News Category: Knee

Some studies show that being overweight is linked to a poor result after total knee replacement (TKR). Other studies don’t support this finding. This study was done to compare the results of TKR in obese patients with TKRs in patients who were not obese.

Patients were matched by weight, age, and whether they had one or both knees replaced. The researchers couldn’t match patients by gender because there were many more obese women compared to men. All patients got the same kind of joint implant. The implant has been successful in use with the general population. Everyone was followed for at least five years.

The researchers looked at patients’ pain and activity levels, problems after the operation, and X- ray findings. The authors report a big difference between the two groups. There were more failures in the obese group. A failed TKR means that the patient either had to be operated on again, or had a very poor result in terms of pain and activity.

Of the group who was not obese, 99 percent had a good result. Only 88 percent of the obese group had a positive result. X-ray results were the same between the two groups. The authors conclude that the more obese the person, the greater the chances for a failed TKR. Patients in the obese group reported lower satisfaction levels, too.

The purpose of this study was to look at the effects of a custom shoe insert (called an orthotic) on knee pain. More specifically, the use of a foot orthotic for kneecap pain was evaluated. Knee pain, stiffness, and physical function were used to measure the success of the orthotic.

The idea behind using a foot orthotic is that it helps support the foot in the middle. The arch of the foot is kept from dropping down into a flat-footed position called pronation. Too much pronation can cause rotation inward of the lower leg bone (the tibia). This rotation pushes the kneecap off-center. Knee pain may develop when the kneecap doesn’t track up and down properly.

Sixteen people between the ages of 14 and 50 were part of the study. All had at least two months of knee pain and too much forefoot pronation. Everyone filled out a special form called the WOMAC. This is a group of 24 questions answered by each patient about their symptoms and function. Results of the WOMAC help decide if the orthotic is working.

Each patient was fitted with an orthotic made just for him or her. The insert was heated and molded to the foot to hold the rearfoot in a midline position. Two weeks after getting the foot orthotic, each patient filled out the WOMAC again. The WOMAC was completed a third time three months after they began using the orthotic.

The authors report that all WOMAC scores were much better after three months of using the orthotic. They conclude that custom-made foot orthoses can help patients with kneecap pain when there’s too much foot pronation. Pain, stiffness, and physical function were all improved with this treatment.

If you’ve had a knee injury you may not have full motion. Can you increase overall muscle strength when only exercising in your available range of motion? This is the question physical therapists from Israel and the United States studied together at Boston University.

The results show that strength gains made inside a small range of motion can be transferred. This means overall strength is gained when the knee is only moved within a small arc of motion. As the researchers expected, the greatest gain took place within the training motion.

But they also found that everyone got stronger throughout the full range of motion. It didn’t matter what kind of exercise they did, or how fast they did the exercises. The authors conclude that strength training can begin before patients get back full range of motion after a knee injury or knee surgery.

These findings will help therapists plan exercise programs after knee injuries or after surgery to repair torn ligaments.

Magnetic resonance imaging (MRI) is a good diagnostic tool, but a well-trained doctor is just as good. This is the conclusion of a study from the Section of Sports Medicine at the University of Kentucky. Fifty patients with knee problems were studied. The doctor’s exam was compared to an MRI for each patient. All patients had either a tear of the meniscus or a torn anterior cruciate ligament (ACL).

The authors report no difference in diagnosis of meniscal or ACL tears when using the doctor’s exam compared to an MRI. Both methods gave equal results. There were cases of false positives and false negatives with both methods. A false positive results means the MRI or exam showed a problem, but nothing was found during the operation. A false negative occurs when the MRI or exam doesn’t show a problem and there really is a torn cartilage or ligament.

MRIs have become the “gold standard” of diagnosis for knee injuries. Some doctors have called this into question. They say MRIs are high in cost, and a doctor’s exam is just as good. This study supports the use of MRI in difficult cases. But the authors conclude the MRI isn’t needed for every case.

Women are more likely to have osteoarthritis (OA) of the knee than men. Overweight women have worse results after knee surgery than women of normal weight. These are the results of a study comparing women between the ages of 30 and 55 who had arthroscopic surgery on the knee.The operation was done to repair or remove torn cartilage and smooth the joint surfaces. The authors say this is the first study to show a link between body weight and results of arthroscopic surgery for OA.

Each woman was asked a series of questions four to 11 years after the operation. The questions covered physical function, mental health, and satisfaction. Answers were compared between two groups. One group of women was overweight at the time of the operation. The second group was the same age and had the same operation. However, the women in the second group were normal weight.

All patients reported getting better after the surgery. Obese women had more trouble with physical activities such as walking or climbing stairs. They also reported more problems with work and daily activities. These problems may be caused by a condition called chondromalacia. Chondromalacia occurs when cartilage behind the kneecap is rough or damaged. The result is more knee pain.

The researchers conclude that arthroscopy works better for patients with mild degenerative problems. Patients who are overweight and who have OA may not do as well after arthroscopic surgery.

Heart disease is the number one killer of women over age 50 in the United States today. But pain from knee osteoarthritis (OA) is the number one cause of disability among this same group. And the number of women affected by OA is expected to rise in the next 10 years.

A physical therapist at the University of Kentucky focused on this topic in a recent study. Two questions were asked: How much does the severity of OA affect pain, balance, and self-efficacy? How much do pain, balance, and self-efficacy affect function?

Self-efficacy is a person’s belief that he or she can or can’t do a task or activity. Research shows that self-efficacy is linked to whether or not a person will try new things. The amount and length of effort put in are also related to self- efficacy.

Fifty women over age 50 with knee OA were included in this study. A special scale called the WOMAC scale (Western Ontario and McMaster Universities Osteoarthritis Index) was used to measure pain and function. The author found that balance was linked to function. The better the person’s balance, the more improved his or her physical function.

The same was true of self-efficacy. As the person’s self-efficacy increased, physical performance got better. But pain got in the way of self-efficacy. Even if a patient thought she could do an activity, pain levels could keep her from succeeding.

The findings of this study suggest that patients can get greater control over their pain and function. One way to do this is through education. Patients need to know more about OA and what to expect. Learning may increase self-efficacy, which in turn, helps people face their challenges.

Studies show muscle weakness after total knee replacement (TKR) is common months and even years after the surgery. This study compares the force produced during a single-leg press after TKR. Nine patients with TKR were compared to nine adults without TKR (the control group).

This is the first study to measure force produced by the leg after TKR in a weight-bearing position. It’s unique because force is examined across several joints using many muscle groups. This gives a better idea of what’s going on in a fully weight-bearing position. Other studies have reported on forces in one joint at a time. Often only the knee extensor muscles are tested.

The authors report that there is much less force through the leg with the joint replacement. These measures were lower when compared to the patient’s healthy leg and when compared to the control group. This shows that the entire leg, not just one set of muscles, has less power.

The researchers suggest that the loss of force in the leg with the TKR may be present even before the joint replacement. Pain from arthritis causes the patient to favor that leg. Gradual weakness occurs as a long-term effect of the arthritis.

Weakness before and after surgery will be the focus of the next study. The goal is to find out which exercises are needed before and after TKR to restore full force to the leg.

When the anterior cruciate ligament (ACL) is damaged, the quadriceps muscle may go haywire too. The quadriceps muscle along the front of the thigh helps straighten the knee. It can become weak and out of sorts when the ACL is injured. The change in muscle activity and resulting problems with coordination are called dyskinesia.

Physical therapists at the University of Delaware teamed up with engineers to study this problem. They hope to find better ways to restore total knee function after ACL injury. In this study two groups of 15 subjects each were tested. Group one had ACL problems. Group two had uninjured or “normal” knees.

Two types of knee motion were studied: static (joint doesn’t move) and dynamic (joint moves). Nerve tests were used to measure the activity patterns of the muscles around the knee. The authors report major differences between the two groups. The subjects with ACL injuries had less control of the quadriceps muscle in both types of motion.

The biggest finding was that the quadriceps muscle didn’t “turn off” in the injured group. During movements when the quadriceps should be relaxed and calm, it was active. This change in the muscle activity pattern was most noticeable for the vastus lateralis (VL). The VL forms the outside (lateral) portion of the quadriceps muscle.

The authors conclude that without a “cease fire” order, the quadriceps can’t control knee motion properly. This may explain why the knee is unstable and gives out on some people with weak ACLs. Therapists aren’t sure why the muscle fibers don’t stop contracting. Further studies are needed to get to the bottom of this mystery.

Is repairing a torn meniscus better than just removing it? Doctors at the Shelbourne Clinic in Indianapolis reviewed 91 cases treated between 1982 and 1995 to find out. They were looking for the best treatment for an unstable bucket-handle meniscal tear.

A bucket-handle tear is the most common injury to the meniscus. The cartilage tears in a crescent-moon shape, like a bucket handle. The inner part of the cartilage often dislocates. It shifts into the notch where the knee ligaments cross each other.

This type of tear used to be treated by taking the entire meniscus out. But studies show that damage to the knee joint can occur when the meniscus is gone. Finding a way to repair rather than remove the cartilage is the new focus of research.

This study only included patients with a tear on the lateral side (outer edge) of the meniscus. The lateral meniscus isn’t attached as tightly as the medial (inner) meniscus. This means it moves and shifts easier during joint motion. The lateral meniscus is also larger than the medial meniscus. These factors make tear patterns and healing different for lateral meniscus tears.

In this group all 91 patients had a torn anterior cruciate ligament (ACL) and a torn lateral meniscus. All ACLs were repaired. Of all the patients, 67 had the meniscus repaired, while 24 had the meniscus removed. Everyone had the same rehab program after the operation.

Results showed no difference between the two groups in swelling, stability, or activity level. The group who had the meniscus removed had more pain than the repair group. The authors think this difference may be an early sign of joint damage. X-rays won’t show any changes until years later.

In this report, well-known surgeons in sports medicine present results of a study on knee meniscus transplants. A step-by-step description is given for several meniscal repair operations. Possible problems and pitfalls are mentioned.

Special instructions are given for meniscal transplant on the inside or outside edge of the knee joint. The authors include how surgeons test the patient’s knee while still in the operating room.

Results of the study are detailed and cover a wide range of measures. For example, some results are given based on the condition of each patient’s knee (mild to severe changes). The patient’s level of activity is reviewed before and after the operation. X-ray findings and MRI results are described before and after the operation. Problems after surgery are also discussed.

All 40 patients in this study were less than 50 years old. All had a meniscal transplant. About 40 percent of the patients had a second operation at the same time. This second operation was a bone transfer called osteochondral autograft transfer. It’s used when the meniscus is damaged so badly that the bone underneath is showing.

The authors say this is the first report about the outcomes of these two operations together. Success and failure rates are reported. Eleven of the 40 total transplants failed. This is about 30 percent of the total group.

The authors conclude that meniscal transplants often tear or fall apart after being put into the knee joint. It’s still a good option for young patients with severe joint damage and no other choices. Treatment is advised as early as possible before more joint damage occurs.

Many studies have looked at the effect of hormones on the knee in women. Changes in knee ligaments have been found during the menstrual cycle and during pregnancy. This is the first report on knee laxity as measured throughout the monthly menstrual cycle.

Twenty-five nonathletic women between the ages of 18 and 30 took part in this study. Knee joint laxity and hormone levels were measured daily for one complete menstrual cycle. Joint laxity refers to how loose a joint is, or how much one side of the knee joint slides against the other. Estrogen, progesterone, and testosterone were included in the hormone measures.

The authors of this study expected to find changes in knee laxity after a rise in hormone levels. They thought estrogen and progesterone together would make a bigger difference than either one alone.

What they actually found was that each hormone affected knee joint laxity. This occurs across the monthly cycle. There was a time delay of three to four days. The effect was greatest when the hormones were combined.

The authors report a wide range of results among women. It’s difficult to know for sure when knee laxity will increase or decrease across the menstrual cycle. This variation makes it difficult to predict and prevent knee injuries. The authors suggest a three-month study as the next step.

Physical therapists are busy finding ways to stop anterior cruciate ligament (ACL) injuries of the knee. This study reports the results of a balance-training program. The goal was to improve balance in young female athletes as a way to prevent ACL injury.

Females in sports are more likely to injure the ACL than males. In fact, the rate of ACL injury in female athletes is six times higher than for male athletes.

Forty-one high school athletes (girls ages 13 to 17) trained for six weeks. They did balance exercises for 90 minutes three times each week. The training took place during the summer before the playing season began.

A special tilting (moving) platform was used. This device measured the girls’ postural stability before and after the program. Postural stability is the ability to stay standing upright when moved off balance. The girls were displaced by the unstable surface of the platform. They were standing on one foot for 20 seconds during the test. The platform measured how far off center the foot moved during that time.

The authors report that everyone showed improvement in single-leg stability. Participants could hold the foot level when the movement was forward and back better than when the motion was from side to side. The training seemed to help the right leg more than the left.

Many studies show how rehab helps patients recover after surgery for a torn or damaged ACL. This report adds to that bank of data by showing that as little as six weeks of training can improve postural balance in the leg. Better balance means greater stability and fewer ACL injuries.

Osteoarthritis. Proprioception. Arthroplasty. What do these have in common? They all make a difference in how the knee moves and functions. This study from the Anderson Orthopaedic Research Institute in Virginia takes a closer look.

Proprioception tells the knee where and how it’s moving. It’s the ability to sense joint position. It tells us about any changes in the position of the joint. Patients with osteoarthritis have poorer proprioception than those without arthritis. The worse the symptoms, the worse the proprioception.

But what if only half the joint needs to be replaced (called unicondylar arthroplasty)? Is proprioception better in joints with less severe arthritis?

According to this study, age is the biggest factor in proprioception, not severity of disease. Younger patients tend to respond sooner to changes in joint position. Men have a slower response time when straightening the knee compared to bending it.

Scientists don’t know if the loss of proprioception causes knee osteoarthritis (OA). Maybe it’s the other way around, and OA causes changes in joint position sense. Finding out more about proprioception may help doctors find the best treatment for patients with knee OA.

Electric garage door openers. Electric can openers. Electric toothbrushes. Now electric goniometers. A goniometer is a device to measure joint motion. Physical therapists work it by hand to measure patients’ progress. It’s used most often after injury or operation.

In this study a computerized electric goniometer was studied. It gave biofeedback to patients after total knee replacement. The patient could hear a beep or see a screen with a display of joint measurements.

The idea behind such a device is to remind patients to exercise on their own. A biofeedback unit of this type can measure motion. It can also keep track of how often the patient exercises. The electric goniometer can be set to limit motion prescribed by the doctor or therapist. Patients can monitor their own progress and exercise safely.

Results were measured in terms of motion and activity. What was the average activity during the day? Did the patient feel okay about wearing the unit? Did the electric goniometer give the same measure as a manual unit?

The researchers found no difference between the manual and machine goniometer. Pain levels were the same no matter how the motion was measured. Most patients said the unit was comfortable. They used the beep sound to guide them more than the visual display of their motion. They would use it again if they had the same surgery another time.

The authors conclude that such a device isn’t needed by everyone. But for some patients recovery may be slow. They may have severe rheumatoid arthritis, obesity, or psychological or social problems. A method of reminding them to do their exercises may be useful. More research is needed to measure how well it works and if it can save money.

Scientists sit up and take notice of research results when a study is randomized, controlled, and double-blinded. That means there are two groups of subjects. Each person is randomly placed in a group, and no one knows what group they are in. This is the first study of this type looking at the use of electrical stimulation (ES) for patellofemoral pain syndrome (pain where the kneecap meets the thighbone).

ES is used to make a muscle contract without the subject’s voluntary contraction. A new type of ES has a mixed-frequency pulse that increases both muscle endurance and power. The older, more traditional ES increases one or the other, but not both at the same time.

These two types of ES were used on 80 patients at home. Everyone had muscle stimulation one hour daily for six weeks (42 sessions). The results were compared using pain, size of muscle, and strength as measures of outcome. Knee flexion was measured by having the patients squat as far as possible before having knee pain.

The authors found no difference in results between the two ES units. Patients in both groups showed improvement in strength, function, and pain levels. Knee flexion improved equally in both groups. A small difference was seen in muscle size.

The researchers offer several possible explanations for these results. They suggest that pain may be reduced when muscle strength improves because the kneecap can track up and down better. A second explanation may be that the ES blocks pain signals by entering a different signal along the same nerve pathway.

Since the patients reported less pain several hours later, it was thought that the change occurred because of the effect of the ES on the muscles rather than from blocking nerve signals. In any case, the effects of ES were the same with both types of frequency. One wasn’t better, or worse, than the other.

Knee osteoarthritis (OA) often causes pain and loss of motion. Muscle weakness and changes in walking (gait) pattern occur. In this study, researchers report on the results of hyaluronate knee injections for OA. They look at two factors: changes in gait pattern, and loading on the joint from the ground up into the knee. This type of load is called joint ground reaction force (GRF).

Normal load through the knee joint can be altered by OA. Sometimes the load shifts to one side of the joint more than the other. This adds stress and further damages the cartilage in that part of the knee joint. Injections to restore the joint lubricating fluid may change both the gait pattern and the GRF.

Two groups of adult women were included in this study. The control group had healthy knees without any signs of OA. The second group had stage I or II OA. This group had changes in their gait patterns and GRF compared to the control group. Changes in GRF are a sign of abnormal joint loading.

The OA group received daily injections into both knees for five days. Gait pattern and GRFs improved after the injections. The changes were seen right away and lasted at least six months. The authors conclude that hyaluronate injections are a good treatment option for some patients. In general, the injections are safe, reduce pain, and sometimes improve function quickly.

There’s no clear proof that anterior cruciate ligament (ACL) reconstruction protects the knee joint from arthritis. In fact, the amount of osteoarthritis reported in knees is the same for patients who have had an ACL repair compared to those who have normal knees.

Scientists at the Henry Ford Health System in Detroit, Michigan, are looking for some answers to this puzzle. They think ACL reconstruction may not restore normal rotation in the knee. The lack of normal rotation may lead to more and more cartilage damage over time. To test this idea they studied six subjects running downhill. They used a special high-speed 3-D system to measure joint motion. The patients’ healthy knees were compared to the knees with ACL repairs.

Everyone was able to run downhill at a jogging pace. No one had pain or limped. Measurements showed forward and backward motions of the tibia (lower leg bone) on the femur (thighbone) were the same on both sides for all patients. This motion is called anterior translation. The real difference was in the outward (external) rotation and in the inward angle (adduction) of the knee. The repaired joints had more of both these motions compared to the normal knee.

The authors think these results show that restoring anterior translation doesn’t mean the joint will function normally again. This finding is surprising, since the goal of ACL reconstruction is to hold the joint stable and to prevent too much of this forward translation.

It looks like the researchers’ first theory was right. Abnormal motions other than joint translation may result in joint damage after ACL repair. This information may help surgeons improve ACL reconstruction techniques. Restoring all joint motions to normal may be the key to reducing osteoarthritis after ACL reconstruction.

Patients who get a total knee replacement (TKR) are told to come back to the doctor’s office on a regular basis for check-ups. If they don’t return, does that mean the operation failed and they are seeing someone else now? Doctors at Brigham and Women’s Hospital in Boston used the internet to find patients who didn’t come back and see what happened to them.

There were 161 patients with a total of 200 TKR surgeries. Thirty of those patients had not been in contact with the surgeon for at least six months. Seventeen patients were contacted using information from their charts. The 13 remaining “lost” patients were found using search engines on the internet.

Each patient had a TKR for at least five years. All patients were asked about their knee implants. Having any problems? Seeing another doctor? Why didn’t you come back? The researchers report that only three patients were seeing another doctor somewhere else, for convenience. The patients who weren’t followed had the same outcomes as those who did have follow-up. No one had more knee surgery after the TKR.

There were many reasons why patients didn’t go to their follow-up appointments. The two most common ones were death (unrelated to the TKR) and not knowing they needed to see their doctors. A secondary reason given by many patients was that they weren’t having any problems with their knees. Most of the patients who didn’t have follow-up care were older at the time of the surgery.

The authors say that finding problems early after a TKR can prevent further surgery. Everyone should be told how important follow-up appointments are after TKR. Patients should be seen by their doctors every one to two years. This study shows that doctors can find patients who don’t come back by using the internet. It’s free, and it doesn’t take much time to locate lost patients.

Do patients with knee pain from osteoarthritis (OA) increase the weight and load through the knee after taking pain relievers? This is the first study to try and find an answer to the question. Researchers at the University of Chicago say pain relief increases the load while walking, but not during stair climbing. They think other factors may be involved in stair climbing.

Many patients with OA end up with increased wear and tear on the inside edge of the knee. Pain causes them to limp or shift the weight to the other leg. Their walking speed slows down, and their rhythm becomes uneven.

In this study, authors compared two groups: adults with OA, and adults without OA. The study was done in a motion analysis lab. Each group walked on a walkway that can measure force from the ground up through the knee. Speed and stride length were also measured. Three trials of walking and stair climbing were done.

Then the OA group got a knee injection for pain. All patients reported pain relief. After 15 minutes, three more trials were done. The researchers found no change in forces through the knee during stair climbing. Walking did change. It was measured as equal to the group without OA.

The authors conclude that pain relief from knee injections tend to normalize walking in patients with OA. Other factors such as overall health, swelling, and muscle weakness may be why load didn’t change with stair climbing.

A torn meniscus in the knee can occur alone or along with a torn anterior cruciate ligament (ACL). Patients with just a meniscal tear have better long-term results than patients with both cartilage and ligament tears.

These are the results of a long-term study of 28 knees over an eight- to 14-year period. Results were measured on the basis of symptoms, function, and X-ray or MRI findings.

Everyone in the meniscus-only group had an excellent rating on follow-up. Four of the 20 patients with the added ACL tear showed good results. Both groups had good function. The big difference was in arthritic changes. The meniscus-only group had no arthritic changes. More than half of the ACL group had arthritic changes.

MRI images showed that the more stable ACL repairs had less severe arthritis. The authors conclude that degenerative changes after reconstructive surgery for meniscal tears can be seen on MRIs. The best way to protect the torn meniscus after repair is to make sure the ACL is also stable.