News Category: Knee

Ligaments attach bones to bones. The anterior cruciate ligament (ACL) connects the femur to the tibia. In a way, it also connects the knee to the brain, and to the hamstring muscles of the thigh.

Animal research has shown a nerve pathway that goes from the ACL to the spinal cord and back to the hamstring muscles. This is called the ACL-hamstring reflex arc. Recent studies have shown that the human ACL sends nerve signals to the spinal cord. This study was designed to test whether humans also have the ACL-hamstring reflex arc.

Researchers attached electrodes to the hamstring muscles of nine men with healthy knees. They also inserted electrodes into their ACLs. The muscle reactions were then monitored as the ACL was electrically stimulated. The hamstring muscles of all nine subjects had reflex reactions when the ACL was electrically stimulated.

The ACL was then numbed with an anesthetic, and the tests were repeated. The hamstring muscles showed no reaction after anesthesia. These results support the theory that humans also have an ACL-hamstring reflex arc.

These signals that go from the ACL to the spinal cord help keep the knee in safe alignment. This “sixth sense” is called proprioception. Our sense of proprioception alerts the body about the position of its joints and muscles. Research such as this suggests that proprioception may be one of the most important factors in knee function.

New information like this is important. It can help surgeons develop more effective ACL surgeries, and it can help therapists design better rehabilitation programs for their patients with ACL problems.

Time heals everything. Or does it? A group of orthopedists in Australia set out to discover the relationship between the passage of time after a knee injury and the extent of knee damage. The researchers looked specifically at meniscus and cartilage damage in patients after an anterior cruciate ligament (ACL) injury.

The ACL connects the thigh bone with the tibia in the lower leg. The ACL plays a key role in stabilizing the knee. Injury to the ACL has been tied to damage of the cartilage surfaces and menisci of the knee. When the ACL is injured, the knee may become unstable, putting more strain and wear on these other knee structures.

Using an arthroscope, researchers looked inside the knees of 130 patients with known ACL damage. (All subjects were scheduled for surgery to repair their damaged knee ligament.) The subjects ranged from one month to a couple of years past the initial knee injury.
Researchers found that the more time that passed since the initial injury, the greater the damage to the cartilage and meniscus. Most patients (72%) showed meniscal damage or loss, with an average of three inches of cartilage damage.

To keep these other knee structures from being damaged, the authors conclude that ACL injuries should be surgically repaired sooner rather than later. The researchers caution that these findings may not apply to all ACL injuries, since many don’t require surgery.

Damage to the cartilage and meniscus may also have something to do with how badly the knee was initially injured. And it is possible some of the subjects already had damage to these other knee structures before they injured their ACL. Still, this study shows that the passage of time can do more harm than good.

Taping the knee has become a standard method of treating pain caused by a poorly aligned kneecap (patella). The idea is that the tape helps hold the kneecap in better alignment. But does the tape actually improve the position of the kneecap? Past research is unclear.

This study involved 16 young women with alignment problems of their patella. Researchers took pictures of the bones of the subjects’ knees using computed tomography (CT). The CT scans were used to see the position of the knee caps before and after taping the knee, and with or without having the subject tighten the quadriceps muscle.

Only four knees showed even a slight improvement in patellar alignment with taping. In the rest of the knees, taping made no difference in alignment at all.

Patellar taping may indeed help ease pain or provide support for the knee cap. But the authors conclude that the benefits from taping do not seem to be from correcting the alignment of the patella.

Which sport and recreational activities are safe for someone who has had total knee replacement surgery? At best, past answers were educated guesses. At worst, a poor guess might end up causing a person to participate in activities that put too much strain on the implant, leading to extra wear or possibly even destruction of the replacement parts.

Now doctors have fresh scientific information to help them guide their patients after knee replacement surgery.  Scientists experimented with three different types of knee joint replacements. After securing each joint in a special holder, they measured the amount and location of the pressure on the joint during simulated activities of cycling, power walking, downhill walking, and jogging.

They found that stress levels from cycling and power walking were evenly spread over the surfaces of the joint. Downhill walking and jogging built up too much pressure over the joint surface. As a result, the authors determined that power walking and cycling can be permitted after total knee replacement surgery, but activities like jogging, hiking, and downhill walking place the joint at risk.

Their study showed how the pressure on the joint builds up the further the knee bends. This led the authors to recommend that people who cycle after total knee replacement surgery should raise their bicycle seat as high as comfortably possible. They also recommend doing a combination of activities, like walking and cycling, so the joint isn’t loaded the same way all the time.

“Cycling and power walking seem to be the least demanding endurance activities for the knee joint,” say the authors. “Regular jogging, or sports involving running,” they conclude, “should be discouraged after total knee replacement.”

Most of the tissues in the human body respond to the demands placed on them. For example, the weightlessness of space travel weakens soft tissues. Lifting weights improves muscle tone. Walking and other weight-bearing exercise can improve bone strength. But cartilage in the knees of triathletes doesn’t seem to get thicker from their heavy schedules of training and competition.

This was an unexpected finding in a recent study that compared the knee joint cartilage of nine triathletes and nine inactive volunteers. To be included in the study, the triathletes had to have been active throughout life and training for at least 10 hours per week over the past three years. The inactive group included people who had never done more than one hour per week of any type of sport or heavy work at any time in life.

Using magnetic resonance imaging (MRI) and three-dimensional imaging technology, the authors calculated cartilage thickness of the right knee joint of each participant. In general, the results showed wide differences in the cartilage thickness between participants. Although there were parts of the knee that tended to have slightly more cartilage in triathletes, there were some areas that had less. The conclusion drawn by the authors is that the cartilage was generally not thicker in the knee joints of triathletes. “These results are unexpected,” say the authors, “in view of the functional adaptation observed in other musculoskeletal tissues.”

Past animal studies that measured the effect of activity on cartilage have shown varied results. No other studies have been done measuring the effect of physical activity on cartilage thickness in the human knee. Even though the cartilage didn’t look thicker on MRI, the authors caution that these types of images don’t show whether the chemical makeup is different, since MRI can’t detect these kinds of changes.

A mere few years ago, most surgeons probably wouldn’t have considered doing surgery to reconstruct the anterior cruciate ligament (ACL) in patients over 40. However, with the steady rise of more technically advanced ways to do this surgery, the boundaries of age are being stretched.

But how do “older” patients fare after ACL surgery? Surely they don’t do as well as their younger counterparts. Or do they?

Fresh evidence indicates that patients over 40 have results after ACL surgery that are comparable to patients in their early 20s. Two groups of ACL patients were compared before and after surgery. One group included people over the age of 40. The other represented the typical age group for this type of surgery, ages 20 to 24.

Patients had a recheck within 38 weeks after surgery. The final results showed that the older group did nearly as well as the younger group. Researchers measured the patients’ knee motion, ability to hop on one leg, and side-to-side slackness in the affected knee. In each instance, the differences were minimal between groups.

Researchers also asked questions about daily activities and knee function. The questions showed only one major difference between the groups. Younger patients tended to return to higher activity levels after the surgery.

When asked about their opinion of the surgery, the people in the middle-aged group reported being more pleased with their results than those in the younger group.

The authors conclude that being over 40 shouldn’t be an obstacle to good results from ACL surgery. Hmmm. Too old to have an ACL surgery? That’s almost like saying you’re too old to rock ‘n roll.

Believe it or not, catching a ball can actually make you more likely to suffer a knee injury. Injuries to the anterior cruciate ligament (ACL) of the knee are more common in sports like basketball, which involve sudden stops and ball handling. Researchers in Australia tested why that may happen.

They tested seven male and 11 female recreational athletes with an average age of about 23. The subjects ran three steps and then jumped onto a force platform, where they landed on one leg. Sometimes, without advance warning, they had to catch a ball as they landed.

The subjects were filmed and their muscle activity measured as they did the jumping tests. Researchers found that catching a ball didn’t change the movements or angle of the legs, hips, or body as the subjects landed on the platform. However, catching a ball made major changes in the timing of muscle contractions. Something about catching a ball made the quadriceps contract earlier and the hamstring contract later than during the other landings.

Normally, the hamstring muscle keeps the tibia bone in the lower leg centered. This keeps it from sliding forward under the femur bone of the thigh. If the quadriceps muscle on the front of the thigh tightens without the opposing action of the hamstrings, the tibia gets pulled forward. This causes the ACL to become taut to the point where it can stretch out. It may even tear.

Proper muscle coordination when landing on one leg helps protect the ACL and the rest of the knee from heavy force. This study shows that catching a ball can alter muscle coordination between the quadriceps and hamstring muscles, making the ACL more vulnerable to injury. But why this happens is still a mystery that demands more research.

Knee pain is the most common problem facing people who run more than 10 miles per week. Most of these problems happen in the anterior(front) part of the knee, around and under the kneecap. Each year, up to 65% of all distance runners will have to stop running or seek medical care due to anterior knee pain. Since there are about 32 million regular distance runners in North America, that translates to roughly 21 million people.

Knowing which runners are at risk for knee pain is the first step toward prevention. To help with this, the authors recruited runners at local races and in running magazines. Two groups were formed. Seventy non-injured runners were selected for the control group, and 99 injured runners were selected for the injury group. All the runners completed detailed questionnaires about their running experience, training routines, running terrain, shoes, and injury history. Researchers used medical and video technology to measure each runner’s legs, feet, strength, stride, and running style.

The authors found several differences between the groups. Runners were more likely to have problems with anterior knee pain if:

• They had high arches in their feet.


• Their feet didn’t begin to pronate as soon as they hit the ground.


• They had weakness in the muscles that straighten the knee.

Professionals who work with runners may be able to use this new information to help their clients avoid problems with anterior knee pain.

Doctors and surgeons now have many ways to treat ligament injuries, with or without surgery. But there are still many questions about the way ligaments heal. To summarize what is known about ligament healing, the authors focused on two different knee ligaments, the medial collateral ligament (MCL) and anterior cruciate ligament (ACL).

Athletes commonly injure both these knee ligaments. Treatments for these ligaments can range from simple remedies like rest and ice to surgery. However, no matter what kind of treatment is used, injured ligaments may never become as good as new. Two years after an injury, electron microscope studies show that the cells in the injured area are smaller in size and shape. This verifies that the ligament still hasn’t returned to normal.

Ligament healing is affected by many factors. Most MCL injuries, for example, tend to heal better without surgery. Not so with ACL injuries. Doctors are not exactly sure why this is true. It may have to do with factors like blood flow to the ligament and the ligament’s structure. New scientific discoveries are guiding the ways doctors and other health professionals treat injured ligaments.

The authors listed several new advances that may someday be used to speed the healing process.

• Growth factors are small polypeptides that bind to cells and promote cell growth.


• Gene transfer technology involves transplanting genetically altered tissues into the ligaments to improve healing.


• Cell therapy uses genetically altered cells to enhance ligament repair.

In the past decade there have been many advances in the way surgeons repair the meniscus of the knee. New methods of surgery and new technology have helped make the surgery easier for patients and surgeons.

An absorbable implant is one type of technology that has become widely used in meniscus surgery. These biodegradable pieces can be placed through a tiny incision. A type of absorbable implant called an arrow is used to hold together healing tissues. It works sort of like a staple or a pin. The tissues heal together, and the implant slowly dissolves over a period of about three years.

These authors reported case studies of problems with arrows used in meniscus surgery. Four of 28 patients developed cysts over the arrows 10 to 12 weeks after surgery. The cysts all went away in 18 weeks by themselves. Another patient had the arrowheads break off the shaft of the arrow, causing small indentations in the cartilage on the surface of the thigh bone. The authors commented on other instances where the arrowheads had broken.

None of these patients had lasting difficulties. However, the authors suggest that more study is needed on the long-term effects of using arrows for repairing the knee meniscus. They were especially concerned that the broken arrowheads could indicate a design problem that may need to be corrected.

When the kneecap is out of whack, doctors call the condition patellar malalignment. (The patella is the kneecap.) Patellar malalignment often goes undiagnosed. The author suggests that, when it is diagnosed, doctors are sometimes too quick to use surgery as the first treatment.

There are two kinds of symptoms related to patella problems, slipping and pain. Patients who feel the patella slip, or even dislocate, usually have mechanical problems with their knee. Patellar pain, on the other hand, isn’t fully understood by doctors. Many patients with patellar malalignment don’t feel any pain. Others do. Factors such as an injury or overuse seem to trigger the pain. Other disorders may cause the pain, such as nerve or blood vessel problems or inflammation of the patellar tendon. And some conditions can cause patellar pain even when the patella is correctly lined up.

The author discusses a number of ways to identify patellar malalignment. Foot problems, tightness of the muscles around the kneecap, and pain in certain knee positions can all suggest patellar malalignment. Most cases of patellar malalignment don’t require fancy testing or surgery. The pain usually goes away with conservative treatments including ice, rest, anti-inflammatory drugs, and physical therapy. Stretching and strengthening exercises have proven helpful as a way to keep the kneecap in better alignment. Knee braces or taping the kneecap may also help center the kneecap, easing pain. In some cases, abnormal foot positions cause the problems in the knee. Orthotics to better align the feet may help in these cases.

When their patients end up needing surgery, doctors have several ways to help. Most types of surgical procedures for this problem are used to improve the alignment of the patella.

The posterolateral (back and outside) corner of the knee has been called “the dark side of the knee.” Much less is known and understood about its complex structure than about the rest of the knee joint. This author sheds some light on injuries of the posterolateral part of the knee.

Posterolateral knee injuries don’t happen often. When they do occur, they can cause severe disability. Usually they happen along with damage to the central knee ligaments. In many cases, the injured ligaments are treated, but the injury to the posterolateral structures goes undiagnosed. When this happens, surgery for the central ligaments may eventually fail.

Posterolateral knee injuries are difficult for doctors to diagnose. There may be pain in the back and outside part of the knee. Damage to nerves is fairly common, so there may also be tingling or numbness in the leg. The author lists some ways for doctors to examine the knee and suggests imaging tests that can help identify damage to this part of the knee. Arthroscopy may be necessary for accurate diagnosis. This involves inserting a tiny TV camera into the joint.

Mild or moderate tears in the outer portion of the knee may heal without surgery. Complete tears usually require surgery. Surgery is more likely to be successful when it is done soon after a severe injury. Surgery is less successful when posterolateral problems develop over a long period of time. The author concludes that future research should focus on improving ways to repair the posterolateral corner of the knee, now that we are learning more about the knee’s “dark side.”

How FAST can you decide which is a more cost-effective treatment for knee osteoarthritis? To help answer this question, researchers designed a FAST study: the Fitness and Arthritis Seniors Trial.

Information about cost-effective treatment is needed to help identify the best treatments and, ideally, to lower costs of medical care. Calculating the benefits of preventive treatment is a challenge, especially when trying to decide the monetary value of less pain, better movement, or longer life. This study measured the benefits of various types of treatment for knee osteoarthritis (OA), along with the costs for each treatment.

After screening nearly 5000 people, the authors included 439 seniors in the study. Participants were randomly placed in one of three groups. One group did only aerobic exercise. Another did only resistance exercises. The third group served as a control group and received only education. To begin, participants completed a questionnaire about their knee condition. Then they were scored in their ability to do various daily activities, such as a six-minute walk, going up and down stairs, lifting and carrying, and getting into and out of a car. They also reported their pain levels.

The aerobic and resistance exercisers did their first three months of training in the clinic. They continued doing their program at home for another 15 months. Aerobic exercisers warmed up, walked, and then did a cool down for a total of 60 minutes, three times each week. People doing resistance exercises worked their major muscle groups using nine different strengthening exercises for the upper and lower body. The control group received monthly education classes for three months, each lasting 1.5 hours. A nurse contacted each person in the education group at regular intervals over the next 18 months.

The same questionnaire, scored tests, and pain reports were completed after the test period. The findings showed that costs were slightly less for resistance training than aerobics. And both types of exercise cost less than the education format. Looking at the benefits that were gained for the amount of money spent, resistance training had a bigger effect on overall knee health compared to the other two groups.

Even though the differences were small between aerobic and resistance exercise, the authors conclude that “resistance training is more economically efficient than aerobic exercise in improving physical function, when self-reported disability and various measures of physical function are the outcome variables considered.”

New evidence shows that special hands-on treatment given by trained physical therapists helps ease pain and stiffness in patients with knee osteoarthritis. The manual treatments used by the physical therapists in this study included hands-on tissue work, graded joint movements, and stretching. These treatments have been shown to calm pain and inflammation, help joints move better, and relax muscles.

Eighty-three patients were randomly placed in either a treatment group or a control group. Both groups were given a survey about their pain. They were also tested to see how far they could walk in a six-minute period. Then the patients went to therapy two times each week for a total of four weeks.

Along with manual therapies, the patients in the treatment group also did standard knee exercises in the clinic and at home. Participants in the control group were only given mock ultrasound treatments set at the lowest possible level, too low to really help their knee problem. This group was also told not to do anything different in the way of exercise or activity.

In the first few visits, people given manual treatments reported feeling 20 to 40 percent better. All patients again took the survey and did the walking test at eight weeks and then at one year after starting the therapy. Participants in the treatment group showed significant improvements according to the survey, and they walked further during the six-minute walk test. Compared to the control group, the patients treated with manual and exercise therapies had less pain and stiffness and fewer problems with activity, even up to one year later. The authors consider that manual therapy for knee osteoarthritis might help patients avoid, or at least postpone, the need for a new knee joint.

Who says you’re too old for knee surgery to reconstruct a torn anterior cruciate ligament (ACL)? Doctors Miller and Sullivan recently reported on a rancher who had a successful surgery on his ACL. Nothing new, right? Except that the patient was 84 years old at the time of surgery.

Surgery to reconstruct a torn ACL is usually only done on younger patients. Most doctors consider 40 to be old for an ACL surgery. The authors were unaware of anyone older than 62 having this type of surgery.

According to the doctors, the patient had been trying to get along without surgery, but ranching was too much of a challenge. Walking around on the uneven ground caused his knee to give out on him. Rather than change his lifestyle, he opted for surgery.

The surgery was a success. Three months later, the patient was back to his normal activities. When he went back to the doctor for a six-month recheck, he had full knee movement and near normal strength in his leg muscles. He also scored nearly 100% on a questionnaire about knee surgery results.

The authors conclude that “physiologic age and activity level is more important than chronologic age when considering ACL reconstruction.”

When choosing a protective knee brace, research shows that the make and model may affect the speed and agility of an athlete. Thirty football players dressed in full gear were timed in the 40-yard dash and in a four-cone agility drill. Their scores doing the drills while wearing one of six types of braces were compared to their scores when they didn’t wear a brace. The authors found that certain types of protective knee braces do not necessarily hamper an athlete’s performance, either in speed or agility.

Another consideration is how much the brace slides up or down on the athlete’s leg during the sport activity. Measurements were taken to see which braces seemed to hold the best. By placing a mark on the leg, researchers compared how much each brace moved up or down during each drill. The authors noted that the braces tended to move during activity. The athletes were asked how much they thought the brace moved during the drill. Most of the time, their answers didn’t match up to the actual measurements.

This study specifically did not test how much these braces would protect the knee. But according to the authors, the fact that braces showed some movement during the tests “could affect their protective function and athlete performance.”

Many parts of the body are involved in balance, including the eyes, inner ear, neck, trunk, and legs. Balance depends on the reflexes of each of these parts and the communication between them. An injury anywhere in this system can impact balance.

As a major stabilizer of the knee joint, the anterior cruciate ligament (ACL) is crucial to balance. If you tear your ACL, standing on one foot may be difficult. This is because the ligament loses its ability to steady the joint, and the tiny sensors in the knee ligaments, joints, and muscles have difficulty sending information about the joint’s position. Balancing becomes a challenge. But what if you have ACL surgery? Will your balance return to normal?

This study involved 25 patients with mainly sports-related ACL injuries. Eight of the patients were women; 17 were men. Their average age was 27. All of the patients had ACL reconstruction surgery. After surgery, half of them wore casts, and the other half wore braces and started exercises right away to improve knee movement. They all had six to eight months of rehabilitation training to restore the reflexes in their injured legs.

About three years after surgery, patients did a series of balance tests. First, they balanced on one or both feet with their eyes open and then with their eyes closed. Special sensors detected how much patients swayed back and forth in these positions. Next, the patients stood on one foot on a moving surface with their eyes open. Sensors recorded patients’ reaction times and how long it took for them to correct their balance. As a comparison, a group of people the same age with uninjured knees did these same tests.

Since one goal of ACL surgery is to restore the stability of the injured knee, the patients’ knees were also tested for looseness. Their injured knees were still looser three years after surgery than their uninjured knees or the knees of the comparison group.

Even though the operated knees were looser, balance was nearly the same between patients who had ACL injuries and the comparison group–with two exceptions. Patients who had ACL surgery had slower reaction times when the surface beneath them moved. But compared to the other group, they regained their balance faster. This may be because the ACL patients had learned to compensate for their injury.

The results of this study suggest that balance can be restored after ACL surgery. This goal is maximized with a rehabilitation program that focuses on retraining balance in the knee.

The ability to tell where your joints are positioned or how they are moving is called proprioception. Tiny sensors, called proprioceptors, are located in muscles, ligaments, tendons, and joint capsules. They send signals to the central nervous system to keep you in tune with your body’s whereabouts.

This “sixth sense” gets a little fuzzy as we age or when we get fatigued. Scientists thank that joint problems like osteoarthritis can impair proprioception. This recent study investigated whether knee osteoarthritis disturbs sensory signals from the knee.

Researchers used a dynamometer to get precise measurements of joint proprioception. The dynamometer is a machine that can be set to move a joint at a certain speed through a preset arc of motion. It then gives a computer readout of speed, direction, and joint angle. Patients are tested to see if they can tell where their joint is positioned or which direction it is moving.

The authors tested 117 patients who were scheduled for knee replacement surgery because of knee arthritis. First, they compared the results of the patients to people of the same age without arthritis. Second, they compared signals between knees in patients who had one healthy knee and one arthritic knee. Third, they tested whether joint sense was worse in the most arthritic knees.

People with arthritis scored significantly lower than people with healthy knees, supporting the theory that osteoarthritis impairs joint sense. Unexpectedly, people with knee osteoarthritis in one knee showed impairments in the other knee, too, even when it appeared normal on X-rays. And joint sense didn’t necessarily decline as osteoarthritis worsened.

These results made the authors question whether the muscle and ligament problems from osteoarthritis really are responsible for problems with proprioception. The authors speculate that impairments in joint sense might start even before the problems of knee osteoarthritis can be seen. They conclude that further studies are necessary to understand the relationship between problems with joint sense and osteoarthritis.

Asking patients about their pain or symptoms after meniscus surgery doesn’t always give a complete picture of their recovery. A recent study showed that after three months, patients reported that their pain and symptoms had improved–but their capabilities, activity levels, and quality of life hadn’t.

The authors first wanted to get a picture of what doctors expected from recovery after meniscus surgery. They asked 17 surgeons how long it should take patients to recover. Answers varied between two and 12 weeks. The surgeons were also asked what made recovery time longer. Opinions on this topic varied as well. Most surgeons felt that an accompanying injury to ligaments or articular cartilage lengthens recovery time. Others thought that tears in the lateral meniscus, gender, and a longer period of time from injury to surgery could make a difference. One doctor even reported that not being physically active before surgery made the recovery time slower.

The authors then submitted questions to 79 patients who underwent meniscus surgery. This is the first study using specialized surveys to measure patients’ activity levels, quality of life, and ability to function both before and after surgery. The patients answered the surveys before surgery and 14 weeks after surgery.

Results showed that most patients had improved knee movement, swelling, and pain. However, the researchers were startled by the patients’ lack of activity after surgery. Only 30% of patients were active in sports after the surgery, compared to 63% who were active before surgery. Almost 40% reported that they were sedentary after surgery, compared to only 9% before the surgery.

As some surgeons predicted, people with injured articular cartilage and those with significant problems before their surgeries ended up with lower quality of life scores three months after the surgery. But factors like gender, age, and a longer period of problems before surgery didn’t seem to have any impact.

In the final analysis, the authors suggest that having less pain and symptoms doesn’t necessarily tell the whole story about the recovery process. Measurements of function, quality of life, and activity levels gave a much better idea about how patients were doing after surgery. The authors conclude that these types of surveys should be used for patients undergoing meniscus surgery. And based on the results of this study, the authors feel that patients should be given a more realistic idea of what to expect after meniscus surgery.

Over 40 with a meniscus tear in your knee? Nowadays, doctors will probably choose to repair–rather than remove–your injured tissue. Repair is now possible even when the tear is in the avascular zone, the part of the meniscus without blood supply. In the past, doctors hesitated to do repairs in the avascular zone, for fear that lack of blood would keep it from healing.

The meniscus is a crescent-shaped piece of cartilage in the knee. The meniscus acts like a shock absorber to help spread out the forces that press on the knee joint. Without a meniscus, the forces are concentrated onto a smaller area. The meniscus is very important to the long-term health of the knee. Doctors have become aware that surgically removing the meniscus can lead to early arthritis in the knee joint.

This study was designed to test the long-term affect of surgically repairing the avascular zone of the meniscus in a group of 30 patients who were 40 years and older. Rehabilitation treatments after the surgery proceeded cautiously. Patients started out with treatments to help get the knee moving again, but only in a limited zone of movement. They had to wait up to six weeks to work the full amount of knee bend. They were also limited for up to six weeks in the amount of weight they could bear when walking. To further protect the repaired meniscus, they were not allowed to squat down for four months and had to wait at least six months before running, jumping, or twisting the knee.

Researchers followed up on all but one of the patients an average of 33 months after surgery. Six patients needed additional arthroscopic knee surgery for various reasons, so the researchers were able to actually look at the repaired meniscus with the arthroscope. All patients filled out surveys about their sports, work, and general activities, their symptoms, and how they felt about their knee’s recovery.

Fears about poor surgical results in the avascular zone appear to have been unfounded. An astounding 87% of the repairs were symptom-free at follow-up. And 76% of the patients reported that their overall knee condition was “normal to very good.” The authors attribute this success to new advances in knee surgery and the precautions taken during rehabilitation.