News Category: Knee

Tears of the anterior cruciate ligament (ACL) of the knee are fairly common, especially among athletes. ACL tears most often require surgery. Most people who tear the ACL are younger and active. They want the best knee function possible after ACL surgery. Surgeons are constantly trying to fine tune their ACL reconstructions.

This author studied the difference between two common types of tendon graft. The semitendinosus tendon is from one of the hamstring muscles on the inside edge of the thigh. The patellar tendon is attached to the kneecap. Both have been used successfully to reconstruct the ACL.

This study looked at 40 male soccer players in Germany. All had ACL tears repaired by the same surgeon using the same technique. All followed the same rehabilitation program. But some had semitendinosus tendon grafts, and some had patellar tendon grafts. Both groups were tested at least two years after surgery. They answered the usual questions about their activities and knee function. They did the usual tests of strength while bending and straightening the leg. They were also tested doing jumps and squats and walking.

The results were similar for both groups in the usual questions and strength tests. However, the functional tests showed important differences. The group who had semitendinosus grafts flexed their knee more fully during jumps and squats. They depended less on the muscles surrounding the knee. They also walked with a more even gait.

The author notes that standard strength tests and questions did not show the differences between the groups. The results of the extra tests seems clear. According to this study, semitendinosus grafts gave better knee function than patellar tendon grafts.

How do you know when it’s time for a knee joint replacement? When pain is not relieved by any other means. Quite often, the patient has severe arthritis as seen on X-ray.

A 75-year old woman with a leg amputation below the knee is presented in this report. Her case is unusual because most people with an amputated leg have less arthritis in that leg. They tend to use the “good” leg more and favor the amputated side, putting less stress on the joint.

In this case the patient had severe arthritis in both knees. At first she had the knee replaced on the nonamputated side. When she could no longer move the knee on the amputated side, that knee joint was replaced. A joint replacement on an amputated leg has more than the usual risks. For this woman, decreased blood flow led to the amputation in the first place. A joint replacement increases her risk of a second amputation further up the leg (mid-thigh).

Physical therapy started the day after surgery. She went home on the eighth day, when she could use a wheelchair without help. Eight months later she was pain-free and could walk without help up to 100 yards (the length of a football field).

The doctors on this case report that the joint replacement operation was modified a little for a leg amputation below the knee. They show a good result with joint replacement first on the nonamputated side. This way the patient could put weight on the nonamputated side when the time came time to replace the second knee.

The authors conclude that a knee joint replacement is possible for someone with severe arthritis in the knee of an amputated leg.

Athletes often tear the anterior cruciate ligament (ACL) in the knee. ACL tears can be devastating. They most often require surgery. They generally require a long period of rehabilitation. Rehab can help return people to their sports and activities. But the reconstructed ACL almost never regains its full strength. Therapists are working to figure out better rehab programs after ACL repair.

As part of this effort, these authors studied how ACL repair affects the way patients do squat exercises. Squats are a big part of most ACL rehab programs. Squats use the common motions of sitting, standing, and lifting. Squats also involve coordinating joints in the knees, hips, and ankles. It has been thought that exercises that use multiple joints are better for rehab. This study casts some doubt on that theory.

Researchers tested eight people who had ACL repair less than a year before. They did squats using fairly low amounts of weight. Joint movements and muscle activity were monitored. Results from each subject’s injured leg were compared to results from the healthy leg.

The authors found differences in how subjects used their legs. They did the squats in a way that shifted the force away from the injured knee. In the healthy leg, the effort was divided evenly between hip muscles and knee muscles. In the injured leg, the effort was greater at the hip. It is also possible that more of the work was shifted to the healthy leg.

Shifting the effort away from the injured knee could slow recovery. To get stronger, the knee needs to take on its fair share of the work. This pattern of transferring the work could mean less strength in the injured knee. It could also set patients up for another injury. The authors say that therapists should maybe think again about ACL rehab programs. Perhaps the program shouldn’t involve only exercises that work multiple joints. These exercises may be making it too easy for patients to shift the work to other joints and muscles.

Doctors, sports trainers, and physical therapists are scratching their heads about something. Women are up to eight times more likely to injure the anterior cruciate ligament (ACL) of the knee in the same athletic activities as men.

Even more puzzling is the fact that these injuries are more likely to occur without contact with any other player. Researchers have found some possible risk factors. They include hormones, knee angle, and joint laxity. Muscle strength, knee stiffness, and type of sports may also make a difference.

Physical therapists are teaming up to explain this problem. This study looks at differences in knee joint rolling and gliding between men and women. Rolling occurs when both sides of the joint move against each other. Gliding occurs when only one side of the joint moves on the surface of the other.

These researchers also measured muscle activity and compared women to men. The quadriceps muscle along the front of the thigh and the hamstrings muscle at the back of the thigh were the two key muscles studied.

The authors report a difference in rolling and gliding between men and women. Men tend to roll at the very end of extension (straightening the knee). Women roll and glide throughout the motion. The amount of rolling and gliding is the same whether the foot is planted firmly on the ground or lifted off the ground. Greater rolling and gliding means more joint surface is involved. With more joint surface motion comes more strain on the ACL. This increases the risk of injury.

Differences in muscle activity between men and women weren’t noticeable. Men tended to use the hamstrings more when extending the knee. The authors conclude that the way the joint moves with increased joint surface gliding may put greater strain on the ACL in women. Less hamstring activity at the same time may add to the risk of noncontact injury.

Did you know that, for many people with knee osteoarthritis, only part of the joint is affected? Most often the inside edge of the joint, called the medial compartment, is damaged. A large loss of joint cartilage here puts more pressure on the bone. The angle of the knee can also begin to change. Then the joint may become unstable. Is a total knee replacement really needed if only part of the knee is damaged with osteoarthritis?

Not always. When only one compartment is a problem, the most common treatment is an osteotomy. The doctor removes a piece of bone and realigns the joint. A second option is a unicompartmental knee arthroplasty (UKA). With this implant the joint is realigned using a plastic spacer placed on only one side of the knee joint.

There are some problems with the UKA, and outcomes have varied. The benefits are intriguing enough that doctors are looking for ways to improve the results. For example, not as much bone is lost with the UKA, and the ligaments inside the knee are saved.

In this study doctors in Japan found that better results occur when the knee has full extension. Releasing soft tissues in and around the knee to gain motion may be needed when using the UKA. The authors conclude that choosing patients with full knee motion and improving the operation itself can help increase success with UKA.

Artificial knee joints are being used in younger patients these days. Younger patients are more active. They demand better function and strength after knee replacement surgery. Doctors are trying to understand how much knee strength is possible after a knee replacement. They also want to know what would help patients regain the most strength and function.

This study took a step toward finding answers. The authors tested knee strength in patients who had knee replacement surgery at least two years earlier. The authors also tested knee strength in healthy patients. Strength was tested while bending and straightening the leg. Results showed that patients with a knee replacement had about 30 percent less strength both bending and straightening.

The results also showed that patients over 70 and patients who were heavy generally had less knee strength. Women, who account for most total knee replacements, also had more problems with strength. The authors suggest that therapists work especially hard to find good rehabilitation programs for these groups of patients.

The authors say that many factors may be involved in lowering knee strength after joint replacement. There may be muscle wasting from lack of use, problems with the design of the new knee joint, or problems with surgical techniques. All these factors might work together. Whatever the cause, research such as this can help doctors and therapists plan better rehabilitation for patients who have knee replacement surgery.

When a knee joint is replaced, you may or may not keep your own kneecap (patella). Sometimes the patella is too worn or brittle to work smoothly with the new implant.

If the doctor sees that the patella can be kept, the next decision is whether to smooth the backside. This is called patellar resurfacing. Shaving the patella may reduce painful symptoms, but there is a risk of problems. Patellar resurfacing can cause fracture or dislocation of the kneecap. The muscle that attaches to the patella (called the quadriceps muscle) can also get injured.

Right now, doctors have three choices: resurface every patella, never resurface, or only resurface when it’s truly needed. Resurfacing is always advised when rheumatoid arthritis or other problems are affecting the cartilage on the surface of the patella.

The authors of this study report no difference in outcomes between patients with and without patellar resurfacing. They studied the two groups over a period of 10 years. Pain, range of motion, walking, and stair climbing were used as measures. The main difference is that patients who had a resurfaced patella reported greater satisfaction with the results. Researchers are scratching their heads over that one. It may be that the test used to measure knee function didn’t focus on the kneecap. The survey of satisfaction did.

The bottom line is that knee joint replacement with or without patellar resurfacing reduces pain and improves function. Patients are happier with the results when the patella is smoothed out. Many doctors remain wary of the problems that can occur with resurfacing. However, this study reported a very low rate of problems.

More and more studies show that controlling patients’ pain and getting them moving after a total knee replacement (TKR) gives the best results. Doctors are looking for ways to do this.

Managing patient’s pain in the first 24 hours after surgery seems to be an important key. Better pain control is gained by giving the patient general anesthesia along with a local nerve block at the time of surgery.

One of the nerves often blocked is the femoral nerve, which forms from nerve roots in the low back and runs down the front of the thigh. Blocks are also done to the sciatic nerve. The sciatic nerve is a major nerve that goes down the back of the thigh to the lower leg and foot.

This study compared a femoral nerve block alone to a “double block” of the femoral nerve and the sciatic nerve. Pain levels and amount of opiate used were measured every four hours for the first 24 hours. The authors found that patients receiving the double blocks used less pain medication after TKR than those getting just the femoral nerve block.

With less opiate use, patients have less nausea and fewer chances of lung problems after this surgery. They also get up out of bed and start moving sooner. The authors conclude that sciatic nerve block added to femoral nerve block during a TKR is a good idea.

Predicting success after total knee arthroplasty (TKA) isn’t always easy. Patients want to know what to expect and how long it will take to recover. Doctors don’t have a lot of research to use when advising patients.

This study looked at the rate of recovery for mobility in the first six months after TKA. The authors set out to find factors that affect results, such as age, weight, type of joint implant, pain, and other medical problems. It’s likely that some factors are more important than others. They tried to rank these factors.

Stair climbing and walking speed were used as the main indicators of success. Measures were made one week before and three and six months after the operation. Researchers thought knee strength and range of motion would affect recovery the most. When it was all said and done, two factors were most important. These are quadriceps muscle power and body mass index (BMI). The quadriceps is the muscle on top of the thigh that straightens the knee. BMI is the current way to measure obesity.

Being overweight with decreased muscle power appears to put patients at risk for failing to recover mobility after a TKA. The authors suggest that exercise and weight management will help patients regain stair climbing and walking abilities. They don’t know if it’s best to strengthen the quadriceps muscle before or after the joint replacement. More studies are needed to answer this question and to show if such a program would give lasting results.

What to do? Your knee joint replacement needs replacement (a procedure called artificial joint revision). But your bone is thin and has lost density. It may not be strong enough to support another joint implant.

You may be a good candidate for an implant with a long stem placed down deep into the lower leg bone bone. This type of stem is called an intramedullary stem. Doctors at the Mayo Clinic advise using cement to hold this type of stem in place. Cement is used when the area of bone-to-implant contact is limited.

How well does this treatment choice hold up over time? The results of this study are positive for this option, even after 10 years. In almost 97 percent of the cases, the implant held up well, and no further surgery was needed.

There is an ongoing debate about whether cement is needed or not. Using cement gives a firm hold right away, but it’s harder to remove the implant later if there’s a problem. Antibiotics can be mixed in with the cement to prevent infections.

This was the longest study ever of cemented, long-intramedullary stem use in knee joint implants. The doctors at Mayo are satisfied that cement should be used with most stems of this type. They advise using cement when the joint has to be revised after the first implant fails and when bone density is decreased.

Unicompartmental knee arthroplasty (UKA) is the replacement of just one side of a knee joint. It’s used most often for osteoarthritic changes on one side of the femur. The femur is the thighbone, which has two rounded, knuckle-like projections where it meets the knee. These bumps are called condyles. The condyles form the top half of the knee joint. A UKA
replaces one of the condyles.

These authors report the case of a 66-year-old woman who had a lateral UKA. In a lateral UKA, the outer condyle of the knee joint is replaced. Everything went well for about 16 months. Then she started having pain along the outside edge of her knee. It was persistent, especially when she bent her knee. The doctors thought there might be a loose piece of cement or plastic in the joint.

An arthroscopic exam was done. In this procedure, the doctors insert a long, thin instrument with a tiny camera into the joint. The camera projects onto a TV screen so the doctor can see the inside of the knee. In this case, the doctors could see that her meniscus (cartilage) was getting caught between two parts of the implant.

A special hook was used to free the meniscus. It was then shaved down so it couldn’t get caught again. The patient was pain-free right after the operation. By the end of two weeks she had almost all her motion back. Within six months she had regained her knee strength as well. The authors conclude that arthroscopic exams can be done after a UKA. Care must be taken to avoid infection, but the operation is safe and simple.

Can knee pain can be reduced by just slapping a piece of tape across the kneecap (patella)? A new study has questioned previous opinions about treating patellofemoral pain syndrome (PFPS) by using specific methods of taping. PFPS is a common cause of knee pain. Anything that pushes the patella against the bone causes pain. This includes such activities as climbing stairs, squatting, and sitting with the knee bent for a long time. Scientists aren’t really sure what causes PFPS.

In the 1980s, Jennifer McConnell, a physical therapist from Australia, found a new way to treat this problem. She used tape to hold the patella in place. Each patient was carefully examined for the proper tape placement. This treatment is now called the McConnell Method.

In this study researchers used tape on the knees of 71 patients with PFPS. Each patient was tested without tape and again with tape in one of three places. The patient’s pain level was measured when stepping down one time.

The authors report their surprise to find that tape in any position reduced patients’ pain by 30 percent. This was true even when tape was just placed across the patella. The specific taping method used most often for PFPS was no better than tape just slapped across the kneecap.

Taping the patella does seem to reduce pain. We’re just not sure how. The authors conclude that taping probably doesn’t work by changing the position of the patella. There must be some other reason.

Here’s good news if you’re someone who likes to get things over with quickly. Total knee replacements can be done two-at-a-time. It’s called bilateral total knee arthroplasty. Instead of having one knee replaced at a time, you can do them both at once.

The up side is that there’s only one operation. This means less time under anesthesia and less total time in the hospital. In fact, fewer wound infections and less physical therapy are added plusses. There can be some problems with bilateral knee arthroplasty, however. Blood loss, early death, and increased confusion after the operation have been reported.

Researchers at the Center for Hip and Knee Surgery at St. Francis Hospital in Indiana report on the use of bilateral knee arthroplasty. They compared the results of surgery for three groups: (1) single knee replacements, (2) both knees done one at a time, and (3) both knees done at the same time.

A total of 6,200 total knee replacements were done at this hospital over a 17-year period. More than 2,000 patients had both knee joints replaced at the same time. The doctors found a higher rate of blood clots in this group compared to the group having single arthroplasties. Yet the authors of this study report that bilateral total knee arthroplasty is safe and effective. Problems such as increased skin infections and blood clots can be managed. No difference was found among the three groups for implant failure, heart problems, or death rate.

So if you’re in good health but a lot of pain, you might want to take the plunge and get both knees replaced at the same time. Your doctor will know if you are a good candidate for this method.

Unfortunately, knee joint replacement doesn’t always end knee problems. In some cases, the new knee joint doesn’t work well. It may even create new problems. Sometimes revision surgery is necessary to fix the problem. This means the surgeon fixes or replaces the artificial knee joint.

Patellofemoral (PF) problems account for about 50 percent of revision surgeries. Patellofemoral refers to the area where the patella (the kneecap) meets the femur (the thighbone).

This article sums up the most common PF problems after knee replacement surgery. It gives a history of knee joint design. Improved designs have made revision surgery much less likely over the past twenty years. The article also discusses common PF problems. The authors present ways surgeons can help prevent or fix these problems.

The authors note that good surgical technique is key to avoiding PF problems. The authors also credit better understanding of how the knee works for improving outcomes after total knee replacement.

Women athletes tear the anterior cruciate ligament (ACL) of the knee at least twice as often as men in the same sports. Much recent research has tried to figure out why. Many possible reasons have been identified. It is possible that all these factors play some part in women’s high number of ACL injuries.

These authors looked closer at the theory that women’s hormones make ACL injuries more likely. They specifically looked at a hormone called relaxin. Relaxin is only found in women. Pregnant women produce it at high levels. All women seem to produce it during a certain stage of the menstrual cycle. Research has shown that relaxin affects ligaments. It seems to affect the body’s ability to produce and repair collagen. Collagen is the rope-like tissue that forms the strands of ligaments, tendons, and other supportive tissue in the body.

In this study, the researchers studied ACL tissue from women and men undergoing ACL surgery. The tissue was tested in the laboratory to see if relaxin could attach itself to the ACL cells. As expected, the relaxin didn’t attach to any of the tissue from male ACLs. But relaxin did bind to certain types of cells in female ACL tissue.

These results proved to the authors that relaxin could be affecting women’s ACLs, making them weaker and more prone to injury. The exact way this works is not known. But the authors note that, if relaxin does cause direct damage to the ACL, all women may be at increased risk of injury. And women who use oral contraceptives might be at even higher risk for ACL problems.

Ladies and gentlemen, listen up! But especially lady athletes: research now shows that women are more likely to injure the anterior cruciate ligament (ACL) than men. In fact women are two to six times more likely to tear the ACL compared to men. This applies to all sports and activities. Basketball and soccer players have the greatest risk.

Researchers are trying to sort out the details. Is it skill level? A lack of muscle strength? Joint laxity? Alignment problems? This study looks at two things: (1) the amount of damage in the knee cartilage at the time of ACL tear, and (2) the mechanism of injury.

Researchers included athletes from all levels (high school to amateur) and all sports. Over 1,000 patients filled out a form with information about age, sex, weight, height, sport, and competition level. How the injury occurred was also included. The researchers narrowed the field down to 221 athletes (men and women). This is the first study to report differences between men and women for meniscal tears that occur at the time of ACL tear and to report sport and level of play.

The researchers found that female high school athletes playing soccer had fewer tears of the meniscus. Female basketball players had fewer injuries to the medial femoral condyle (inside edge on the bottom of the thigh bone). Comparing amateur athletes was much harder. Fewer differences were noted. Most notably there were fewer lateral (outside edge) meniscal tears in women basketball players.

The reason for these differences in high school female athletes is unclear. The authors think there must be some type of difference in mechanism. Perhaps it is from a greater outward angle of the knee in men, or it might be that there is less force because women are lighter and shorter than male athletes in the same sport.

There are lots of other factors to study, including the size of the cartilage, firing of muscles, and differences in force from muscle contraction. More research is needed before a final answer is determined.

When the anterior cruciate ligament (ACL) in the knee tears, it usually requires surgery. The torn ACL is often removed and replaced with a tendon graft from the same leg. More and more evidence says that hamstring tendon grafts are the best way to reconstruct a torn ACL. (The hamstring is the group of muscles on the back of the thigh.) Recovery seems good, and most athletes can return to their sports. However, these doctors found some patients–those who wrestled, did gymnastics, or practiced judo–who complained that their hamstrings weren’t as strong as they used to be.

So the authors decided to do more detailed tests of hamstring strength after ACL surgery. Ninety patients took part in this study. The authors divided them into two groups. One group got a tendon graft from the semitendinosus tendon of the hamstring. The other group had grafts that were taken from both the semitendinosus and the gracilis tendons. Both types of grafts are commonly used in ACL reconstruction surgery.

Thigh muscle strength and knee function was tested before surgery. The same tests were repeated at various times up to two years later. The standard tests showed good results in strength and function for both groups. However, the authors did see a difference during more in-depth testing of hamstring strength. The hamstring muscles were much weaker after surgery when the knee was deeply bent, as when squatting. The hamstring muscles that got both a semitendinosus and gracilis tendon graft were weaker than the other group. The weakness was due to the effects of taking graft material from the leg.

The authors note that both groups got good results overall. However, hamstring strength is important for knee stability and for doing certain movements. The authors believe that which graft to choose might depend on what sports the patient wants to return to. The authors are now testing whether different exercises could help strengthen the hamstring muscle after ACL reconstruction using hamstring graft tendons.

When someone tears the anterior cruciate ligament (ACL) of the knee, surgery is almost always necessary. ACL reconstruction has been proven to return people to their regular activities. Orthopedic surgeons are now trying to fine-tune their techniques to get even better results.

These authors studied the differences between using graft tendon from the hamstring (the muscles in the back of the thigh) and from the front of the knee (patellar tendon). Both types of grafts are frequently used. Both are known to give good results.

In this study, the two types of grafts were compared directly. One surgeon repaired the ACLs of 65 patients. All patients were between 18 and 40 years old. Some patients got patellar tendon grafts, and the rest got hamstring tendon grafts. The surgical procedures were as similar as possible. All patients also followed the same rehabilitation program, which involved a very gradual return to sports.

Both groups were followed for three years. X-rays, a physical exam, pain and function questions, and a check of knee flexion and extension were done at several visits over the study period. The researchers found that both types of tendon grafts gave people good function after three years. The main difference between the groups was that people who got the patellar tendon graft had more pain when they kneeled, although the pain was mild. The patellar tendon group also had more trouble fully extending their legs. On the other hand, hamstring tendon grafts were looser, although this didn’t seem to affect knee function. These results are similar to those of other studies on the two types of grafts.

Because both tendon grafts perform well, surgeons need to decide which one to use. The authors note that some surgeons might choose to specialize in one type of graft. Others might want to decide which graft type would be best for each individual patient. For example, patients who have to kneel a lot would probably do better with a hamstring tendon graft. The surgeon in this study decided to individualize treatment. This surgeon now uses hamstring grafts for two-thirds of his ACL repairs, compared to one-third at the beginning of the study.

College athletes are at high risk for tearing the anterior cruciate ligament (ACL) of the knee. This serious injury is especially common in basketball, football, and soccer players. An ACL injury usually requires surgery for the athlete to return to competition. Rehabilitation can be difficult. ACL injuries often end athletic careers.

How will an ACL injury affect a college athlete in the future? To find out, these authors sent surveys to Division 1-A athletes who had finished college two to 14 years earlier. Half of the athletes had suffered an ACL tear during college; the other half had not. They all answered questions about knee pain and function, quality of life, and their participation in sports since college.

The results showed no significant difference between the two groups. The main difference seemed to be that athletes who had injured ACLs in college had, on average, lower scores for knee function by one type of ranking. Other than that, the two groups seemed to have similar quality of life scores and seemed to participate in sports at about the same level. However, the authors note that only five of the injured athletes played professional sports, compared to 14 of the uninjured athletes.

Most of the athletes with torn ACLs had surgery. The surveys also showed no significant differences between athletes who had surgery and those who hadn’t. The authors don’t draw any conclusions about treatment from this. They didn’t ask for details about the injuries. The study was also small and involved athletes from the same college. But the results do suggest that elite college athletes are recovering quite well from ACL tears.

Doctors have options for reconstructing a torn anterior cruciate ligament (ACL). Two methods are used most often. The torn ligament can either be replaced by a graft from the patellar tendon on the front of the knee, or by agraft from the hamstring tendon on the inside edge of the knee. There are pros and cons with each method.

In the past hamstring tendon grafts were doubled over to increase their strength. In this study the tendon was quadrupled to give make it even stronger. Also, doctors used a small piece of bone attached to the tendon, called a bone plug.

Results showed that pain was higher among patients who got a patellar tendon graft, and they reported more pain with kneeling. When this method was used, most patients (80 percent) had to stay in the hospital longer than 24 hours because of pain. Otherwise there weren’t any major differences between the two groups.

The authors report a high number of athletes had good results with either method. There was one important difference. Only 60 percent of the athletes returned to their sports activity at the same level as before the injury–regardless of the graft used. This is an area for further study. The authors suggest that patients with knee straightening problems or patellar tendonitis should consider the hamstring graft instead of the patellar tendon graft.