News Category: Knee

When it comes to anterior cruciate ligament (ACL) injuries, men and women are as different as Venus and Mars. Women are four times more likely than men to tear an ACL playing basketball. And women soccer players are twice as likely to have ACL injuries as their male counterparts. But how do the sexes compare after ACL surgery? Does one gender show superior results?

Two hundred athletes had ACL reconstruction surgery. The surgeons used part of each patient’s patellar tendon (the tendon just below the kneecap) to replace the ACL. After surgery, patients did a standard physical therapy program. They used a standard knee brace for the first six weeks after surgery. Then they got a custom knee brace.

One hundred thirty-seven of the patients were men. Sixty-three were women. There were some basic differences between the two groups. The women tended to be younger than the men (27 versus 30 years old). Women also had surgery sooner after injury, though both groups typically waited six weeks or more. In addition, women were examined by the authors sooner after surgery than men.

Women and men both seemed to get good results from surgery. There were only a few physical differences between them four months after surgery. On average, men had a harder time getting their knee to straighten fully compared to women, yet the men tended to have slightly better scores on tests of joint stability.

After surgery, both sexes did equally well on athletic jumping tests. They reported the same level of activity and problems with sports. They had the same amount of pain. (It wasn’t severe.) Women and men also had about the same difficulty going up and down stairs.

To study the results of a general health questionnaire, the authors compared the responses of these patients with those of “average” men and women. Women in the study showed greater differences from the comparison group. In particular, the women in the study scored higher than other women on physical activity, body pain, and overall health.

Women and men were both very satisfied with their surgery. Ninety-six percent of men and 98 percent of women said they would choose surgery again.

This study shows that this form of ACL reconstruction can produce equally good results in men and women. Some surgeons believe that grafting other tendons, such as those from the hamstrings, reduces complications in women who have ACL surgery. However, based on these study results, the authors suggest the patellar tendon is still an appropriate choice for female patients having this surgery.

When it comes to knee injuries, orthopedic surgeons depend on the patient’s history and physical exam to find out what’s wrong. Specific tests of structure and function are performed to look for joint instability. In this review article, tests for assessing tibiofemoral and patellofemoral instability are described and explained in detail.

These are two joints in the knee. Tibiofemoral refers to the joint formed by the tibia (lower leg bone) and the femur (thigh bone). The patellofemoral joint is where the patella (knee cap) moves up and down over the femur.

Successful treatment depends on an accurate diagnosis. First the orthopedic surgeon pays attention to the mechanism of injury. Knowing how the injury occurred helps point to the structures involved that might have been torn or ruptured.

The diagnosis continues with various physical tests for anterior (forward) or posterior (backward) joint instability. The tests aren’t always foolproof, so further testing with diagnostic imaging may be needed.

Anterior instability is tested using well-known tests such as the Lachman or anterior drawer test. Injury to the anterior cruciate ligament (ACL) is the main problem when either test is positive. Studies show the Lachman test is more accurate because it puts more strain on the ACL compared with the anterior drawer test.

Other tests for anterior instability include the pivot-shift test and KT-1000 or KT-2000 arthrometer tests. Arthrometer tests are performed with a special device that places three different amounts of anterior force on the tibia.

Posterior instability occurs when the posterior cruciate ligament (PCL) has been ruptured or damaged. Two other ligaments that can be involved with posterior instability include the medial collateral ligament (MCL) and the lateral collateral ligament (LCL). The posterior drawer, posterior Lachman, and sag tests are used to help diagnose a PCL tear.

Besides anterior and posterior instability, there can also be rotatory, valgus, and varus instabilities. Rotation occurs when the knee is bent or flexed. Rotatory instability occurs as a result of injury while pivoting, cutting, or rapid deceleration (slowing down suddenly). Numerous tests for rotatory instability in all directions are presented.

Varus and valgus movements refer to gapping or rocking between the tibia and the femur. Stress tests can be applied when looking for damage to the collateral ligaments. The knee is placed in full extension during the first test. The test is repeated with the knee bent 30 degrees. Each position tests for specific ligament injury.

The authors also discuss the angle of the patella called the Q-angle, movement of the patella over the joint called patellar tracking, and tests for both.

With all of these tests, false-negative results can be avoided with patient relaxation, proper positioning, and by applying the correct direction of force. Following the recommended technique for using each test is important for accurate results.

It borders on common sense. Ice is an effective first aid choice for many ailments–bumps, bruises, and even insect bites. Now it makes “scientific sense” how cold treatments play a major role in helping patients get better, faster after orthopedic surgery.

Called cryotherapy, cold treatments are believed to help ease pain, swelling, and inflammation after surgery. Cryotherapy even helps patients improve faster using fewer painkillers. Past studies have proven that patients given cold treatments after knee surgery generally recover more quickly, gaining joint movement faster and finding it easier to get up and walk.

However, these studies have only shown a drop in temperature on the skin’s surface. This is the first human study to show how applying cryotherapy after knee surgery can lower the temperature inside the knee joint.

Seventeen patients had knee surgery. After surgery, a special cooling wrap was placed over each patient’s sore knee. Twelve patients began their cold treatments immediately after surgery. The other five waited one hour.  

The researchers measured the temperature inside the knee joint with a special probe. Readings were taken hourly after surgery. After one hour, the people who used cold treatment immediately after surgery showed a marked drop in knee temperature. The other patients’ knee temperatures went up. Remarkably, there was over 7 degrees of difference between the two groups after one hour.

The second group started their cold treatments after waiting one hour. Even though their knee temperature had gone up at first, starting cold treatment one hour after surgery caused a marked drop in temperature, about 4 degrees.

The researchers didn’t study how well or how quickly the patients healed. Yet their findings suggest that cooling the inside of the joint after knee surgery must be a major reason cryotherapy works.

Ligament injuries in the knee often have an effect on other parts of the knee. Upon impact, the surfaces of the knee joint may slam into one another, bruising the bones. These bruises are actually tiny fractures of the bone underneath the cartilage. X-rays don’t often show the bruises on the bone, but MRI scans can.

Researchers in Argentina set out to discover whether a bruised knee bone results in ongoing problems in the knee joint. They did an MRI scan on patients scheduled for surgery to repair a torn anterior cruciate ligament (ACL) in the knee. Participants were included in the study if this was their first knee injury and the MRI showed a bone bruise. Twenty-one people with a total of 29 bruises were found. The bruises were graded based on severity: type I being the mildest and type III being the most severe.

Within two to three years after surgery, another MRI was done. Most (91 percent) of the milder bruises disappeared completely. Yet none of the type III bruises went away. Even though the bruising appeared to resolve, this did not mean the bone had healed. In fact, the follow-up MRI scan showed that one-third of the patients still had an indentation in the bone where the bruise occurred. Others showed thinning in the cartilage of the knee joint. 

Do these findings matter? Scientists believe they do. The concern is that the initial bone injury eventually causes the bone to become less resilient–less “bouncy.” With the shock absorbers down, the cartilage that covers the knee joint takes more force. So even though the ligament has been successfully reconstructed, the hardening in the bone may lead to arthritic changes in the knee joint.

The researchers concluded that it isn’t possible to predict long-term bone damage by whether or not the bone bruising has gone away.

Patellofemoral pain syndrome (PFPS) is basically pain in front of or behind the kneecap (the patella) that doesn’t always have a clear cause. PFPS is a common knee condition, especially among athletes. The pain is often felt after sitting for a long time, going up and down stairs, and when squatting or kneeling. There are many causes of PFPS. Knowing these causes could help health care providers choose the best treatments.

Medical researchers have long believed that abnormal tracking of the patella may contribute to problems of PFPS. The patella normally runs (tracks) in a groove on the front of the thigh bone (the femur). Two muscles of the thigh–the vastus medialis obliquus (VMO) and the vastus lateralis (VL)–attach to the patella and help control its position in the groove as the leg straightens. The VMO runs along the inside of the thigh, and the VL lies along the outside of the thigh. If the timing between these two muscles is off, the patella may be pulled off track.

The theory sounds nice, but does it really happen that way? These researchers tested how the VMO and VL work during stair climbing in 33 people with PFPS and 33 people with no knee pain (the control group). Electrodes were placed over the two muscles to get an electromyograph (EMG) reading of the activity in the muscles. The subjects then went up and down two stairs at a normal pace. As expected, the group with PFPS felt pain during the test, and the control group felt no pain.

Researchers found a significant difference between the way the muscles worked in the two groups. The EMG signals happened at the same time in most of the control group. In the group with PFPS, the VL muscle kicked in well before the VMO muscle, both going up and going down the stairs.

This research supports the theory that patellar tracking is partly to blame for PFPS. However, the results also raise many questions. There was a wide variation in onset of EMG signals within both groups of subjects. So how much difference in timing is too much? Not everyone with PFPS has problems in the timing between the two thigh muscles. Why not? Does their PFPS have a different cause? Also, it is impossible to tell from this study whether the differences in muscle timing happened before problems with PFPS developed, or if the differences were actually the result of a painful knee from PFPS. More research is needed, but the current trends in rehabilitating PFPS are on track with the findings of this study.

All it takes is a good whack to your knee, and the surrounding muscles may decide to stop doing their job. Your injury is called a patellar contusion–a blow to the kneecap. You will have pain and most likely weakness in the quadriceps (the big muscle on the front of your thigh). What is the best way to get your quadriceps strong again?

That depends on whether the weakness is caused by quadriceps atrophy or inhibition. Atrophy means that the muscle is weak and shrunken. In this case, atrophy could happen because the pain in the knee causes you to use that leg less. Inhibition means that the muscle just can’t engage when you try to move it. The pain and swelling are believed to throw the nervous system off, keeping the muscle from working.

The difference between atrophy and inhibition is important, because the two conditions need to be treated differently. Atrophy is treated by strengthening the muscles. Inhibition requires that the muscle be “re-educated” using specialized therapy, such as electrical stimulation.

If clinicians could easily tell the difference between inhibition and atrophy, they could design better rehabilitation programs. These authors set out to identify inhibition in people with patellar contusions. Sixteen patients who had been injured less than four months earlier were tested. Patients answered questions about their activities and knee function. Researchers then used a special kind of electrical test as the patients contracted their quadriceps. The test was also run on each patient’s uninjured leg as a comparison. Inhibition was documented if the muscle could give a bigger effort when the electricity kicked in.

The authors expected to find that most of the patients had quadriceps inhibition. All the patients had weaker quadriceps muscles on their injured legs. But the results showed that less than one-third (a total of 5) of the patients showed signs of actual inhibition. And the questionnaires about pain and activity didn’t give any clues as to which patients had quadriceps inhibition, either. (People with inhibition would be expected to have lower scores on these types of questionnaires.)

So the search is still on for a good way to diagnose inhibition after patellar contusion. As it is, it’s not an easy task to tell the difference without high-tech testing equipment. Knowing the difference could help patients get the best treatment right away– turning the knee muscle that wouldn’t into the knee muscle that could.

Surgeons can reconstruct a torn anterior cruciate ligament (ACL) of the knee in several different ways. One technique involves taking a piece of the patient’s hamstring tendon and using it to replace the torn ACL. Some doctors believe that this technique should not be used in chronic cases where the ACL ruptured several months before surgery.

These authors studied 120 patients who had the same type of ACL surgery using a hamstring tendon graft. Sixty-one patients had an ACL reconstruction within six weeks of their injury (the acute group). The remaining 59 patients had ACL reconstruction longer than six weeks after their injury (the chronic group). The goal of the study was to compare how well the two groups did after surgery.

The subjects were evaluated between two and six years after ACL reconstruction. They filled out questionnaires about their levels of pain and activity before surgery and at follow-up. They did physical tests of knee strength and stability. Researchers also checked subjects’ medical records for information about their knee condition.

Results showed that, overall, ACL reconstruction using a hamstring tendon was successful. At follow-up in both groups, about 94% of the knees were rated as normal or nearly normal for function, with results being somewhat better in the acute group. The authors believe this may be because the chronic group tended to have more damage to other parts of the knee joint.

All kinds of people–mostly athletes–tear the anterior cruciate ligament (ACL) in the knee. Most times, the torn ACL is replaced surgically using a piece of either the patient’s patellar tendon or hamstring tendon. It is thought that both types of tendon grafts work about equally well. Only problem is, there’s not much research to support that theory.

These authors pooled four clinical trials together to compare the results of patellar grafts and hamstring grafts in ACL reconstruction. All totaled, the four studies included 424 patients, 234 of whom had ACL reconstruction using the patellar graft and 190 who had a hamstring graft. The studies had their differences. But they were all high quality research that evaluated patients’ return to activity, knee function and range of motion, complications, and failures after surgery.

There were no significant differences in the rate of complications or failures between patellar and hamstring tendon grafts. However, there was a measurable difference in the stability of the grafts and patients’ ability to return to activities. Patients who had patellar tendon grafts showed a 20% greater chance of returning to their pre-injury level of activity and had a better chance of having a more stable knee.

Both types of grafts have good results. Still, the authors feel that the results of this study were valuable, and suggest that patellar tendon grafts might be the best choice for most ACL reconstructions. They suggest further research on complications that can develop from removing a graft from the thigh or knee. And they recommend that further research include patients’ opinions on their recovery. They believe patellar tendon grafts appear to be the clear winner for most ACL reconstructions, compared with hamstring tendon grafts.

Reconstruction of the anterior cruciate ligament (ACL) of the knee has become a common surgery. It is estimated that orthopedic surgeons do more than 100,000 ACL reconstruction surgeries each year in the U.S. alone. The long-term success rates are somewhere between 75% and 90%. As good as that is, it still leaves an awful lot of people who face ongoing problems or a second surgery to fix an ACL reconstruction with poor results.

Revision surgery is done to fix problems that occur after an earlier surgery. Revision surgeries on a reconstructed ACL can be very tricky. In this article, the authors give an overview of treatment for failed ACL reconstruction. They discuss reasons for failure and a systematic approach for doctors to take in these cases.

The authors stress that it is especially important to figure out why the reconstruction failed in the first place. There are many possible causes of ACL reconstruction failure. Was it related to ligament laxity or other problems in the knee? Was it related to doing too much before healing, surgical technique, or graft failure? Early failure–within six months–tends to be related to problems stemming from the surgery or overly aggressive rehabilitation. Failure that occurs over a year after revision is more often due to a new injury.

The authors list surgical problems that can cause failure. Many factors, including surgical technique and abnormalities of individual knees, can contribute to surgical problems:

• missing the mark in the knee bones where the ligament should go


• not lining the ligament up right, causing it to get pinched as the knee moves


• not placing the right amount of tension on the graft


• not securing the graft tightly enough


• damaging the graft ligament when it is being implanted


• not treating other problems in the knee, including other ligaments that are too loose to hold the knee in proper position


• failure of the graft to heal well and to become part of the knee


• re-injury of the knee after surgery, which happens in up to 10% of athletes.

• a detailed medical history


• a detailed physical examination, which focuses on the anatomy of the injured knee and the way it moves


• various imaging tests–X-rays, bone scans, CT scans, and possibly an MRI–to learn as much as possible about the knee’s condition and the problems with the original surgery.

The authors conclude that it is especially important that surgeons be clear with their patients about the problems with revision surgery on the ACL. It is a complex surgery, and it is impossible to predict its outcome. The results are usually not as good as those of first ACL reconstruction surgeries. ACL revision requires the best efforts of both the surgeon and the patient.

Total knee joint replacements (also called total knee arthroplasty, or TKA) is a common surgery to ease the pain of arthritic knees. TKA used to require a long hospital stay with plenty of bed rest. These days, patients who get a TKA begin physical therapy right away, and they leave the hospital within a week. There is no time for bed rest in this new style of treatment. Research has consistently shown that getting a move on speeds up the healing process and increases the knee’s range of motion faster.

But questions remain as to what kind of mobilization is best. Most hospitals use a continuous passive motion (CPM) machine. A CPM device straps to the leg and constantly bends and straightens the leg while the patient lies in bed. CPM is expensive therapy that demands lots of medical attention and bed rest. There is no clear research to prove its effectiveness.

Slider boards are another form of passive mobilization. The patient’s heel is hooked into a cup on a board that slides freely up and down in a frame. The knee bends and straightens just like with the CPM machine, but the patient is actively part of the treatment. The boards can be used sitting or lying down. They are also cheap and require little medical help to use.

This study divided 120 patients who had gotten a TKA into three groups. While in the hospital, the first group did the standard exercise program along with an average of 1.7 CPM treatments per day. The CPM sessions lasted a little over an hour and a half. The second group did the standard exercise program and slider board sessions. They did an average of 1.7 slider board sessions each day, for an average time of 16 minutes per session. The third group did the standard exercise program only. The standard exercise program involved working with a physical therapist for about 30 minutes, including ice treatments before and after exercising.

All three groups went through the same series of tests before TKA, before discharge from the hospital, and three and six months after surgery. They filled out questionnaires about their general health and their knee pain and function. They also did tests of knee range of motion.

The results showed no differences between any of the three groups in any of the measurements three and six months after TKA. All together, 96% of subjects reported less pain and 82% reported better function at six months. Although this study showed less range of motion at hospital discharge than other studies of CPM machines, knee range of motion was comparable at the three- and six-month follow-up tests.

The results made the authors question the use of both CPM and slider boards. The conclude that, as long as patients who have had TKA just get a move on it, the extra treatments don’t add anything to standard exercises.

Recovering from total knee replacement (TKA) surgery involves pain. Pain relief medicine is a standard part of treatment after surgery. Pain relief is important–and not simply to ease the distress and discomfort of pain. The saying “no pain, no gain” is just not true when it comes to knee replacement surgery. Pain makes it harder to move and exercise the knee, which slows recovery. Pain also affects the muscles and other soft tissues around the knee. 

Pain relief is not practiced consistently in hospitals and rehab centers. Most often, patients are given fast-acting opioids when they ask for them. (Opioids are strong pain killers that must be used with caution because they can be addictive.) This means that patients get sporadic pain relief only after their pain has built up to the point that they have to ask for help.

These researchers tested whether regular doses of a long-acting opioid called oxycodone would help patients recover faster from knee replacement surgery. Patients recovering in an inpatient rehabilitation hospital were divided into two groups. The first group of 29 patients got the long-lasting oxycodone twice a day. They could also ask for fast-acting oxycodone if needed. The placebo group of 30 patients got capsules twice a day that looked like the oxycodone but contained no medicine. They could also ask for pain medicine as needed. Other than that, both groups were on the same schedule of medications, physical therapy, and other treatments.

The patients were checked before and after undergoing eight physical therapy sessions. They answered questions about their pain and did functional tests. At the first session, the two groups showed about the same test results. But by the last session, there was a marked difference. The patients who had gotten the long-acting oxycodone had greater improvement in all functional tests. They were also discharged from the hospital an average of 2.3 days earlier than patients in the placebo group. Patients in the placebo group were also a bit more likely to be discharged to home physical therapy or transferred to another inpatient rehab center.

The authors conclude that regular, strong pain relief can be a big help in getting knee replacement patients back to full function. These patients experience less pain, recover knee strength faster, and need less continuing health care. In other words, these patients had less pain, but more gain.

Injury to the anterior cruciate ligament (ACL) of the knee has become common, especially in athletes. Rehabilitation after ACL surgery is especially important for athletes, since they put heavier demands on their injured knees. Rehabilitation professionals are currently debating whether open or closed chain kinetic exercises are best for people after ACL surgery. In open kinetic chain exercise, the leg is free to move in various directions. In closed kinetic chain exercise, the leg is fixed to a surface as the joints closer to the body work.

Recent evidence has suggested that closed chain exercises are safer and have better results after ACL reconstruction. But very little research has been done to directly compare the two types of exercises. These authors followed 37 patients through four weeks of therapy following ACL surgery. The patients were divided into two groups. One group did open kinetic chain exercises as part of their standard physical therapy. They used ankle weights or knee and hip extension machines. The other group did closed chain exercises on a leg press machine. (Squats are the closed chain exercise normally used in rehabilitation, but the injured leg needed to be exercised alone for the purposes of this study.) Both groups did the special exercises only for their affected knee.

Researchers studied the gait, or walking motions, of the patients to see how physical therapy affected their knees. Researchers measured the movements of the knee joint while walking, going up stairs, and coming down stairs. The gait studies were done two and six weeks after surgery. In between gait studies, the patients saw a physical therapist three times a week.

The injured knees in both groups improved significantly over the course of the study. Researchers saw very little difference between the two groups. However, they did see some extra improvement in the stair climbing mechanics of the group who did open chain exercises. The difference was small, however. The patients may not have noticed any difference.

The findings of this study reopen the argument on open versus closed chain exercises. But the authors caution that more research is needed before a winner is declared in this ongoing debate. There is a need to better understand how open and closed chain exercises affect a knee after ACL reconstruction surgery.

Tendon injuries are common in athletes. Patellar tendonitis, also called “jumper’s knee,” is an overuse injury that causes pain at or near the kneecap (the patella). Medical professionals know that such factors as intense training, poor training techniques, or improper shoes can lead to patellar tendonitis. However, under the same conditions, some athletes develop patellar tendonitis and some don’t. These researchers wanted to find out if there were any differences between those two groups of athletes.

The researchers studied 138 physical education students in Belgium for two years. At the start of the study, the students underwent a series of tests to measure such physical characteristics as leg length and alignment, muscle tightness and strength, height, and weight. The students were examined every three months by a doctor and orthopedic surgeon. By the end of the study, 19 of the 138 students (about 14%) had developed patellar tendonitis.

The researchers then compared the measurements of the group who had developed patellar tendonitis with those who hadn’t. Both groups had taken part in the same types of sports for about the same amount of time. They also had similar results on all physical measurements–except one. The group who developed tendonitis tended to have less flexibility in their quadriceps and hamstring muscles at the beginning of the study.

This study involved only a small group of students. The authors caution that more research is needed to further understand what factors cause patellar tendonitis. They suggest that future studies focus on bigger groups and compare athletes within the same sport. But the authors also feel that stretching is in order for athletes who don’t have good flexibility in their hamstrings or quadriceps. Stretching could also be useful for athletes recovering from patellar tendonitis.

The anterior cruciate ligament (ACL) is a major stabilizer of the knee joint. This key knee ligament is commonly torn during sports activities. One of the most common ways that doctors repair a torn ACL is by taking out the middle section of the patellar tendon below the knee cap. This new graft includes the strip of patellar tendon, along with attached plugs of bone on each end. The doctor implants the new graft into the knee, making sure to line it up just like the original ligament.

The patellar tendon graft is reported to be one of the strongest types of graft material available for ACL reconstruction. However, there have been questions about how well this method of reconstructing the ACL holds up over time.

These authors followed up on 32 patients who had arthroscopic surgery using the patellar tendon graft. The arthroscope was used to implant the new graft. The arthroscope is a tiny TV camera inserted through a small incision. It allows doctors to look inside a joint while reconstructing the knee.

The 32 patients were followed over five years after their ACL reconstruction using this procedure. The patients did physical tests and answered questions about their pain and activities both before their surgery and five years later. These physical tests compared the patients’ operated knee with their other knee.

Roughly 87% of the knees were classified as having good surgical results based on knee stability testing. The survey comparisons showed that 78% of patients were now doing a higher level of activities than they did before their ACL reconstruction. And 40% of patients had gone back to activities from before their ACL injuries.

The authors report that these findings are similar to results from other procedures used to repair torn ACLs. They conclude that this type of graft implanted with the assistance of an arthroscope shows good long-term results in surgical treatment of ACL ruptures.

In almost any group of athletes, there will usually be someone wearing a knee brace. Knee bracing has become a common way to give extra support for problem knees. Often, doctors and therapists prescribe knee braces to their athletic patients who have had knee reconstruction surgery of the anterior cruciate ligament (ACL). But medical research shows conflicting evidence about how–and how well–knee bracing works.

In this study, 31 subjects were tested in three different situations: wearing a commonly used knee brace, wearing a brace that didn’t really provide any support (the placebo brace), and wearing no brace at all. Researchers measured the subjects’ performance as they ran around a figure-eight track and as they ran, turned, and landed on a marked spot. The idea was to test the braces under the conditions of real sports that involve a lot of turning, stopping, and jumping while running. All 31 subjects had undergone ACL reconstruction surgery at least five months before the tests.

The researchers found that bracing had little effect on most of the measurements. However, both the real brace and the placebo brace actually slowed down running and turning times. The subjects were significantly faster without a brace. Surprisingly, over half of the subjects reported that they preferred using the brace. While bracing may not give true knee support, it may offer psychological support.

The authors conclude that their study showed no reason to use knee braces to improve athletic performance after ACL reconstruction. However, they caution that braces may still be useful in some cases. Patients whose knees are loose and unsteady despite surgery might see some benefits from using a brace. Also, a study of nonathletic patients might show somewhat different results.

Chondromalacia is a softening of the articular cartilage that protects the ends of bones and allows smooth movement in our joints. When the condition develops in the patella (kneecap), doctors sometimes call it chondromalacia patella. But do the symptoms people feel always come from changes in the surface of the patella? Some people report feeling symptoms of chondromalacia patella, but they have no visible changes in their cartilage. And some people feel no symptoms, yet they show changes within the cartilage. Go figure.

Doctors commonly check for this condition during a physical examination of the knee. But it is unclear how accurate these tests really are. These researchers compared the results of tests used in the physical exam to the results of an arthroscopic exam in 85 patients with knee problems. The arthroscope is a tiny TV camera inserted through a small incision. It allows doctors to look inside a joint to make a more accurate diagnosis. The researchers found that the physical tests just didn’t measure up.

The researchers performed four different physical tests on the patients. They also measured the patients’ thighs, to see if muscle atrophy could help in diagnosing the problem. Among the tests, only the flexion test had much relation to patellar chondromalacia. In a flexion test, the doctor holds the leg at its maximum flex point to see if the extra pressure under the kneecap causes pain. This test correctly identified people who did not have the condition 85% of the time–but it only identified people who actually had the condition 35% of the time. The authors tried to analyze the data a number of different ways to see if they could find any strong relationship between the tests and the condition, but they couldn’t.

The authors conclude that none of the four physical tests is accurate enough for doctors to rely on in making a diagnosis of chondromalacia patella. Because it is invasive, arthroscopy is not a standard way to diagnose the problem. And changes in the bone under the layer of cartilage may be just as important in the development of chondromalacia, and these changes can’t be seen through an arthroscope. Clearly, practitioners treating people with knee problems need tests that measure up to the task of diagnosing patellar chondromalacia.

Reconstruction of the anterior cruciate ligament (ACL) of the knee is a common surgery. One of the reasons for ACL reconstruction is to prevent the development of osteoarthritis (OA) of the knee. In an attempt to fix the ligament, though, OA can sometimes develop where the patella (kneecap) and femur (thigh bone) meet. This joint is called the patellofemoral joint.

The authors of this study followed up on 100 patients who had undergone ACL reconstruction surgery about seven years earlier. All patients had a follow-up physical examination, answered questions about their pain and function, and had knee X-rays taken. These latest results were compared with the patients’ records from before and just after surgery.

Of the 100 patients, follow-up X-rays showed that 53% had no sign of OA. Of the remaining patients, almost half ended up with some amount of degeneration. Mild degeneration was seen in 34%. Another 12% had moderate degeneration, and 1% had severe degenerative changes. Not everyone who had signs of OA felt pain or significant symptoms, however.

The X-rays showed a link between patellofemoral OA and a shortened patellar tendon. The worse the OA, the shorter the patellar tendon. The authors suggest the two may go hand-in-hand. There also tended to be a connection between patellofemoral OA and the spot where the tendon graft was placed. The incidence of OA was higher when the graft was placed slightly forward on the femur and further back on the tibia. 

It is impossible to tell from this study how much the original knee injury, the type of surgery, or immobilization after surgery affected the development of OA. It is possible that newer surgical techniques using the arthroscope could show a lower rate of post-surgical OA in the patellofemoral joint. Patients usually don’t immobilize their knees during rehabilitation anymore, either. This study can help give a baseline to see if newer techniques are any better at preventing the “seven-year hitch” of post-operative OA in patellofemoral joint.

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.