FAQ Category: Knee

LCS stands for Low Contact Stress mobile-bearing knee replacement. It has a unique design that has shown long-lasting wear capacity. A mobile-bearing total knee replacement (TKR) is different from the standard TKR.

It allows for a small amount of rotation in the joint as the knee bends and straightens. This is needed in order to mimic normal motion. It helps prevent uneven wear on the joint.

The mobile-bearing TKR also puts less stress on the polyethylene (plastic) liner. In all TKRs, the lower portion of the prosthesis is attached to the tibia (lower leg bone).

In many TKRs, the lower portion of the implant is fixed and doesn’t move. This puts extra stress on the polyethylene (plastic) liner or spacer. With the LCS, the spacer between the tibia and femur (thigh bone) rotates with the femoral (upper) part of the TKR. The reduced stress results in less wear and fewer fractures.

If there are bony or soft tissue imbalances that are not corrected when the TKR goes in, then uneven wear or increased loads can lead to fracture of the liner. Even mild changes in the angle of the joint (called varus or valgus) can increase the risk of subluxation, dislocation, or fracture.

With the LCS, bearing fractures occur most often when the knee is bending while the bearing is subluxed posteriorly. This means the liner slips backwards. It moves just enough that the contact points for the implant and liner change. The result can be stress that eventually fractures the plastic spacer.

Knee replacements, called total knee arthroplasties are not as old as hip replacements. It appears that the first knee replacements were attempted in the 1960s were did not have a good success rate until the 1970s. Now, the rate of knee replacements performed yearly is drastically rising. There was over a 400 percent increase in TKAs done in the years 2000 to 2003 over those done in a similar length of time in the 1970s.

A knee replacement, called a total knee arthroplasty is more complicated than a hip replacement, or arthroplasty. The hip bone is a ball and socket type of joint, but the knee joint is more complicated.

The implant for the knee has to be able to withstand the force on the knee, as well as the ligaments and muscles pulling from three different directions.

Tuberculosis (TB) is most commonly a respiratory disease, a disease of the lungs. It is spread through droplets in the air; someone with TB coughs or sneezes, for example, someone else breathes in the virus and the TB settles in the lungs.

Once the TB virus has settled in the lungs, it can travel to other parts of the body, through the blood, and settle in the bones. One thing to keep in mind is that TB in a bone is not usually contagious.

TB of the knee shows up as pain and swelling, making it hard to bear weight and resulting in a limp.

Recovery following a revision of a total knee arthroplasty (TKA) or knee replacement, greatly varies. It depends entirely on what the revision was for, what revision was done, and the individual patient.

Of course, there is the usual recovery time of having undergone a surgery requiring a general anesthetic; this means taking care of the wound and the dressing, your respiratory status – making sure you have cleared all the anesthetic out of your lungs, and your mobility.

Whether you need to begin with the basics of moving around again or can move ahead quickly will be decided upon by your doctor and physiotherapist.

Arthro refers to any joint. Fibrosis is scar tissue or adhesions. Arthrofibrosis of the knee occurs most often after a knee injury or knee surgery.

It is characterized by a loss of motion called a joint contracture. The extent of the problem is defined by the severity of the contracture. There can be a loss of both knee flexion and extension.

Most people can get along fine with a small loss of flexion. Deep squatting or full kneeling may be a problem. Loss of full extension is much more problematic, especially for the athlete. Even a small amount of extension loss can cause a limp and knee pain.

Arthrofibrosis can be mild to severe. It can range from a local problem in one area of the joint to all compartments of the knee. In more involved cases, even the soft tissues and muscles around the knee can be affected.

Loss of motion with knee arthrofibrosis is the most severe after a high-energy injury that tears or ruptures more than one ligament. Low-energy, single-ligament trauma is usually less severe in its consequences.

Motion is lotion and is the first line of defense to prevent arthrofibrosis after knee injury and/or surgery such as an ACL repair. Surgery may be needed to manipulate the knee and remove the adhesions. The procedure must be done with care to avoid damage to the bone, tendon rupture, or fracture of the patella (knee cap).

The use of a rehabilitation brace after ACL reconstruction is a topic of ongoing debate and discussion. At the present time, bracing after ACL repair is common. A recent survey showed that 85 per cent of surgeons used bracing for their ACL patients. Bracing is used an average of four weeks after the operation.

Some new studies have shown that bracing isn’t needed, while others report bracing for at least three weeks helps prevent loss of knee extension.

With or without bracing, some patients develop enough scarring to cause loss of motion, a condition called arthrofibrosis. Significant loss of flexion or extension may require surgical intervention. Manipulation is the moving of a joint through its full motion while the patient is anesthetized.

Manipulation under anesthesia is done with the aid of an arthroscope. This device makes it possible for the surgeon to see inside the joint during the procedure. Using this technique, any nodules or loose fragments of cartilage or other tissue can be seen and removed. This process is called debridement.

The surgeon can determine how much of the joint is involved. The exact location of the problem can also be identified. This makes for more accurate and successful treatment with fewer problems afterwards.

Arthroscopic manipulation and debridement can be a very successful operation. Restoration of full and normal motion is the ideal outcome. In cases of severe arthrofibrosis, multiple surgical procedures are sometimes needed.

With the right donor tissue, the risk of infection is very low. Your surgeon should be using tissue only from AATB-accredited tissue banks. AATB stands for American Association of Tissue Banks. They have the highest standards for selection, storage, and processing of donor tissue.

One member of the AATB has had no confirmed reports of infection for more than two million units of allograft tissue. This not-for-profit group is the Musculoskeletal Transplant Foundation (MTF).

Allograft refers to tissue donated by someone other than the patient. Autograft is tissue taken from some other part of the patient’s own body and then used to repair or reconstruct the same patient’s damaged tissue.

New and improved testing is also available for infections such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV). Instead of looking for antibodies to these viruses, nucleic acid testing can be used to look for the virus directly.

There is also a risk for bacterial infection. One donor can supply tissue for many, many patients. Unless the allograft is properly prepared, they are all at risk for infections.

Tissue that isn’t collected or refrigerated soon enough is at risk for bacterial infection. Proper sterilization methods must also be used to avoid various kinds of bacterial growth.

Tears of the meniscus in the knee are common among sports athletes, especially football players. It’s true that the standard of care for meniscal tears has changed. This is based on long-term studies of what happens to these athletes 10, 20, or even 30 years later.

It was once thought that the meniscus wasn’t really needed. Tears causing pain or loss of motion led to surgery to remove the cartilage. Now we know that the meniscus provides mechanical support to the knee. It evens out the pressure and load in the joint. At the same time, it helps keep the joint lubricated.

Along with a better understanding of the function of the meniscus has come advances in surgical technique. Instead of an open incision, the meniscus is repaired arthroscopically. This allows more of the meniscus to be kept intact.

A thin needle is inserted into the joint through a small puncture hole. A tiny TV camera on the end of the scope allows the surgeon to see inside the joint. The tear ir repaired or the fragment that can’t be repaired is removed.

It’s true the players’ time on the field may be decreased with multiple revision surgeries. But the individual is spared the long-term consequences of a missing meniscus. Disabling arthritis and an eventual total joint replacement may be avoided. Repairing each meniscal tear instead of taking the cartilage out improves short-term function and long-term outcomes.

When surgeons began doing knee arthroplasties, or replacements, the surgeries were done by replacing the whole knee. While quite successful, surgeons and researchers learned that replacing the whole knee wasn’t always necessary since it wasn’t always the whole knee that was damaged.

surgery for a partial knee replacement, also called a unicompartmental arthroplasty is not as invasive as a total replacement, and usually requires a smaller incision and shorter recovery time. Therefore, if it is possible to do a partial replacement, this would be preferable in many cases.

Usually, the most ideal patients for a partial replacement are those who are not obese, whose cartilage (tissue attaching muscle to bone) are intact, and who have damage limited to one area of the knee.

There are many types of implants a doctor can choose from when performing replacement surgery. There are usually many factors that are involved in making the choice as to which one to use. For example, the condition of the bones, the type of activity the patient does, what type of damage has been done, what implants are actually available, cost, and the doctor’s experience with the implants.

Certain types of implants have advantages over others, depending on several things. If a patient wants to know more about the type of implant being used, it’s best to speak with the surgeon and to ask questions about the implant, the surgery, and the reasons behind everything that is being done.

The choice of implants the doctor makes is based on several factors and even though both of your knees may need to be replaced, they may not have the same problems or the extent of the problem may differ. Therefore, it is entirely possible to have two implants that are different.

Joint replacements are becoming more common as the population ages. It used to be that hips and knees were only replaced in older people. The actual joint mechanism and materials used have a certain life span. If a particular joint has a lifespan of 15 years, an implant in someone who is 70 years old should be ok until that person is 85, for example.

Because of this limited lifespan of the hardware, doctors have been reluctant to use replacements in younger patients, particularly those under 55 years old. They feared that the rate of surgery to fix or replace the replacements would increase dramatically, and that the more active lifestyle of the younger patient would put added stress on the replacements, causing more problems with the hardware.

Research is showing that certain types of replacements do do well in younger patients and that the replacements are a better option for some. Because of this, more doctors are performing more replacements in younger patients.

When a knee or hip has been replaced, there may be some issues that need to be corrected later on. In some cases, the hardware itself may break down or wear out, in other cases, the bones around the hardware may be causing some problems.

A revision surgery may be done if there is an infection in the joint, if the bones are wearing down or if the joint needs to be repaired or replaced.

Revisions of total knee arthroplasty (TKA), or knee replacement, can be necessary for several reasons. If the problem is with the mechanics of the actual implant, perhaps some loosening, this surgery is likely possible just to be a repair job, rather than a full replacement.

However, if the implant is grossly damaged or defective, or if the patient has experienced trauma or deterioration of the bone, a full replacement may be needed. If the bone has deteriorated, the patient may require a different type of implant, allowing the knee to function again. For this reason, a repair wouldn’t be possible.

The only way to repair a torn meniscus is by doing surgery. But not everyone with a meniscal tear needs surgery. In fact, there are many people out there with tears in one or both menisci who don’t even know they have them. MRIs frequently show up meniscal tears in patients who have no symptoms.

But when pain, swelling, knee locking, and loss of motion affect function, then surgery to repair or remove the fragment is advised. It is also suggested that before resorting to surgery, conservative care can be tried.

Older adults or even younger adults who are not involved in sports may benefit from activity modifications, nonsteroidal medications, and physical therapy.

The physical therapist can address postural or alignment issues that may be contributing to uneven wear and tear on the meniscus. A program of strengthening exercises can also help reduce limitations and improve function.

Ask your doctor to take a look at your knee and make his or her best recommendations. Explore all nonsurgical options first. Surgery is an option if you are still unable to participate fully in daily activities, work, recreation, or sports.

Enough studies have been done now on the use of chondroitin sulfate (CS) and glucosamine (GS) to show us some trends. First, it looks like these products are safe, even if they don’t work for everyone.

Second, it appears that many patients do experience pain relief and improved function from taking these products. A study sponsored by the National Institutes of Health (NIH) has shed some important light on these supplements.

The study called Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT) looked at CS alone, glucosamine alone, and the two combined together. They used products that met certain standards otherwise set for drugs.

The results of the GAIT study showed that CS works better when it’s combined with glucosamine. The pharmaceutical-grade supplement used most often in Europe is called Cosamin.

But all the evidence isn’t overwhelming in its support of these products. Researchers say the results are at a medium level. This means further study may show different results.

Right now the opinions are split on taking CS and/or GS for arthritis. The European League Against Rheumatism strongly recommends these products. The American College of Rheumatology says the evidence is too weak to recommend their use.

The Agency for Healthcare Research and Quality specifically recommends the use of a CS/GS combination instead of an antiinflammatory drug. They make this suggestion for patients with moderate to severe arthritis pain.

It’s always a good idea to check with your doctor before taking any product. This is especially true for CS/GS, which is an unregulated, over-the-counter supplement. Your health, current use of other medications, or other factors may be important factors.

Your orthopedic surgeon is going to be the best one to answer this question. Recovery depends in part on the general health of the patient. Preoperative range of motion and strength will be key factors in postoperative recovery rates. Tobacco use and poor nutrition can delay wound healing.

The type and extent of surgery can also make a difference. The surgery may be done with an open incision or minimally invasive arthroscopic surgery may be possible. Open incision cuts through more soft tissue and possibly muscle causing a longer recovery and rehab time compared to a minimally invasive procedure.

You will likely be placed in a knee immobilizer right after surgery. You’ll be started on quadriceps strengthening exercises. You can do these with the immobilizer in place. Passive and active range of motion exercises are begun within a few days of the operation.

If all goes as planned, you’ll probably be allowed to put weight on the leg by the end of the first week. The surgeon may switch you from the knee immobilizer to a patellar brace for this. By the end of the second week, you’ll be able to put your full weight on that side.

Your program of exercises will be progressed gradually. Full rehab takes at least three months. At first you will work with a physical therapist. But over time, you’ll be able to do more and more on your own. The therapist will gear your program around your specific sport of skating. Many athletes are able to return to their sporting event at approximately three months after the operation.

You’ll need to see an orthopedic surgeon to assess the problem. Your age, general health, and activity level will be taken into consideration. Tests will be done on your knee and X-rays will be taken.

Once this information has been collected, the surgeon will be able to advise you. Sometimes a rehab program can restore normal biomechanics and balance strength. The result is a stable knee that doesn’t dislocate with normal, everyday activities.

But if the soft tissues around the knee are damaged from the repeated trauma of dislocation, then surgery may be needed to gain permanent stability. There are many different surgical procedures for this problem.

The medial patellofemoral ligament (MPFL) is the main soft tissue that holds the patella (knee cap) in place. An overly tight band of tissue along the outside edge of the patella can also pull the knee cap over. This band is called the lateral retinaculum.

Surgery usually addresses both of these problems. The lateral retinaculum may be released (if too tight). The MPFL can be reconstructed and realigned to balance the patella and prevent future dislocations.

It’s important to get the right amount of tension between these two soft tissue structures. Too much tension on the MPFL can put pressure on the patella and cause patellofemoral osteoarthritis (OA). Surgeons are working hard to find the best method to prevent both problems of recurrent dislocations and the development of OA after surgery.

More and more surgeons are now using the minimally invasive surgery (MIS) for unicompartmental (one side) and total knee replacements (TKRs). This new technique has been made possible by advances in technology and surgical instruments.

The MIS method was actually developed for unicompartmental knee arthroplasty (UKA). It was later adapted for use with TKRs. With MIS, there is the obvious advantage of a smaller scar for the patient. But this also means less soft tissue and muscle is cut making rehab and recovery faster and easier.

Other advantages of the MIS are less blood loss, less pain, and lower costs. There are some concerns about the accuracy of implant position with a shorter incision. But improved computer navigation may offset this problem.

So far, several studies have shown no difference in the accuracy of implant alignment between these two surgical procedures. It’s likely that more and more surgeons will move from the traditional open incision method to the MIS method.