FAQ Category: Knee

This has been an unresolved issue ever since the total knee replacement (TKR) was first done in 1968. Today 365,000 TKRs are done each year in the United States. At first the kneecap (patella) was replaced. Early problems with fracture, loosening, and rupture of the tendon around the patella caused surgeons to rethink this decision.

Some studies were done of patients who all had a resurfaced (replaced) patella. Others reported findings on studies with patients keeping their own patellae (nonresurfaced). A single answer to which was better couldn’t be reached.

It seems there are too many factors to compare. There are many different kinds of implants to choose from. Different surgeons come to the (operating) table, so-to-speak with a wide range of experience and surgical methods.

Even the patient’s diagnosis can make a difference. Some patients have one knee replaced while others have both knees replaced. It’s not always possible to tell if the results vary because of one of these factors or because the patella was or wasn’t replaced.

There remains a need for high quality studies to be done in this area of orthopedics.

Total knee replacement (TKR) has become a very popular way to treat pain and loss of function from osteoarthritis of the knee. Although the knee joint itself may need replacing, sometimes the kneecap (patella) is just fine. It moves up and down over the joint just fine.

Some researchers suggest it’s best to leave the patella alone when:

When the knee joint is replaced the surgeon has two choices about the kneecap (patella). He or she can leave the patient’s patella in place or remove it and replace it with an implant. Unresurfaced or nonresurfaced means the patient’s patella is cleaned up but left alone. Any bits of uneven bone are usually smoothed over. Pits and dings in the cartilage are also evened out.

If the patella is removed and replaced, then a plastic backed implant is used most often. Early patella replacements were made of metal but bits of metal kept breaking off causing problems.

One of the jobs of the anterior cruciate ligament (ACL) is to keep the lower leg bone (tibia) from sliding too far forward on the upper leg bone (femur). A weak, lax, or insufficient ACL means higher stress on the knee cartilage.

The medial meniscus is affected the most. This is the C-shaped piece of cartilage on the inner (medial) side of the knee joint. Repairing the ACL will unload the medial meniscus and make it less prone to further damage or degeneration.

Your surgeon will be able to guide you in making this decision based on your symptoms, the result of tests, and the peek he or she had inside the joint during the meniscal repair. The results of many studies suggest a better long-term result if the ligament is repaired either at the same time as the meniscal tear or soon after.

Graft material for bones and ligament come from two sources: from the patient (called an autograft or from a donor (allograft). An autograft of meniscal tissue isn’t possible at this time.

Scientists are working on removing a small number of cells and regenerating tissue in a laboratory that could be re-injected into the same patient. This is many years away yet.

Allografts are taken from donors who have died from injuries or acute disease. Most donors have been killed in a car accident or had a stroke.

The tissue is screened carefully for any diseases or infection. Tests can be done to look for hepatitis or HIV/AIDS. Donors must not have received steroids or other potent drugs prior to their death. Healthy donor tissue is frozen and matched to the candidate by size.

Research is underway to make an artificial (synthetic or plastic) meniscus.

Years ago a torn meniscus was just taken out. Since then we’ve discovered just how important this little C-shaped piece of cartilage is. Saving it and restoring the joint is the focus of treatment for knee meniscal injuries today.

Surgeons try to return patients to their former activity level. They understand the need to avoid future joint surgery.

One of the today’s more exciting developments in joint restoration is cartilage regeneration and transplantation. Cartilage transplants aren’t for everyone yet. Right
now younger, active patients with good joint alignment are the best candidates. They’ve either had 50 percent or more of the meniscus already removed or there’s a recent tear that can’t be repaired for some reason.

Cartilage transplantation isn’t offered everywhere. You’re in luck because the New York City area does have surgeons who are doing this type of work. You can go on-line and Google the words: ‘meniscus transplant New York City’ and find the centers that offer this service near you.

There may be several factors here. The type of graft and surgical repair can make a difference. Complications and older age can hold some people back. The biggest difference may be in compliance.

Studies show that as patients heal and recover, they are less likely to do their exercises. After three months only half the patients are still doing their exercises. Young, active, or aggressive patients who stick with the program seem to recover function and return to normal activities the fastest.

Keeping a log or diary of exercise may help boost compliance. Goals should be written down and revised as each one is met. Number of exercise sets, repetitions, and sessions can be recorded. This gives patients a sense of accomplishment and can help them move along faster. Patients working with a physical therapist or athletic trainer can have the rehab specialist review the log on a weekly basis and advance the program.

There are many ways to assess knee function after anterior cruciate ligament (ACL)repair. Range of motion, function, and strength are the main tests. The single-legged hop test is an accurate test of power. It’s a good test to compare one side to the other.

The test is done by having the patient hop as far as possible just on one leg. The patient’s arms are fee to use for balance while taking off and landing on that foot.
Number of feet hopped is measured and compared to the other side.

At six months post-op you should have no problems completing this test. You should be concerned if you’re leg is giving out from underneath you during regular walking or other activities. If you’ve followed a standard rehab program you should have stressed the knee like this during your exercise program.

Talk to your therapist about your concerns. Perhaps you aren’t ready for this test and
need some more time to progress your exercise program. You can certainly practice hopping under the therapist’s supervision. Most clinics have a pair of parallel bars you can use to hold on to during practice sessions until you feel the confidence you need to complete
the test.

Most veteran amputees incurred from trauma while on active duty receive their care and prostheses paid for by the Veteran’s Administration (VA). The requirements are that your husband enroll in a VA clinic and attend regular follow-up care.

Taking part in formal studies is not required but certainly helpful for others. Information gathered from these studies helps the VA provide better care for war veterans wounded in the line of duty. If it’s an ongoing study you may be able to enter at a later date when it’s more convenient for your family.

Talk to the study coordinator and find out what are your options.

Increased walking speed isn’t uncommon in leg amputees using a prosthesis. A prosthesis is an artificial limb or part of a limb. Changing the walking speed may be a way to compensate for the uneven gait pattern that develops when using a prosthetic device. By walking faster, the person shortens the stride length and equals out both sides.

When walking, the person with a prosthesis tends to shift the weight over to the normal or intact leg. The problem with this strategy is that over time, the nonamputated knee absorbs the force and is at increased risk for osteoarthritis.

Gait training and/or adjusting the prosthesis may help your husband even out the load on both legs and avoid future injury. A physical therapist can help you with this problem.

Much has happened in the world of anterior cruciate ligament (ACL) repair and rehab in the last 20 years. Years ago we thought the leg had to be immobilized while the graft healed. Now we know that early movement is the best form of rehab possible.

Today patients are allowed to move the knee as much as possible. They can put as much weight on the leg as tolerated. Many patients return to unrestricted activities within six months of the surgery.

A recent study comparing regular rehab (32 weeks) to an accelerated program (19 weeks) showed no difference in joint laxity between the two groups at the end of one and two years. The concern in speeding up rehab is that the graft will get stretched out and the joint will be too loose. Joint laxity wasn’t a problem for the accelerated group in this study.

ACL rehab will continue to change and progress as research shows just what the limits are for healing and recovery after ACL repair.

Arthroscopic examination of the knee is done with a needle inserted into the joint. There’s a tiny TV camera on the end of the scope giving the doctor a view inside the joint. The test is usually very accurate.

The arthroscopic exam may be considered “negative” (normal) if and when the tear is small and remains flat against the rest of the meniscus. This is called a nondisplaced tear.

Meniscal tears are graded based on their location, direction of tear, and depth of injury. A horizontal partial-thickness tear may remain undetected when nondisplaced.

It’s also the case that mild tears can become severe tears with re-injury. If your arthroscopic surgery was done before the tear was complete then a false-negative test may be obtained. This means the test was negative for a meniscal tear when there was a tear after all.

There are several common orthopedic tests done in the clinic for meniscal tears. Joint line tenderness is 89 percent accurate in finding lateral meniscal tears. McMurray’s test is a popular one. The patient is lying on his or her back. The examiner puts mild compressive stress in a valgus or varus direction. This is done while moving the knee from a bent to straight position and rotating the tibia.

Any loose fragments or tears in the meniscus will cause a snap or click. This response is often painful for the patient.

Another test is Apley’s compression and distraction. This test is done with the patient lying face down. The knee is bent 90 degrees. The examiner uses his or her knee to gently, but firmly, hold the patient’s thigh down. The tibia (lower leg) is distracted and the foot is used to turn the tibia in and out. Look for any catching, pain, or restricted movement. The test is repeated with the tibia compressed (push down on the foot while rotating in and out).

Any changes while the knee is compressed are likely to be meniscus. Positive signs with distraction and rotation may be ligamentous.

A new test called the Thessaly test has been shown to be 94 to 96 percent accurate. The patient stands barefoot on one leg (test the normal leg first). While holding the examiner’s hands or a stationary object, the patient bends the knee five degrees and keeps it there while rotating the knee and body internally and externally, three times.

The same test is repeated with the knee bent 20 degrees. Patients with meniscal injuries are likely to have joint-line pain or discomfort during this movement. There maybe a sense of locking or catching. Beware that in the rare case the knee can get locked up and require surgery to unlock it.

Damage to the meniscus is fairly easy to diagnose based on the patient’s history and a few clinical tests. The most common history is a twisting injury of the knee with the foot planted firmly on the ground. The knee is usually bent when this happens. Pain occurs along with swelling that comes and goes and a locking sensation for some patients.

Some of the tests used by doctors, therapists, and athletic trainers to test for meniscal tears have a high rate of false-positive findings. This means the test is positive for a meniscal tear when no tear is present.

No test is fool proof but joint line tenderness along the outer edge of the joint can be safely used to detect a lateral meniscus tear. Joint line tenderness for any meniscal tear is less reliable when there’s an anterior cruciate ligament (ACL) tear also present at the same time.

The most reliable test may be a new one. The Thessaly test has been shown to be 94 to 96 percent accurate with knee meniscus. The need for an expensive MRI may be replaced by this new first line screening exam.

Total knee replacement (TKR) has some very positive outcomes. Besides pain relief, patients often report improved motion and increased function. Most of these patients started from a place of severe disability. Having come from a very inactive lifestyle, their expectations may be less than yours.

Despite good outcomes research shows there are some long-term problems after TKR. Walking speed and stair-climbing speed are as much as 50 percent slower in patients with TKR compared to those without a TKR. Quadriceps weakness and atrophy may account for these changes.

Long-term studies of patients with TKR show continued improvement of muscle activity up to three years later. Even so, the level of voluntary muscle contraction doesn’t seem to come up to the level of healthy adults of the same age without a TKR. You may be having this problem.

Perhaps it’s time for some formal muscle strength testing if this hasn’t already been done. Ask your doctor for a more precise time frame for expected recovery and request muscle testing with a physical therapist. Getting a baseline even now can help you track your progress and find the right exercise program for you.

Doctors and therapists have long thought that patients are weak in the early days and weeks after total knee replacement (TKR) because of pain. Efforts are made to reduce pain quickly. The idea is gaining control of pain will help restore motion and improve function. But according to a new study, pain control may not be enough to prevent loss of muscle strength.

Muscle atrophy and lack of activation may be the real culprits. Surgical trauma causes muscle inhibition. The leg muscles are unable to contract. This is called failure of voluntary muscle activation.

A recent study of 20 patients before and after TKR showed a big loss of force-producing ability by the quadriceps muscle. Measurements of muscle contraction were taken 10 days before and one month after the operation.

They found quadriceps strength was down by 62 percent despite an active rehab program. Improving strength may require a different kind of exercise program–one that gets each muscle fiber to contract.

No doubt your exercise program has helped you. It may be time to look into a different kind of exercise now. Talk to your doctor and your therapist about the use of biofeedback or electrical stimulation to activate muscle recruitment.

Actually, a recent study from the University of Florida showed that knee pain is a very small part of the problem. The real issue is a loss of muscle activation and strength. The quadriceps muscle along the front of the thigh seems to be affected the most.

You may do best with a program of physical therapy to improve muscle activation. High-intensity muscle contractions is the first place to start. Biofeedback and electrical stimulation may help too.

Check with your doctor first about pain control. After four months your pain level should be more manageable. Then ask about a follow-up rehab program to address the problem of muscle atrophy and weakness.

Unicompartmental knee replacement (UKR) was first tried in the 1970s. The early results weren’t too good. Since then surgical tools and techniques have improved. Surgeons are using this approach more often now.

One problem that occurs is over correction of the joint. Some surgeons release a ligament on the medial (inside) edge of the knee when replacing the joint on that side. This transfers force to the other (outer) surface of the joint. The joint gets damaged and shows a loss of joint space.

In some cases there was already the start of arthritic damage to the side that wasn’t replaced. Time and activity continue to take their toll on the remaining joint until the person develops painful symptoms.

This problem doesn’t happen a lot but with the increasing number of UKRs being done, we may see the condition more often.

You may be a good candidate for revision surgery. If the replaced side still looks healthy on X-ray, then a tricompartmental revision surgery might be recommended. In this case, the other half of the knee is replaced along with the kneecap.

You would end up with a total joint replacement, but it would come in three component parts. If there is too much wear and tear or loosening of the UKR it may be necessary to remove the UKR and replace the entire joint with a total knee replacement (TKR).

See your orthopedic surgeon for an evaluation and find out what are your options. You may be a good candidate for rehab or revision surgery. Knee replacement surgery has improved even in the last six years.

In medical terms the condition you are describing is called genu valgus. This knee deformity causes a transfer of weight to the inner (medial) side of the joint when it would otherwise be spread more evenly across the joint.

Arthritis on just one side of the joint can occur. This is called unicompartmental arthritis. Osteotomy is frequently done for this problem. An osteotomy attempts to transfer the forces of the body weight onto the normal, non-arthritic side, by actually changing the angle of the bone.

This is done by cutting a wedge-shaped piece out of the bone and inserting it on the collapsed side. This is called an opening wedge osteotomy. Or it can be done by cutting out a wedge and collapsing the gap on the other side (closing wedge) osteotomy. Opening wedge is the more commonly done operation.

If this operation can’t be done for some reason, then unicompartmental knee replacement (UKR) is another option. The damaged half of the joint is removed and replaced by a single-sided joint replacement. For genu valgus, just the medial side of the joint is replaced.

The first step is to see an orthopedic surgeon for an exam. X-rays will likely be taken and then the best treatment plan can be determined.