costs (not what was charged) for patients having a total hip replacement revision. Costs were added up in categories. Categories included operating room time, supplies, hip implant, and recovery room. Other cost categories are pharmacy, room and board, and rehab. The researchers looked for costs
above and below the average.

The authors report that costs increased with the patient’s age. This is linked to the fact there are more complications in older patients. The cost was less if only part of the implant is revised or replaced. The cost was more if bone graft was used.

The authors also reported how much hospitals received from insurance companies. They found a loss for every patient over the age of 65. Patients over 65 had higher costs and lower reimbursement. And almost 60 percent of the patients in this study were older than 65.

The hospital’s cost of a total hip revision is high compared to how much the hospital receives in payment. Revisions take a lot of hospital resources and often result in a loss of money for the hospital. The authors hope tracking costs and payments for operations will help hospitals get better reimbursement in the future.

Imagine not being able to drive to work, to run errands, to concerts or movies, or to visit friends and family. At first this might seem like a nice break from your hectic pace of life. After all, riding the bus can be fun, and you can catch up on your reading.

But what if you live in a place where there’s no bus service? Now imagine you’ve had a total hip replacement (THR) and can’t walk to the bus stop or step up on the bus. Suddenly the value of driving increases more than ever. How soon can you get back behind the wheel after a THR?

Many doctors advise waiting four to six weeks. This gives the soft tissues a chance to heal. However, no one knows if this is a safe recommendation. To help with this decision-making process, a group of physical therapists studied 90 patients after THR. They measured the patients’ reaction time. Reaction time is how long it takes for the patient to react to a red traffic light and brake the car.

A driving simulator system with an automatic timer was used. Only English-speaking drivers with a current license were included in the study. The cars had to have an automatic transmission. Patients used the right foot for the gas and brake. Patients ranged in age from 34 to 85 years. Patients’ reaction times after THR were compared to normal reaction times published by the American Automobile Association (AAA).

The authors reported a general pattern of worse reaction times for everyone one week after the operation. One year after the operation women had better reaction times than men. This was true even though men had faster times before the THR. Based on the findings of this study, the following guidelines are proposed for driving after a hip replacement:

Elvis Presley was often accused of having loose hips. That’s okay for someone in the world of rock and roll. But adults who have a total hip replacement (THR) need a stable implant. There are many reasons why hip implants come loose. The authors of this study think one cause may be the immune system. Some patients may react to the materials in the implant, which leads to loose hip joints.

The authors studied 90 replacement hips and divided them into two groups. The first group had loosening before 15 years. The second group had loosening after 15 years. All patients had a blood test and X-rays.

Many different human leukocyte antigens (HLAs) were measured in these two groups. HLAs are part of the immune system. They are numbered to keep track of them. Each person has HLAs as unique as fingerprints. They tell the immune system, “It’s me!” When the immune system sees the HLA, it recognizes it as part of its body and leaves it alone. HLAs are inherited. Some can increase a person’s chances of getting certain diseases.

In this study, patients who tested positive for HLA-A31(19) had three times as many loose hips as those who tested negative. The number of hips with a positive test was greatest in the group with loosening before 15 years. There were some patients with a lot of wear in the socket but no loosening. They didn’t have the A31(19) antigen.

The authors of this study conclude that a patient’s immune response to implant particles, together with HLAs, may be a risk for loosening is certain implants.

Technology continues to improve and expand what doctors can do. A new laser-scanning microscope can tell if a patient’s hip replacement is infected. The time to get results is only about 30 minutes.

Hip infection is the second most likely cause of implant failure. Hospitals can’t afford to go without this new tool. It costs $50,000 to replace an infected artificial hip joint. The cost of the laser-scanning microscope is around $350,000. That seems high, but each year in the United States thousands of aging adults need joint replacements. The hospital would get back what it spent if only seven patients are saved from a failed revision surgery.

There are several ways to test for infection. One is to pass a cotton swab across the infected area. The second is to take samples of tissue from around the implant. In both methods, samples are then tested for bacteria and other organisms. This is called a tissue culture. A more thorough search for infective agents involves culturing the implant itself. The surface of the cup, the cement surfaces, and the stem are scraped. The scrapings are then cultured.

The hospital cultures must be held in the lab for up to seven days to detect many of the infectious agents. Even then not all the bacteria actually present shows up. In comparison, the laser-scanning microscope scans the implant and gives results within 30 minutes. It’s fast and doesn’t allow the samples to dry out. It also shows when there are multiple strains or subtypes of bacteria present.

In this study, researchers compared the results of tissue cultures from tissue samples and those taken from the actual implant. They used the standard hospital procedure and compared it to the newest method using the laser-scanning microscope. The authors point out that early detection of all the possible infectious agents is a big step toward reducing failure of hip revisions. It’s likely the new implant will get infected too if all the bugs aren’t gone before the new implant is put in.

On the basis of this study, it is suggested that tissue cultured from failed hip implants include scrapings from the original joint replacement. A laser scanning microscope will show the results quickly and accurately.

Do some total hip replacements last longer because of the way they are sterilized before packaging? This is the question studied by researchers at the Anderson Orthopaedic Research Institute in Virginia.

The authors looked at the rate of wear for two different hip implants. They followed patients for up to 16 years. Sterilization is used to kill any bacteria or viruses in the materials. One group of implants was sterilized using gamma rays (irradiation). The second group was sterilized using ethylene oxide, a chemical that treats the surface of the implant.

Before starting the study, the scientists thought there could be three possible results:

The pain of osteoarthritis (OA) can be crippling. The usual treatments are anti-inflammatory drugs and physical therapy. Sometimes steroid injections can ease pain, at least for awhile. But, in general, none of these treatments works very well for very long. The idea is to manage the pain of OA as long as possible. Doctors are always looking for new treatments that can help patients better manage the pain of OA. Joint replacement is put off until the pain is severe and activities are very limited.

Hylan injections are a newer treatment for OA. Hylan is a synthetic type of hyaluronic acid (HA). HA is naturally found in the fluid inside joints. No one understands exactly how HA works, but it seems to lubricate the joint, protect the cartilage, and maybe even slow the process of OA. Hylan injections have shown promise in easing the pain of knee OA. It has not been tested much in other joints. These authors tested hylan injections in hip joints with OA.

The injections were tested in 25 hips. None of the patients was getting good relief with standard treatments. Most of the patients had mild to moderate OA, and a few had severe OA. They all got a joint-rinse with saline (called lavage) in the fist week. They got one hylan injection a week for the next three weeks. All the patients also did a four- to six-week program of hip exercises.

One year later, most patients still had less pain. The authors considered success to be at least 50 percent less pain and a patient rating of the treatment as good or excellent. For patients with mild or moderate OA, the success rate was just over 90 percent. For patients with severe OA, the success rate was 50 percent.

This study suggests that hylan, together with an exercise program, can ease the pain of mild to moderate hip OA. More studies are needed to support this finding. But patients with hip OA–and their doctors–will be glad to have another possible tool to use against pain.

Wilhelm Conrad Roentgen discovered the use of X-rays in 1895. He was working as a professor of physics in Germany. He called the unknown radiation “X-rays,” since “X” frequently stands for an unknown amount in math. His discovery changed the world of medicine. For the first time doctors could “see” inside their patients.

Today X-rays are still useful, but they have their limits. One of these limits is seeing areas of osteolysis in the pelvis after total hip replacement. Osteolysis is the breakdown of bone. It’s a problem that can occur when hip implants are put in without cement. Areas around the hip implant can be hidden on X-ray. The shadow of the implant itself causes this problem. Doctors need to know how many and how large the areas of bone breakdown are when planning surgery to revise the joint replacement.

Researchers at the Anderson Orthopaedic Research Institute in Virginia measured the accuracy of X-rays in finding osteolysis. They used cadavers (human bodies saved for research). They put cementless hip implants in eight cadaver hips. Hip X-rays were taken. The implants were taken out and holes were made in the pelvic area of each hip. The size and shape of each hole was measured. The implants were put back in and more X-rays were taken.

The holes were redrilled two more times. The size of the holes was measured and X-rays taken each time. The scientists found that X-rays showed osteolysis just over 40 percent of the time. This means more than half the time the patient has unseen osteolysis. The authors report that larger lesions are more likely to be seen. Even so, the extent of osteolysis was underestimated using X-rays. When an experienced radiologist looked at multiple views, the rate increased to 73.6 percent. That still means that more than one-fourth of the osteolysis was missed.

X-ray can’t show osteolysis, the authors conclude, unless the defect is large and in just the right place. They advise using multiple X-ray views when looking for osteolysis. Even with these steps, the doctor should be prepared to miss more than half of all lesions along the back side of the hip socket.

Robots have been helping doctors replace joints since the early 1990s. ROBODOC is used for this operation. The purpose of this study is to report differences in results when using robotic-assisted versus manually implanted total hip replacements (THRs).

Doctors at a German hospital put 154 THRs in patients with osteoarthritis. Each patient got the same kind of implant to make the comparison possible. ROBODOC was used for the robotic-assisted operations. A planning software called ORTHODOC was also used.

The authors report longer operating time and more nerve damage with ROBODOC. The reamer also stops when it comes to areas of hardened bone and won’t restart. The doctors must take over at that point. Using a robotic reamer means that all soft tissue must be cut at the starting point. The reamer also cut into some layers of the hip tendons. This resulted in a higher rate of hip dislocations.

The robotic-assisted operation did give the patient a close fit of the implant to bone. Researchers aren’t sure if this makes a difference in the final results yet. The authors think robotic technology for joint replacement needs more work. Better and safer results are needed before using ROBODOC for everyone.