FAQ Category: Knee

There are several tests used to measure hip flexor flexibility. An athletic trainer, physical therapist, or orthopedic surgeon can test you.

One test is called the Thomas flexion test. You lie down on your back on a table with a firm surface. The crease of your buttock should be at the edge of the table. Bring both knees up to your chest. Keeping your back flat on the table, lower one leg until it is straight out. Lower that leg toward the tabletop as much as you can without arching your low back or letting your pelvic bone tilt.

A tight hip flexor muscle will keep you from lowering your leg all the way down to the table. A flexible person will be able to get to a horizontal (normal) or beyond horizontal position (hyperflexible). The physical therapist uses a tool called a goniometer to measure the hip angle during this test.

Another test is the Ober test used to measure flexibility of the iliotibial band (ITB). This band of fascial tissue comes down along the side of the leg from hip to knee. For this test, you lie on your side with the leg in question on top. The lower leg can be bent to help support you on the table.

The upper leg is bent 90 degrees at the knee. The therapist lifts the leg away from the body to a horizontal position and then extends it backwards slightly. The leg is then lowered toward the table until it starts to rotate or can’t go any further.

A normal amount of motion allows the leg to be placed in the horizontal position. With a tight ITB, the leg stays up and won’t drop down towards the table. The extra flexible person can touch the knee to the table.

Treatment for patellofemoral pain syndrome (PFPS) has traditionally relied on quadriceps strength training. Some patients also benefit from neuromuscular training, which focuses more on motor control than improving strength.

So far no one has found a “one size fits all” kind of program. Some people seem to get better with one type of exercise while others have less pain and more function with other types of training.

Some time ago researchers saw that hip strength may be an important key to PFPS. One by one studies have been done to confirm this suspicion. Most recently physical therapists at the Nicholas Institute of Sports and Medicine and Athletic Trauma in New York City studied hip strength and flexibility as it relates to PFPS.

They found that 60 percent of patients with PFPS got better after a six-week training program. Exercises to improve hip flexor strength and flexibility resulted in decreased pain and improved function.

The goal was to prevent inward rotation of the thighbone (femoral rotation). Maintaining good alignment of the patella as it moves up and down over the knee reduces the tension on the soft tissues around the knee. This new treatment approach may help you as well!

Artificial cartilage is still in the laboratory and in experimental studies. Some surgeons are using allograft tissue for young patients with severe meniscal damage. Allograft means it comes from a donor. In this case cadaver tissue is used (meniscus harvested after the donor’s death).

Careful rehab after the transplant can result in return to normal activities including sports. The implant is not foolproof however. New trauma can cause a new tear or injury to the allograft. Surgery to repair it may be all that’s needed. But a complete tear may result in allograft removal.

Postoperative tears are more common in older patients and in people who’ve had multiple knee surgeries already. Most patients have a good to excellent result with graft survival in 90 percent of recent cases reported.

Sometimes it’s impossible to tell the serious from the not-so-serious medical conditions. With aging come age-related changes in the body. With the knee, joint cartilage such as the meniscus starts to wear out. Early signs of arthritis start to set in.

But most experts agree that early intervention can make a big difference in many kinds of problems. Don’t wait to see your doctor. An X-ray may be all that’s needed. In some cases an MRI is best. If conservative care doesn’t improve your symptoms, then a second MRI may be needed.

Recently several studies have documented cases of spontaneous osteonecrosis in adults over age 60 who had some meniscus degeneration. Osteonecrosis is the death of bone. Spontaneous means it came on suddenly with no warning and no known cause. These are the kinds of problems you want to avoid by checking with your doctor sooner than later.

You’re not alone in your questions. We know that osteonecrosis is the death of bone tissue. But spontaneous osteonecrosis (SON) is sudden, unexpected, and without known cause.

Some recent reports point to a possible increase in this condition in adults over age 60. At first doctors thought it was linked with arthroscopic surgery to remove a torn meniscus. But then five new cases were reported in patients who had meniscus degeneration but no surgery.

It appears that age-related wear and tear on the meniscus may be the start of the problem. But there are still many questions about what’s going on. For example, in one study of five patients, symptoms of knee pain were identified as medial meniscal degeneration.

At the time of the diagnosis, there were no changes in the bone seen on an MRI. The patients were all treated with physical therapy, exercise, and noninflammatory drugs. Two months later the symptoms increased. A second MRI showed osteonecrosis of the knee.

What happened in those two months between MRIs? Doctors just aren’t sure yet but further studies may offer some insight into SON.

Scientists studying the field of tissue engineering are very interested in knowing the answer to your question. If we can understand the normal pathways of tissue healing, then maybe we can find a way for ligaments like the ACL to repair itself.

The poor healing capacity of the ACL can be explained in part by its biology. First there is a very thin lining or sheath around the ACL. Once this sheath is disrupted, the blood supply to the ligament is decreased greatly.

Normal healing and repair depend on the formation of a hematoma. A hematoma is a collection of blood cells trapped in the tissues after trauma or injury. Somehow the presence of the hematoma sets up the right environment needed for tissue healing. Without a blood supply, there can be no hematoma formation.

The hematoma provides a base camp so-to-speak for local growth factors and chemicals to come and set up a mesh or scaffold. Cells fill in around the scaffold forming collagen and scar tissue. It looks like there’s a complex interchange between repair cells, growth chemicals, and the scaffold needed for healing. Without the hematoma to get the process started, ligaments don’t recover on their own.

You’re right that synthetic graft materials have been studied since the early 1970s. The Food and Drug Administration (FDA) even approved the first one at that time. Since then, various companies have come out with ligament implants.

Everything started out good with a stiff graft that gave the knee the strength it needed. But over time, there were many problems. For example, graft rejection was common as the body saw the implant as a foreign body to get rid of. Inflammation and rupture ended the use of the early ligament replacements.

Later new ligament implants were designed to promote tissue ingrowth. As the body filled in with its own tissue the new ligament was part natural, part manmade (synthetic). The same thing happened with inflammation and graft failure.

Tissue engineering continues to progress as an area of study. Scientists are trying to develop tissues to replace nerve, skin, heart valves, liver, and bladder. Orthopedic surgeons are very interested in tissue that could help with fracture healing. Injury to tendon, cartilage, and ligaments like the ACL would be the next natural step. For now, research remains in the experimental stage and isn’t ready for human use yet.

Surgeons are starting to take a second look at ways to repair cartilage that were tried and abandoned years ago. Doctors used to resurface the bone by cutting away the top layer down to the blood vessels.

Once the bone started bleeding, blood clots formed and healing would take place. The hope was that new cartilage would form, too. But too many patients ended up with more instead of less pain so the doctors stopped using this procedure.

Turns out they were really on to something and stopped too soon. Removing too much bone was the problem. Drilling and cutting were also counter productive. Shaving or abrading (but not too deep) really did stimulate cartilage repair.

Cartilage repair techniques using abrasion arthroplasty as this method is called may be something that could work for you. Make an appointment with your orthopedic surgeon and find out what your options are.

There are some other newer procedures that are being used with good results for patients like you, too. Ask about using chondroitin-glucosamine (shark cartilage) supplements and hyaluronic acid injections. If you have any cartilage left at all, these treatments may help cartilage heal. You may be a good candidate for one or both of these treatment options.

You are indeed correct in what you heard. Some 15-year follow-up studies have shown an 80 to 95 percent success rate with osteochondral allografts (OCA). These results occur when the tissue is harvested within 24 hours of the donor’s death. The graft must be used within seven days for the best results.

Donated OCAs can be preserved or saved using different methods. Prolonged preservation for up to 28-days has been shown to be acceptable. Positive long-term results still range in the 79 to 84 percent with “older” grafts.

Using OCAs more than 28 days after harvesting from the donor is not advised at this time. Patient satisfaction measured by symptoms and activity level is much less when grafts are more than 28 days old.

Osteochondral allograft (OCA) transplantation is a fairly new treatment approach for severe cartilage damage to the knee. Some surgeons are also using it in the shoulder.

A plug of bone topped by the joint cartilage is removed from a donor within 24 hours of his or her death. The graft can be saved and used for up to 28 days.

Postoperative rehab is important. Continuous active motion is advised. The patient is given a series of exercises that must be done every waking hour. Athletes are slowly prepared to engage in competitive sports. High-impact activities aren’t allowed for at least a year.

It takes this long before the graft is fully accepted and grafted as part of the body tissue. Until then the player is benched. Training and sports play can resume when X-rays confirm a successful graft acceptance. Each surgeon will have his or her own protocol, which may vary from what is presented here. Be sure to ask your surgeon for an outline of what to expect in this area.

Studies show that high-volume surgeons operating at high-volume hospitals have the best results with total knee replacements (TKRs).

Presumably this means that doctors who do the surgery more often have better results. Care given at high volume teaching or university hospitals seems to come with lower death rates and fewer infections.

Exactly what the differences are between high and low volume hospitals remains to be investigated. Hospital resources and clinical pathways (the way they do things) may be the difference. More study is needed to sort out which aspects of care delivered at high volume institutions results in better outcomes.

For now the results of these studies suggest choosing your surgeon is the first and most important step. Taking a look at the type and size of hospital may also be important. Family support is a final factor that should be included in your decision. If your family can’t travel to be with you at the larger hospital, then the local hospital may be the trade off needed to ensure the best care all around.

Researchers are studying many problems patients face with the idea of predicting who will have a good/poor result. The hope is to give the right care to each group to get the most benefit.

When it comes to total knee replacements (TKRs), there are quite a few studies already done on this topic. One of the most recent ones looked at over 200,000 patients who had a TKR between 1991 and 2001. Rates of infection, blood clots, and death were compiled. Factors such as age, gender, health, and type of insurance were matched against the data.

They reported that age over 65 was a risk factor for problems. Likewise, patients with more than one other health problem had worse outcomes. High blood pressure, diabetes, and a previous history of blood clot(s) are all risk factors for problems after surgery.

Previous studies have shown that surgeon experience makes a difference. Surgeons who do more TKRs have the best results. It turns out that hospitals have similar track records. High volume hospitals have the lowest death rate and rate of infection after TKRs.

Your father-in-law’s best chances for a good recovery depend on his health, his surgeon’s skill, and the type of hospital he will be staying at. Type of insurance seems to have an impact, too. Medicare patients have worse results than patients covered by private insurance.

Anterior cruciate ligament (ACL) repairs have indeed been around for 30 years or more. Surgeons keep finding ways to improve it. In a recent review of ACL repairs, Dr. Ben Graf from the University of Wisconsin (Madison) gave a good summary of the last 30 years.

He said the first 10 years was spent proving ACL repairs were needed. The second 10 years worked on repairing it from the inside out. And the last decade has been looking at types of grafts (hamstring versus patellar tendon grafts).

The newest change is the use of a double-bundle repair to (maybe) replace the single-bundle method. No matter what kind of graft type used, there’s still a problem with early arthritis in the grafted knee. By studying normal anatomy, scientists think this may have to do with motion that is restricted by the ACL repair.

It seems that the standard single-bundle repair doesn’t allow the normal rotation of the tibia (lower leg bone). This type of motion is needed when an athlete pivots and shifts his or her weight to move in a different direction. The double-bundle repair attaches the tendon graft in two places instead of one. The idea is to mimic the anterior and posterior (front and back) attachments of the normal ACL.

But like many new things on the horizon, this one hasn’t been fully tested and approved. The next decade may bring many innovative changes. Improved technology and new surgical instruments will bring about these changes.

Not to worry. The new double-bundle method is still in its early stages and may not be any better than the single-bundle repair your son had. With double-bundle repairs, the tendon graft is divided into two parts. The intent is to mimic the normal or natural anatomy, which has an anterior and posterior attachment of the same ligament.

Many surgeons say that the current single-bundle method gives good results when done well. In the hands of a good surgeon who does lots of these operations, the outcome is good to excellent.

The single-bundle repair is just as stable as the double-bundle. Most surgeons will tell you the typical athlete is more likely to injure the other knee than to reinjure the ACL repair.

Only highly trained specialists are even doing the double-bundle repair. Most orthopedic surgeons are using the single-bundled repair. So the jury is still out on the new double-bundle method.

You may be referring to abrasion arthroplasty a technique started more than 25 years ago to stimulate repair of damaged cartilage. Surgeons would cut away the top layer of damaged cartilage and bone in a joint to cause bleeding. The idea was to bring about healing and regrowth of the bone and cartilage.

The problem was they took too much bone and left the patient with a weak bone and a painful knee. So abrasion arthroplasty to reconstruct joint cartilage fell by the wayside.

Today surgeons are taking a second look at this method of cartilage repair. They’ve discovered that shaving the bone instead of cutting or drilling has the desired effect.

Patients who’ve had this type of arthroplasty can put off joint replacement by 10 to 12 or more years. And when they do have the joint replaced, the underlying bone is in better condition than expected.

You may be talking about the minimally invasive (MIS) quadriceps-sparing total knee replacement (TKR). In the standard TKR operation the quadriceps muscle in front of the knee and thigh is either split open or cut and moved out of the way while replacing the joint.

Problems can occur when the muscle is disrupted this way. Blood vessels and nerves can be cut causing swelling and weakness after the operation. Quadriceps sparing doesn’t avoid the muscle completely, but it reduces the amount of trauma by quite a bit.

Patients with rheumatoid arthritis who do not have osteoporosis can have this operation. Younger patients with normal weight and no knee deformity have the best chances of a good result from surgery.

Joints damaged by arthritis become uneven, thin, and worn down. Replacing the cartilage and the subchondral layer of bone just under the cartilage is an example of resurfacing.

‘Biologic’ resurfacing means that live tissue grafts are used. The layer of bone and cartilage used is called an osteochondral allograft. Allograft means it comes from a donor after death.

Synthetic resurfacing would replace the damaged cartilage and bone with a thin layer of plastic such as polyethylene used with a joint replacement.

There are a few small studies reporting the results of osteochondral allografts for severe patellofemoral (PF) osteoarthritis (OA). Osteochondral refers to bone and cartilage. Allograft means someone else donates the tissue. The top layer of bone and attached cartilage forming a shell are harvested from a donor.

The damaged bone and cartilage are removed so the graft can be inserted. Sometimes just the patella (kneecap) is replaced. This is called a unipolar graft. Bipolar grafts are also possible. This type of graft replaces both the patella and the upper half or femoral surface of the joint.

Results so far have been encouraging. Most of the patients have been able to delay the total knee replacement by as much as 10 years. Symptoms and function improve enough to make it worth doing.

Ask your doctor what are your options. Sometimes just removing the patella is helpful. In other cases aligning the joint with an osteotomy may be possible. During the osteotomy a small wedge-shaped piece of bone is removed from one side of the knee and inserted into the other side. This changes the angle of the joint and may help relieve symptoms. If you’ve already had these operations done without success, then biologic resurfacing may be the next choice for you.

Alignment is one of the most difficult aspects of knee joint replacements for the surgeon. Instruments used to make the bone cuts are based on average bone shape. But bone size and shape can vary from patient to patient.

The surgeon can’t always tell when a joint with a new implant is still slightly flexed at the end of the operation. In fact it can be bent as much as 10 degrees when fitting the implant in but look straight. There is also a tendency to internally rotate the upper (femoral) half of the implant. The result is often loosening and failure of the prosthesis.

Scientists are working with surgeons to limit and eventually eliminate this problem. The use of 3-D computer programs before surgery may help surgeons plan ahead. Plotting out when and where to make bone cuts and forming a template of the patient’s joint may help improve accuracy of alignment.

Resection arthroplasty is the removal of an implant or prosthesis. In this case, the total joint replacement will be taken out. This is one treatment option for patients with a failed total knee replacement.

During the operation the surgeon will remove all parts of the implant including the cement. The joint is cleaned very carefully. Any infection, torn soft tissue, or rough edges of bone are removed. The ends of the bone are carefully shaped to come in contact with each other.

The patient is put in a cast and uses a brace when the cast comes off. The patient can bend and straighten the knee a little. In a small number of cases the joint may fuse itself.

Once the infection is cleared up, the surgeon may try to insert a second implant. If the joint is too unstable then the joint may need to be fused surgically. This is called a arthrodesis.