FAQ Category: Knee

You are probably referring to a procedure called ligament augmentation. A braided length of polypropylene (synthetic plastic) was used. The idea was to protect and reinforce the torn ligament until it could heal. The device was designed to be absorbed by the body. As the ligament healed, mechanical forces were transferred back to the repaired ligament.

Studies didn’t show an advantage to this method. The rate of surgical failures was high because the ligament augmentation device would rupture. Over time research showed that using a live tendon from another area of the knee as a graft worked much better. A simple repair of the torn ACL was abandoned as ineffective. All ACL repairs are augmented now; most are done arthroscopically without opening the knee.

Joint laxity after ACL repair occurs in about 10 to 30 percent of the patients who have a hamstring transplant. It usually has nothing to do with what the patient did or didn’t do.

To keep this from happening the surgeon tries to “tighten up” the reconstructed ligament during the operation. The problem is that the amount of tension to apply to the graft is unknown at this point.

Some surgeons warn that too much tension will increase the pressure on the knee too much. But studies show that the tension on the tendon graft tends to decrease by more than 50 percent with repeated use.

To prevent this from happening the graft is “preconditioned” before being used to repair the torn ACL. The tension is preset and the graft is kept at a lower temperature than normal body temperature. There may be a problem with this preparation. According to a recent study, once the tendon graft warms up to body temperature, it relaxes and loses some of its tension.

It seems there may be several variables at work here that the patient doesn’t have control over. More study is needed to find the right amount of tension to use with ACL repair and to find ways to hold it.

When the hamstring tendon is used to repair the ruptured anterior cruciate ligament, the donor graft is harvested early and “preconditioned.” Basically this means the graft is allowed to reach the same temperature of the operating room — about 20 to 30 degrees lower than the body temperature.

The idea is to increase the tension and stiffness of the tendon graft. Hamstring tendon grafts tend to loosen up more than patellar-tendon grafts. Setting the proper level of tension to start is important. The problem is no one knows just exactly what that is — and it may be different from patient to patient.

Most recently a study done on cadavers (bodies preserved after death for study) showed that cooled tendon grafts warm up once they are placed in the body. So maybe it’s better to keep the tendon grafts warm until implanted. Until an answer is found to this dilemma, surgeons will continue to precondition temperature and tension of tendon grafts in hopes of getting the right amount of joint stiffness and stability.

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.

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.

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.

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.

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.

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.

The surgeon will make every effort to get the infection under control and save the implant. If this doesn’t work then the implant may have to be removed. At this point treatment is still focused on clearing up the infection.

A revision surgery may be possible. After the implant is removed and the infection is under control, then a second implant may be inserted into the joint. If this is not possible, then a fusion may be needed.

With a fusion or knee arthrodesis, the patient can still put weight on that leg and walk but motion is very restricted. Getting in and out of a car or on and off a bus can be very difficult. Sometimes the surgeon has to shorten the leg so the patient can swing the leg through when walking.

Knee arthrodesis isn’t ideal but it does save the leg.

Treatment depends somewhat on your goals. If you are planning to return to competitive sports, then analgesics to control the pain and rehab may be your best options. However, you should be aware that without the meniscus, your knees are at increased risk for damage and changes from arthritis.

If possible, the meniscus is repaired rather than removed. Most patients are encouraged to put aside strenuous, high-impact activities to protect their joints.

For some younger patients, meniscal transplantation may be the answer. Cartilage freshly donated or stored in a frozen state may be used. The knee must be stable and in good alignment. There can’t be any bone spurs.

A surgeon will conduct a physical exam. How you stand and walk is evaluated. Knee joint motion and alignment are important. Too much angle at the knee may keep you from being a good candidate for this surgery.

This treatment option is only considered for younger patients (less than 40 years old). The down side is that long-term studies haven’t been done to show results 10, 20, or more years ater.

Talk with your doctor about what’s best for you given your age, activity level, and sporting goals.

Meniscal transplantation is a fairly new operation. Studies comparing the results using different rehab programs haven’t been reported. There’s no clear agreement on the best approach at this point.

In general you can expect some restrictions in motion and weight bearing until healing has taken place. This may take two to three months. Details of your rehab may vary depending on whether or not you have any other repairs done at the same time. Many patients with a torn meniscus also have a ruptured anterior cruciate ligament (ACL).

Motion is important after ACL repair to prevent scar tissue and adhesions from forming. Too much motion can disrupt the meniscal graft. Your doctor may prescribe a hinged knee brace for the first six weeks. The brace can be used to control how much weight and shear is put on the graft.

Patients can return to light work in about a week. Strenuous work can be resumed three to four months after the operation. Low-impact activities begin at eight weeks. Running is allowed after four to five months. Light sports are okay but high speed, high-impact activities are not allowed even after rehab is done.