News Category: Knee

It may seem like the knee just bends and straightens, but there are actually six directions of movement in the knee. Each one is around a central point or axis. With six movements, the knee has motion around multiple axes. These include moving forward and back, side to side, and turning (rotating) in or out. Likewise, the muscles around the knee contract to create these six directions of movement.

Knowing about these motions is important when treating knee injuries. For example, it is well known that straightening or “extending” the knee is a problem after anterior cruciate ligament (ACL) injury. The muscle that controls knee extension (quadriceps) is weak after injury and takes a long time to recover. Much of rehabilitation is focused on this area.

Researchers wanted to know if other motions were also changed by ACL injury. How does the knee compensate for the loss of this ligament and the reduced muscle strength? Researchers looked at changes in knee motion at three different stages of injury or repair: (1) right after the injury, (2) when the knee injury was “chronic” and had not been repaired, and (3) after surgery to repair or reconstruct the ligament.

There were several interesting observations. First, the knee didn’t move in one direction without some movement or force in the other axes. This was also true of the muscles, so that one motion created a reaction in the other muscles around the knee. In the case of surgery, muscle strength gradually increased in all six directions from one month to one year after surgery. Knee extension was the slowest to recover.

In the case of a chronic ligament tear, the knee tried to take the load off the injured ligament. It also avoided knee positions that were unstable because of the damaged ligament. The knee does this by increasing the amount of outward rotation of the lower leg bone (tibia) as it joins the knee joint. This “unloads” the ligament and muscles. In the case of early injury, there hasn’t been enough time for the knee to make this change. After surgery, there is a small increase in outward rotation, but not as much as with long-term injury.

Knowing about these changes or adaptations helps with treatment. Added emphasis can be placed on strengthening the muscles that help protect and unload the ACL. These include the muscles around the knee, the muscles of the lower leg, and even the hip muscles. These exercises can be applied after surgery, too. In this way, the reconstructed ligament can be protected and the chances of reinjury reduced.

The knee really depends on the muscles around it for stability. It also depends on the ligaments inside the joint to help hold it together. The surfaces of the two major bones that connect to form the knee are not smooth, perfectly matched surfaces. This is especially true on the outside edge of the knee joint. That’s one main reason the knee needs strong muscles and ligaments. These structures are at risk for injury because large or sudden forces at the knee can disrupt the ligaments. The anterior cruciate ligament (ACL) of the knee is especially prone to injury.

Anything that injures the muscles or ligaments can affect the knee’s ability to sense its position as it moves. This “position sense” is called proprioception. Proprioception can be difficult to measure. One way to measure it is to compare the point in time when the leg begins to move with when that motion is detected by the person. Physical therapists often measure proprioception by moving a patient’s leg into a position and then asking the patient to move his or her other leg into the same position without looking.

Studies have shown that not everyone with knee injuries has this type of damage. People with chronic unrepaired ACL tears have changes in knee proprioception. Some people who have had surgery to repair the ACL also have this type of damage. Researchers think that proprioception is impaired in more cases, but the difficulty of measuring it prevents them from proving it.

One group of researchers looked at the effects of bracing and bandaging on knee proprioception. They chose a group of people with ACL injuries that had been surgically repaired. They also looked at the results of other similar studies. There were a variety of results. Some studies reported no loss of proprioception after injury or surgery. Others showed loss of proprioception and improvement with bandaging the knee.

In their own study, these authors found that bracing did not produce any changes in detecting motion after surgery. Patients were measured after surgery and two years later. Differences in research results may be explained by differences in injury, differences in surgery, and when or how measurements were taken.

Does wearing a brace after ACL injury and/or surgery help improve position sense? More studies are needed to help clear up the confusion on this issue. For now, a brace of some type seems most helpful for patients who continue to have pain and problems and do not choose surgery.

If you could reduce your chances of having a knee injury while playing soccer, would you do it? There’s a new training program that has proven effective in preventing anterior cruciate ligament (ACL) tears. The ACL ligament in the knee can be injured during practice or competitive games. An ACL tear can happen with or without contact with another player.

A large study in Italy showed that when players received specific exercise training, ACL injuries were reduced dramatically. In a group of 300 players who did not receive this training, 70 wound up with ACL injuries. By comparison, only ten players who’d gotten the training reported ACL injuries.

How did the exercise training work? The researchers recognized the need for a program that included more than just the knee. They included the upper body, hip, knee, and ankle. There were exercises to improve the speed and strength of muscle contractions. Getting a total body response is essential in reducing or counteracting the strain that could otherwise cause an ACL injury.

Exercises to fine-tune the knee and ankle joints were also included. Inside each joint are two separate mechanisms that tell the joint where it is and how it is moving. These are called proprioception (sense of position) and kinesthesia (sense of movement). These mechanisms allow the athlete to make quick changes in speed and direction. They are especially important in a game like soccer and can be developed with coordination training, jump training, and a special training board.

The training board is a round disk or rectangular-shaped board with a half ball attached underneath. It challenges balance and weight shifting. By standing on one foot, athletes in this study had to keep the board balanced. This required using many different foot, ankle, and knee positions. Repeating the movements reduced the muscle fatigue that can interfere with proprioceptive responses. 

Giving soccer players an exercise program to prevent ACL injuries is important. ACL injuries cause the most days absent from play and cost more than most injuries. The exercise routine should put the athlete in situations that require fast reactions to expected and unexpected changes. This helps the player respond quickly when suddenly pushed off balance by another player. The player also responds more quickly and with greater strength when making sudden changes in direction or speed.

Next time you watch a soccer team, you’ll have a new appreciation for what they are doing while running up and down the field. Think about the finely tuned mechanisms in the joints and muscles that allow them to stop on a dime and head in the other direction.

You’ve had surgery on your knee to repair a torn anterior cruciate ligament (ACL). Now you’re being sent to physical therapy for weeks of exercise. At first it’s fun and interesting, but after a short while, you’re bored and wonder: Do I really need to keep doing this? Won’t my leg just get better on its own?

Physical therapists want the answers to those questions, too–and more! How soon after surgery can exercise begin? What types of exercises are necessary, and exactly what does each exercise do for the knee? Many new studies aimed at answering these questions are being reported.

This information will help physical therapists plan the right exercise program for each type of surgery. For example, in the case of the knee, exercises will be different for a weak ligament than for a ligament that has been repaired surgically. Therapists have been studying the ACL of the knee. They have developed a particular kind of exercise called neuromuscular training that may be useful after ACL surgery.

Neuromuscular training is used to help the muscles respond quickly and without “thinking.” If you need to stop suddenly, your muscles must react with just the right amount of speed, control, and direction. After knee surgery, this ability doesn’t come back completely without exercise.

Neuromuscular training includes exercises to improve balance, joint control, muscle strength and power, and agility. Agility makes it possible to change directions quickly, go faster or slower, and improve starting and stopping. These are important for walking, running, and jumping, and especially for sports performance.

The results of numerous studies show that neuromuscular training shortens the time it takes for muscles to react. This kind of exercise also increases the speed of muscle contraction, maintains knee function over six months, and reduces the number of knee injuries in the long run.

This information is just the tip of the iceberg for physical therapists. More research is needed to show which exercises help coordinate the muscles for walking, running, and other activities after ACL surgery. Therapists are studying how long it takes to return to pre-injury activity levels when doing neuromuscular exercises. Studies showing how long to do each exercise and the effects of activities other than exercise are also underway. 

It’s like your mother always told you: eat your vegetables, drink plenty of water, and oh yes, follow your therapist’s advice about exercise.

Even though doctors have been doing knee surgery for years, they never stop trying to improve their techniques. This is especially true in repairs of the anterior cruciate ligament (ACL), a major ligament in the knee. The surgeon can use tissue from another part of the knee to repair the torn ligament. Moving tendon tissue from one place to another is called grafting.

There are two grafts commonly used to repair a torn ACL. One is a strip of the patellar tendon below the kneecap. The other is from the hamstring tendon along the inside edge of the knee. For a long time, the patellar tendon was the preferred choice because it’s easy to get to, holds well in its new location, and heals fast. One big drawback to grafting the patellar tendon is pain at the front of the knee after surgery. This can be severe enough to prevent any pressure on the knee, such as kneeling.

For this reason, more doctors are using grafted tissue from the hamstring tendon. There are no major differences in the final results of these two methods. When it comes to symptoms after surgery, joint strength or stability, and ability to use the knee, either method is good. However, with the hamstring tendon graft, there are no problems kneeling and no pain in the front of the knee.

Patients who have patellar tendon grafts return to sports more often than those who get the hamstring graft. But pain in the front of the knee can hamper full function of the quadriceps muscle for patients with patellar tendon grafts. Those receiving the hamstring graft generally have more hamstring muscle weakness after surgery. Most people agree that the drawbacks to the hamstring graft are minor compared to the knee pain and difficulty kneeling that comes with the patellar graft.

A torn ACL may need surgery to repair it. Two graft choices have important advantages and disadvantages. Each doctor and patient should discuss these and decide what is best. If kneeling is important, the hamstring graft should be considered. This is especially true for people in certain occupations and sports.

Anyone who receives a hamstring tendon graft should follow a progressive strengthening program for the muscles that bend the knee. This should be included in rehabilitation and continue even when the patient has returned to regular sports and activities.

Would you have a knee replacement if it wasn’t going to make you feel better? Not likely! How do doctors know if replacing a knee joint is the answer for severe arthritis? They do tests. Patients and insurance companies want real evidence to show that treatments are effective. Health care workers are looking at all the tests available that measure patients’ results. Each health problem is different and may need a different test to measure results.

No matter what tests are used, research requires that they are valid and reliable. “Valid” means a test is a true measure of the thing in question. “Reliable” means the results can be trusted. If the test is given a second time, the results should be the same. In the case of health care issues, a third part is necessary. This is the before-and-after measure, or a measure of change over time. Researchers call this “responsiveness.”

Measuring responsiveness is a fairly new part of the picture. There aren’t very many studies to show health care workers which tests work the best to measure responsiveness. A group of scientists in Canada set out to identify these tests. They studied patients who had total knee replacement for arthritis. Tests were done before surgery, after surgery, and during the entire study period (beginning to end).

Two areas were studied: patients’ function and quality of life. “Function” is what a person can do physically. In this case, walking and climbing stairs were used as measures of improvement or responsiveness. “Quality of life” includes how satisfied the patient is before and after surgery. Other quality of life measures include amount of pain or ability to sleep at night.

The researchers found that different tests were better measures of change at different points in the process. Some were better measures of function or quality of life before surgery. Others registered small changes right after surgery. Still other tests were better when used from start to finish.

For example, stair climbing turned out to be too difficult for some patients to do even two months after surgery. Walking was also hard–and so not the best measure of change. Easier activities of daily living were better measures of the rapid changes that can happen after total knee replacement.

Tests that measure small but important changes soon after total knee replacement have been identified. These tools can be used by doctors and physical therapists to show patient responsiveness during the first few months after surgery. Quality of life is also accepted as a valid measure of improvement since this is what is important to patients. Knowing what kinds of changes to expect after surgery can help doctors and patients to plan treatment.

Have you torn the meniscus in your knee? Wondering whether to repair or remove it? Here are some findings that may help. Seventy-five people who had the lateral meniscus (the outside rim of cartilage in the knee) removed were examined between five and 15 years later. No other injury occurred in these knees. Only the torn or damaged part was removed (called a partial meniscectomy).

Most improvement was present around four months after the operation and lasted at least two years. Nearly 80 percent of the people reported “excellent” or “good” results at that time. Significantly, favorable results worsened to 65 percent by the end of the study.

The rest of the people in the study reported “poor” outcomes. In these cases, there was a major increase in pain and swelling and difficulty climbing stairs. Despite normal knees on examination, most of these patients described feelings of instability or unsteadiness in the operated knee.

Slightly more than half of the patients were able to return to pre-injury activity levels. The authors considered this a “good” result. However, the results could not be considered excellent because the other half didn’t return to normal.

Over time, X-rays showed wear and tear at the joint for all knees with partial removal of the lateral meniscus. Interestingly, pain or problems weren’t always present with this type of joint decline. Pain, swelling, knee locking, and difficulty with stair climbing were more common in older adults and those who were overweight. However, these results weren’t accompanied by changes in the joint in early X-rays.

What do doctors make of these findings? Every torn meniscus should be saved whenever possible instead of being removed. Progressive joint deterioration is inevitable when part of the lateral meniscus is taken out. Although two-thirds of all cases have positive outcomes with partial meniscal removal, one-third does not. Eventually, almost everyone has changes in the joint as seen on X-rays.

The authors questioned whether a torn meniscus be should always be surgically treated. Maybe a torn but unrepaired lateral meniscus will have the same long-term result as a “naturally aged” knee. Stay tuned!

Getting your newly replaced knee joint moving may be easier said than done. Sometimes the knee just stiffens up, frustrating both the patient and provider. It helps to know why the joint is stiff–and what can be done about it. Is it something the patient did, or did something happen during or after surgery to make the knee stiff?

Patients themselves may have something to do with it. But these factors are not always in their control. For example, some people naturally form extra scar tissue after an injury or surgery. When this occurs following knee joint replacement, the added scar tissue can cause the knee to become stiff. And a tight knee that isn’t moving fully before surgery will have a greater chance of being stiff with limited movement afterward.

Patients can control how readily they do their exercises and therapy after surgery. If they choose not to comply, their chances of having stiff knees are greater.

Loosen up. Not all problems with stiffness are due to patient factors. Errors in the way the surgery is done can also bear on stiffness in the new knee joint. An improper alignment in the parts of the new prosthesis can lead to tightness in the hinge-action of the joint. If bone spurs aren’t removed and the joint capsule is too tight in the back of the knee, tightness may occur after surgery. Likewise, an imbalance in the knee ligaments, if left untreated during surgery, can also contribute to tightness.

What about problems after surgery? Complications like infection, severe pain, or a broken or loosened prosthesis can affect knee stiffness.

Knowing when the tightness began can sometimes alert the surgeon as to the possible causes of stiffness. If the knee is stiff right after surgery, it could be from technical errors during surgery, but it could also be due to swelling and pain in the joint. If stiffness happens weeks after surgery, doctors may suspect either infection or problems with the prosthesis (loose or broken parts).

Getting the tight knee moving involves a combination of appropriate pain medication and heavy stretching in physical therapy. If the knee is still tight, patients may have to wear a special splint that helps stretch the knee. Only then does the physician recommend manipulating under anesthesia, a procedure done by forcefully stretching the knee while the patient is asleep from anesthesia.

When these efforts are unsuccessful, additional surgery may be needed. Choices include using an arthroscope to go in and remove scar tissue followed by forceful stretching of the knee. Less commonly, surgeons may need to revise or replace the parts of the prosthesis.

This author thinks prevention is the best way to avoid a stiff joint after total knee replacement. Prevention includes educating patients before surgery, avoiding technical errors during surgery, and starting a comprehensive rehabilitation program after surgery.

Over 200,000 knee replacements are done every year in the United States. People receiving new knee joints average 68 years old. A potential problem after this operation is weakness of the thigh muscles (called the quadriceps femoris). This weakness often persists even with exercise.

Loss of strength before surgery is usually caused by aging and arthritis. And if these don’t spell trouble, the operation itself affects the muscles even more. Leg weakness can keep a person from getting back to daily activities such as walking, climbing stairs, standing up from a low chair, or getting in and out of a car.

Exercise is used to build up the muscle after knee surgery, but there is often less strength compared to the other leg. In the case of one 66-year-old man, electrical stimulation was combined with exercise to increase the force of the quadriceps muscles. Electrical stimulation (ES) is used most often by a physical therapist to retrain and build up muscles. ES works by sending an electric current through a small patch, called an electrode, that’s placed on the skin over the muscle. This is a safe and pain-free way to help the muscle use more fibers and with greater force.

Three weeks after the knee replacement, this gentleman began doing physical therapy. He attended 11 sessions that included ES, stretching exercises, and strengthening exercises with weights. By measuring his muscle strength before and after this program, the physical therapist showed that the leg with the knee replacement was almost as strong (93 percent) as the other leg.

ES is a safe and effective way to strengthen the quadriceps muscles after total knee surgery. The strength gained is more than would happen from simply doing exercises. Using ES along with an exercise program can help older adults get back to regular activities sooner than normal after total knee replacement.

Whether or not patients get medical treatment has a lot to do with how they think treatment will help them, physically and otherwise. Patients’ expectations of treatment also play a part in how satisfied they are with the results.

Say, for example, a patient expects to run a marathon after anterior cruciate ligament (ACL) surgery. If the patient can’t run the marathon, he or she may feel let down by the surgery. But if the doctor knows the patient’s expectation ahead of time, he or she can address it before surgery. It may be that the patient’s goals can’t be met by the treatment. In this case, the doctor can talk with the patient about other options.

These authors wanted to find a way to measure patients’ expectations of knee surgery. The authors interviewed 377 patients about what they expected from knee surgery. Patients’ expectations included improved pain and walking. Patients also expected to be better able to do sports and daily activities. They had some expectations that surprised the authors, such as better emotional well-being.

The authors turned these expectations into questions, to use as a survey. Patients’ expectations were different depending on the type of surgery they were about to have. So the authors created two surveys. One was for patients having knee replacement surgery. The other was for patients having general knee surgeries, such as ACL surgery. The surveys were tested on a group of 163 patients. Any questions that weren’t reliable were taken out.

There were 52 categories of expectations. Return to sports was a common expectation across the board. Patients having general knee procedures expected to return to “high demand” sports such as basketball and soccer. Seven percent of these patients expected to return to professional sports.

Almost a third of patients who were having general procedures thought the knee would “go back to the way it was.” Many of these patients had had specific injuries; they hoped surgery would undo the damage.

Patients had different expectations of knee surgery based on sex, age, and education. Compared to men, women were more likely to expect walking to improve from surgery. Meanwhile, men expected to do better in sports.

Younger patients were more likely to expect better sports performance. Younger patients also thought the knee would go back to the way it was. In comparison, older patients expected less pain and an easier time walking.

Patients with less education thought they’d get pain relief and emotional well-being from surgery. Patients with more education expected to do better in sports.

Patients’ expectations also depended on how much they were able to use their knees before surgery. Patients with poor knee function thought surgery would help their walking and emotional well-being. They also expected to go back to work. Meanwhile, patients with better knee function expected to improve in sports.

The authors feel that the surveys developed in this study are reliable and easy to use. They hope doctors will use the surveys to learn more about patients’ expectations of knee surgery. By knowing patients’ expectations, doctors can give more focused care. They can help patients understand which expectations may be met by a particular treatment. This may help patients make more informed decisions about treatment and feel better about their results.

If you’re up on knee news, you probably hear a lot about tears to the anterior cruciate ligament (ACL). News about the posterior cruciate ligament (PCL) lags behind. PCL tears are less common and more difficult to treat. Some PCL tears may even go unnoticed because they don’t always produce symptoms.

PCL tears may be more common than previously thought. Researchers estimate that PCL injuries may make up 20 percent or more of all knee injuries. One researcher insists that PCL tears may account for as many as half of all knee injuries.

The PCL crosses behind the ACL. It is actually made up of two bands. These two bands work together to stabilize the knee when the lower leg moves backward or rotates outward.

PCL injuries happen when a force strikes the front of the bent knee. This can happen in a car accident when the knee hits the dashboard on impact. It can also happen in contact sports like football or wrestling. When the lower leg is struck by an opponent, the force can drive the shin backward, tearing the PCL. The PCL can also be torn when a player falls hard onto a flexed knee.

PCL injuries usually have fairly mild symptoms. Patients may have very little pain. And knee movement may be nearly the same as that of the uninjured knee. So it’s important that doctors do a thorough physical exam.

Most PCL tears can be treated without surgery. If the tear is not very serious, doctors typically recommend wearing a splint and using crutches for a short period of time. Thigh strengthening and range of movement exercises should follow. Recovery of strength and movement usually happens quickly. Patients may be able to return to sports as soon as four weeks after injury.

Studies have shown that this treatment (immobilization plus physical therapy) has good to excellent results for most patients. Patients can generally return to sports and other activities without limitation. However, in the case of more serious or chronic tears, surgery may be necessary. Surgery for the PCL is also called for if other knee ligaments are injured. In these cases, the PCL and other ligaments are surgically treated.

Typically, surgeons have used a “single tunnel” technique, in which they repair one of the bands of the PCL using grafts from the Achilles tendon. Newer “double tunnel” techniques allow surgeons to fix both bands of the PCL, which is believed to improve results. Another new procedure called “tibial inlay” involves entering the PCL through the back of the knee, to make the PCL easier to access. These newer techniques may be a step up from older methods. However, more research is needed to know which method consistently gives the best results.

Taking out part of the knee meniscus is a fairly common procedure.  Even in patients up to age 65, this procedure has good results 65 to 96 percent of the time. However, it has not been studied in patients over 70. Researchers think that age-related changes, such as the degeneration of the knee joint and cartilage, may make good results harder to come by for this group.

These authors studied the results of “partial meniscectomy” in patients over 70. Ninety-one patients had the procedure. The surgery was done with an arthroscope–a device that lets doctors operate inside the joint through a small incision.

The participants included 56 women and 35 men. Their average age was 74. Before surgery, patients had X-rays to look for signs of arthritis. Videotapes were also taken to check for damage in the articular cartilage. Articular cartilage covers the ends of the knee bones and allows the joint to smoothly bend back and forth. The results of the X-rays and videotapes were “graded” from zero to four, with zero being no arthritis or cartilage damage.

Patients whose grades were higher for arthritis and cartilage damage were generally less satisfied with surgery and were less likely to say they’d choose the procedure again. They were also more likely to need more surgery.

It is possible to get good results in patients over 70. However, the authors think that the results of meniscectomy may have more to do with the condition of the knee joint and cartilage than with patients’ age. Still, patients over 70 shouldn’t expect the excellent results typically seen in younger patients.

Knee cartilage is very durable. It’s strong enough to handle the repeated impact of running and jumping. But if you injure the ligaments in your knee, such as the ACL, your cartilage may become damaged as well. The injured ligament isn’t able to hold the joint steady. Looseness in the knee may result in degenerative changes over time. Degeneration can cause defects (lesions) in the cartilage.

How can knee cartilage be repaired? Unfortunately, cartilage isn’t vascular, meaning it doesn’t get a lot of the blood and nutrients that help the body to heal. Doctors have tried to get cartilage to repair itself by drilling small holes into the bone just below it. They’ve also tried “roughing up” the tissue to stimulate healing. Recently, surgeons have begun replanting loose bits of cartilage in the knee. Results of these methods have been disappointing. Unless cartilage transplants are attached to bone, the tissue simply dies.

These authors tried taking tissue from elsewhere in the knee to plug up the lesions. The plugs were part cartilage, part bone. Ten patients with an average age of 40 had this procedure. They got one to three plugs each. The transplants were done arthroscopically through small incisions in the skin. An arthroscope is a small TV camera that allows doctors to see and work inside joints.

Up to a year after surgery, the transplants were alive and well. The plugs healed to surrounding cartilage. They looked and felt like normal cartilage. The areas where the cartilage had been taken out for transplant healed as well. There were no complications from surgery. Though this technique is still fairly new, the authors think it may be a good option for treating some kinds of cartilage defects.

If you are a sports fan, you have probably heard of an athlete who has torn the anterior cruciate ligament (ACL). Maybe you’ve had the same injury.

The ACL is one of two ligaments that crisscross inside the knee to hold the two bones of the leg together. There are two common ways to tear or rupture the ACL. One is to keep the foot planted on the ground and twist the body over the leg. Another is getting tackled or hit from the side with a great force against the knee.

A knee injury can cause only the ACL to rupture, but often there are other injuries, too. It is not uncommon to tear the ACL and damage other knee ligaments or even tear the meniscus (knee cartilage). The torn ligaments are often repaired with an operation, but a torn meniscus can’t always be repaired. Sometimes part or all of the meniscus has to be removed. However, without this pad of cartilage to protect the joint, the knee suffers extra wear and tear. This can lead to joint damage years later.

Doctors have tested the results of surgery to repair the ACL. Two groups of people were included in a study. One group of patients tore only their ACLs. The second group had patients with ACL tears plus other knee damage. The doctors used pain, swelling, and “give way” to guide their results. (“Give way” describes a sudden moment when the knee feels unsteady, like it’s going to give out.)

There appeared to be no differences between these two groups five to 10 years after the operation. By looking at the joint, measuring joint motion, and using X-rays, doctors showed that both groups had good results.

Some members of the group with more damage ended up needing additional knee surgery, and they tended to have more reinjuries than the group with just ACL tears. Usually the repeated operations were needed because of problems with knee motion. This was most likely to happen during the time of early recovery and rehabilitation.

By continuing to look back at results of surgery, doctors can learn what works in the long term. This information can help guide future treatment methods.

In the sports world, knee injuries are a common problem, especially torn anterior cruciate ligaments (ACLs). The ACL crisscrosses with another ligament inside the knee. These two ligaments hold the two major bones of the leg together. If either one of these ligaments gets torn, the knee can become unstable. An unstable knee joint can cause the leg to feel unsteady or possibly give out. In such cases, walking can be difficult, and playing sports may be impossible.

Doctors can repair the ligament by replacing it with a piece of similar tissue taken from another part of the leg. The place where the replacement tissue comes from is called the “donor site.” Several donor sites have been used to repair the ACL, including the patellar tendon, quadriceps tendon, hamstring tendon, or the iliotibial band. Patellar and quadriceps tendon tissue comes from the front of the knee. Hamstring tendon is taken from the back of the knee. Iliotibial tissue comes from the outside of the knee. 

When doctors use more than one method to repair a single injury, it is important to keep track of which way works best. Researchers can report successful trends by reviewing all the reports available. In the case of ACL repair, doctors want to know: Which donor site holds up the best? Which donor site has the fewest problems years later?

After looking over many medical studies of ACL repairs, researchers noticed the following:

• Problems at the donor site and knee pain are the two biggest problems after ACL surgery, no matter where the donor tissue comes from.


• Small nerves can be injured during surgery, causing pain or loss of sensation at the donor site.


• There aren’t enough reports to compare all four kinds of donor-site grafts. Comparing just hamstring grafts to patellar tendon grafts shows fewer problems when the hamstring tendon is the donor tissue.


• No matter where the graft tissue comes from, it is important to get full knee motion and normal strength back in order to avoid future knee problems.


• Using patellar tendon grafts from the front of the knee results in difficulty kneeling about half of the time.

When taking tissue from different places to repair a torn ACL, doctors look at short- and long-term problems that occur at the donor site. They also examine the knee after surgery and compare motion, strength, and return to activities as measures of success. More information is needed before the overall best method for repairing the torn ACL can be decided.

Have you ever stood up to leave a movie theater and had a loud pop and pain in your knee? This is called the “movie sign.” It happens when the knee has been bent and is suddenly straightened. For some people, this can happen anytime the knee has been flexed for 15 minutes or more.

The movie sign is common with a condition called patellofemoral pain syndrome. This is a medical term for “pain and symptoms around or behind the kneecap.” It happens most often in young adults. The exact cause is unknown, but doctors think it occurs because of the position of the kneecap, or patella.

Normally, the patella moves up and down as the leg straightens and bends. There is an actual track the patella follows as it goes through these motions. Muscles, ligaments, and bone alignment help hold the patella in the middle. Many different problems can cause the patella to get off center, a situation called patellofemoral malalignment. When this happens, patellofemoral pain syndrome can develop. This includes pain, aches, and crunching sounds or “crepitus” when the knee is bent or straightened.

Some of the causes of patellofemoral malalignment include changes in normal knee anatomy, poor function of the surrounding muscles, and tightness in the ligaments that connect to the patella. Sometimes there is weakness or imbalance in the large muscle over the front of the thigh (quadriceps muscle). This muscle is made up of four parts with two major sections: the vastus medialis and the vastus lateralis. When the lateralis (on the outside of the thigh) is stronger than the medialis (the inner part of the front thigh), the patella gets pulled to the outside.

Many studies have tried to find a way to strengthen the weaker medialis muscle. No single method has been found effective. One group of researchers compared doing standard exercises for this condition versus doing exercises plus biofeedback training. They were trying to improve the balance between the lateralis and medialis muscles.

Biofeedback is a way to help patients get better awareness of muscle contractions. It can also help increase the strength of muscle contractions. In this study, electromyographic biofeedback was used. Patches or electrodes were placed on the skin over the quadriceps muscle. These recorded how well the muscle was working. Patients could hear a signal and see the pattern on a computer screen. This showed them how and when the muscle was firing.

Patients used this type of biofeedback to concentrate on getting a maximum muscle contraction. They were told to contract the medialis muscle and hold it for 10 seconds while attempting to quiet the lateralis. Unfortunately, in this study, the biofeedback treatment did not produce better results than exercises alone. Although the medialis showed improved strength with the biofeedback, there was no change in knee function or patellar tracking.

Biofeedback treatment for patellofemoral pain syndrome does not seem to be any better than the standard exercises used for this condition. The added cost and time of biofeedback can be eliminated in the treatment program. Even though this study did not have a positive outcome, researchers can still use the information. Knowing what doesn’t help can be as useful as finding out what does help.

Have you ever bent your finger back too far? Ouch! What about dislocating your kneecap? Double ouch! For some people, a dislocating kneecap, or patella, can be a problem. Sometimes the kneecap isn’t positioned over the knee joint where it should be. When this happens, the patella can get pulled too far to the outside of the knee, causing it to dislocate.

What can be done about this problem? Most people with this condition do well with a program of specific exercises to strengthen the muscles around the knee. This helps hold the patella in its proper place when bending and straightening the leg. Sometimes a soft brace or similar support helps keep the patella in the right place. When the patella dislocates over and over, surgery may be needed to correct the problem.

Realigning the patella can be done as an outpatient procedure. The patient has the surgery and goes home on the same day. The surgeon uses an arthroscope to see inside the knee joint. This instrument has a TV camera on the end that allows the doctor to repair the problem without cutting the knee open. In fact, the entire repair can be made without large incisions. It merely requires a tiny opening, about the size of a pencil eraser, to insert the arthroscope.

When an arthroscope was used for this problem in the past, it was still necessary to cut a large opening in the leg on the inside edge of the knee. That way, the surgeon could stitch the patella in place. A new technique has been devised to eliminate this step. One doctor has described how to use the arthroscope to make the repairs and realign the patella without any big incisions.

Making all the repairs on the inside without big incisions into the knee means fewer complications. The thigh muscle is not cut, reducing scar tissue and joint stiffness. In a study of 26 patients (29 knees), there were no complications and no more patellar dislocations using this method. This kind of “closed” arthroscopic patella surgery may offer doctors an improved way to repair patellar dislocations.

Injuries to the anterior cruciate ligament (ACL) can be treated either with or without surgery. Although some patients do well without surgery, most patients benefit most with surgery.

Patients seem to get good short-term results from ACL surgery. Few studies have looked at the results five or more years down the line. This study zeroed in on the mid-term results of ACL surgery in patients who showed no damage in their knee meniscus. The meniscus is a protective pad between the thighbone (femur) and the shinbone (tibia). It is sometimes referred to as “knee cartilage.”

Doctors performed this surgery using tissue from a hamstring muscle called the semitendinosis muscle. A strand of tendon from this muscle was folded twice (quadrupled) to form a strong replacement for the injured ACL.

Twenty patients were examined five to seven years after surgery. Most of the patients were male. Their average age at the time of surgery was 31. About half of them had surgery within two months of initial injury. The other half had been having knee problems for a longer period of time.

Overall, the authors were impressed with the results. An average of six years after surgery, patients’ ability to bend and straighten their knees was normal. A few patients had some limitations in movement, but these were slight.

Six patients said they still had some knee pain at follow-up: three during daily activities and three during sports. About half of the patients had kept up their normal activities after surgery. The other half was slightly less active. This change had more to do with patients’ work and lifestyle than with their knees.

The authors feel that ACL surgery using a quadrupled semitendinosis tendon has excellent mid-term results. Almost all of the patients had “normal” or “nearly normal” knees at follow-up. Patients seldom needed more surgery. And degeneration of the knee after surgery was rare. The authors recommend early treatment for ACL tears, before the meniscus becomes injured and needs to be removed.

If you have pain in your knee, your doctor may suggest arthroscopy to find the problem. Arthroscopy is a surgical procedure that uses a special TV camera to see inside the joint. Arthroscopy of the knee has been shown to be highly safe and reliable, with few complications. It is also one of the most common orthopedic procedures done today.

About 25 percent of all knee arthroscopies come out “normal,” meaning no abnormalities are found. Because of this, some doctors have asked whether arthroscopy may in some cases be unnecessary or overdone. The authors of this study identified 42 patients (44 knees) who had “normal” knee arthroscopies. The authors contacted these patients about three and a half years later, to find out how they were doing.

On average, the patients were 26 years old when they had knee arthroscopy. Three-quarters of them were men. At the time of the procedure, pain was their biggest symptom, followed by knee tenderness. Half of them had a history of knee injury.

A few years after arthroscopy, 64 percent of these patients felt better. Only 2 percent thought they were worse. Sixty-eight percent of patients had less pain, swelling, and knee locking and giving way than they had at the time of the procedure.

What accounts for these improvements? The authors think there could be a placebo effect–a kind of relief that is not due to the specific treatment used. Once patients knew there were no abnormalities, perhaps they simply learned to live with the symptoms. Or there might have been some benefit from the procedure itself.

Some doctors think that MRI scans should be done before knee arthroscopy. An MRI is less invasive and might reduce unnecessary arthroscopies. However, the waiting period for MRIs tends to be longer. And MRIs can be less accurate and more costly. For these reasons, the authors recommend continued use of knee arthroscopy, suggesting that “a negative arthroscopy is not necessarily an adverse result.” Even when there are no results, the procedure seems to offer benefits for some patients.

For many years, the meniscus, commonly thought of as the knee cartilage, was treated as though it wasn’t that important. If the meniscus tore, doctors would simply take it out. But this procedure–called meniscectomy–can have disappointing results.

The menisci act as shock absorbers in the knee, forming a gasket between the shinbone and the thighbone. It is now known that taking the meniscus out leaves the knee joint unprotected and prone to arthritis.

Thus, researchers have been exploring meniscal transplants as a possible solution after a torn meniscus has been removed. In this surgery, doctors use the meniscus from a cadaver knee (allograft) to replace a patient’s meniscus. The short-term results have been fair. These authors report on mid-term results for meniscal transplants after total meniscectomies.

In this study, meniscal transplants were done on 23 patients who had knee pain after meniscectomies. The day after the transplant, patients did leg exercises and started to move around. They returned to their normal activities six to nine months later. They were told not to do aggressive sports or distance running after the transplant.

Eighteen patients with 22 transplants were contacted an average of five years after surgery. Eleven of the patients were men; seven were women. Their average age at the time of transplant was 30. The average time between the meniscectomy and transplant surgeries was eight years. Half of the patients also had ACL reconstruction at the same time as the transplant.

Eight of the transplants (36 percent) tore after surgery. The average time to tear was two and a half years. Most happened because of some sort of trauma. The torn menisci were then fully or partially removed. Pleased with how their knee felt after the transplantation surgery, two patients who had torn the allograft asked to have the procedure again.

In general, though, patients did better after having their menisci replaced. According to questionnaires, their pain improved dramatically after surgery, as did their physical and social functioning. This was even true for those requiring another surgery to fix a torn transplant. Even with these improvements, however, most patients still showed some problems in their overall function at follow-up.

The authors were pleased to find that the outer edge of the transplants healed completely to the nearby tissues. Notably, however, the number of cells was lower in the transplanted tissue than in patients’ natural menisci. Also, the cells in the transplants didn’t function as well and produced fewer nutrients. This may explain why transplants were prone to tears.

The authors conclude that meniscal transplants can reduce pain and improve patient functioning. X-rays showed that this procedure helps prevent wear and tear on the joint. However, studies are needed to see the long-term benefits of this type of transplant surgery.