FAQ Category: Knee

The use of antibiotics mixed with cement for total joint replacements has been around for over 30 years. Some doctors use this with every patient. Others reserve its use for joint infections or failed first operations.

A group of doctors at NYU (New York University) reviewed all of the studies done on this topic. They found that there isn’t one method used and approved by all doctors. The FDA (Food and Drug Association) doesn’t take a stand on the use of antibiotics in cement.

It’s only experimental in that researchers continue to study the problem. They are looking for a product that can be mixed into the cement without changing the cement’s strength. Future cements with drugs mixed in will have a slow release of the antibiotic. This will help lower the infection rate, too.

There are two major ligaments in the knee joint: the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). By far, the ACL is injured or damaged more often than the PCL. Not as much is known about what happens when the PCL is torn.

A recent study in Germany tracked 181 patients with PCL tears who did not have surgery to repair the injury. They found that damage to the joint cartilage after a PCL tear is common. In fact, more than half of all patients with a PCL tear develop cartilage damage and arthritis after that.

After a PCL tear, there is a change in where the knee joint comes together during movement. A weak PCL causes more pressure on the inside edge of the knee. Higher loads and greater force act on the cartilage. The cartilage gets worn down and damaged.

Yes, it is possible. However, more and more studies show that ligament tears without repair cause further joint damage over time. Without the ligament to hold and guide the joint, increased loads are placed on the knee. Within a year, changes in cartilage are seen on arthroscopic exam.

After five years, almost 80 per cent of all patients with an unrepaired PCL have wear and tear in the cartilage. The result is early arthritis of the joint.

The decision to hold off on surgery is best made with your doctor. It depends on the severity of the injury and extent of damage to the nearby tissues. Surgery is advised when there is a moderate to severe injury to the PCL along with a tear to the meniscus.

The posterior cruciate ligament (PCL) is one of the major ligaments inside the knee. It helps hold the knee joint steady during motion so that the thighbone and lower leg bone move and glide without shifting.

Ligaments are not very elastic. When they are torn or damaged, they don’t “spring” back. Instead, scar tissue fills in the torn area and weakness occurs. This loss of strength is called PCL insufficiency. The ligament is unable to do its job to move, hold, and protect the joint.

Blood clots or deep venous thrombosis (DVT) is very common after knee surgery. In fact, without some form of prevention, up to 84 percent of all patients develop DVT. DVT are dangerous because they can break off from the blood vessel wall and travel to the lungs or brain.

Studies show that compression pumps work well to prevent blood clots. These are favored over drugs because there are no side effects with them. There is a new device that has been developed for patient comfort and ease of use. It’s called the PlexiPulse® foot pump. This pump produces a burst of air with enough pressure to move blood from the foot into the calf. In a study at Cornell Medical College in New York, doctors, nurses, and patients rated it highly.

Your mother may be wearing a device called a pneumatic compression pump. These are placed on the legs to help blood keep from pooling and forming blood clots. The pump contracts on and off giving the leg a mini-massage.

These devices are taken off when the patient exercises or walks. However, it’s very important that they are put back on when the patient returns to bed. The compression pump only works when it’s used. Don’t hesitate to ask the nurse or physical therapist how to put them on your mother.

A ganglion cyst is a fluid-filled sac near a joint. The fluid from inside the joint leaks out through a channel and forms a pocket or cyst. This condition is slightly more common in men than women, but any adult can have a ganglion cyst.

The exact cause of the problem isn’t known yet. In the knee, it may start to form after the meniscus is torn or damaged. It does seem to be more common in middle-aged adults.

Ganglion cysts occur most often in the arms, especially the wrist. They can occur in the spine, hip, knee, ankle, and foot, too. Doctors think that damage to the area or a break down of tissue gives rise to these cysts.

In the lower leg, two bones join together just below the knee and at the ankle. These are the tibia and the fibula. A tibiofibular joint ganglion cyst describes your condition.

The cyst is a small sac-like structure that fills with fluid. The fluid usually comes from the nearby joint. Until recently, no one knew how common these are in the lower leg.

Now, thanks to a group of doctors in Texas, we know that less than 1 per cent of the adult population has this type of cyst. These doctors reviewed 654 knee-MRIs over a six-month period and found 5 tibiofibular ganglion cysts. More studies with a larger number of patients are needed to confirm this figure.

You may have a condition called bipartite patella. This is a failure of the kneecap to harden into bone during the early years of childhood. This happens in about two to six percent of children in the U.S.

Most of the time, a bipartite patella isn’t a problem. However, the cartilage has a limited ability to heal and it’s easily injured. Falling on the knee can cause a painful separation that doesn’t heal properly. With proper medical treatment, you should be able to return to sports.

Bipartite patella is a failure of the kneecap to harden after birth. This can happen to boys or girls, but is fairly uncommon. Symptoms range from mild discomfort to severe pain. Motion may be normal and the knee joint is usually stable. Swelling may occur and some patients describe a “catching” sensation.

Treatment begins with drugs for inflammation. If these don’t help, a local steroid injection may be tried. A decrease in activity is advised for up to three months. Sometimes, a cast is used to immobilize the knee. Rest from movement may help it heal.

If an injury to the bipartite patella doesn’t heal, surgery may be needed. The doctor can remove one or more pieces of the cartilage and smooth out the remaining section.

The patella is a medical term for kneecap. Bipartite means it is in two parts or sections. At birth, the normal patella is made up of a thick piece of cartilage. As the child grows, it starts to harden from the center out toward the edges.

If this fusion doesn’t happen, the patella remains in two or more sections. This is called a bipartite patella.

Yes, this is true for all women’s sports that stress the knee. Certain force patterns result in knee ligament injury. A recent report noted that ACL injury is more frequent in women skiers. One difference is that medial ligament injuries in women skiers are less severe than in other sports.

There are no reports yet to tell us how common combined ligament injuries are in skiers. Studies so far don’t show that ACL and medial collateral ligament tears together are increased among female skiers.

The anterior cruciate ligament (ACL) in the knee is made up of many fibers together inside tiny bundles. These bundles aren’t separate from each other, but they do have different jobs. Each bundle is called upon to exert its force during knee motion.

Other structures in the knee also work together with the ACL to move and protect the joint. For example, the medial collateral ligament on the inside of the knee joint keeps the knee from moving too far in a sideways direction.

The fibrous tissue of the joint capsule helps hold the joint together. Muscles around the knee reinforce the capsular tissue. This is another way the body protects and helps the ACL do its job.

The ACL can fail depending on the force placed upon it and the position of the knee. Even though the ACL has some “give” to it, too much force in the wrong direction against it can cause damage and injury. For example, during downhill skiing, if a skier loses control of his or her balance, the skier’s weight shifts backward. The ski edge gets fixed in the snow as the skier continues to move forward. There is increased force across the knee.

If the ski doesn’t come lose and the bindings hold without releasing, the force can cause a ligament to tear or a bone to break. Even the best biology has its limits.

Six months after an ACL repair is about the time most people start to see a return to more normal function. Of course, this depends on the patient’s age, overall health, and physical condition.

You should be seeing a gradual improvement in strength and motion. If not, you may have left out an important part of the rehab process. A physical therapist can help you sort this out.

The numbness is not uncommon. Almost all patients have some amount of numbness. This is because the nerve below the kneecap isn’t in the same place for everyone. There’s great variation in the location of the branches off the main nerve. In order to complete the surgery, doctors must cut through this area.

The loss of sensation is most likely going to be permanent. After 18 months, any changes in sensation are probably permanent. This damage doesn’t affect the function of your knee. It’s just annoying to many people.

If the ligament is only partially torn, a rehab program of specific exercises may be all that’s needed. A large or complete tear (rupture) leaves the knee weak and at risk for reinjury. Surgery to repair the damage is usually a good idea in these cases.

For the patient with an unstable knee, surgery is often advised. Knee instability can be measured by how much the lower leg bone slides forward from the upper leg bone. This is called joint laxity. The doctor has several ways to measure this.

One other reason patients opt to have the surgery is in order to return to preinjury level of activity. This is especially important in the area of athletics. In all cases, the soon the ACL is repaired after injury, the better the result.

The two sources of tissue for this operation come from the patellar tendon just below the kneecap and the hamstrings tendon behind the knee. According to current studies, these two methods have equal results. This refers to function and using the leg, strength and stability, and changes seen on X-rays.

As with all operations, there are always possible risks and problems that can develop. Using the patellar-bone graft can cause pain under the kneecap. There may also be weakness of the quadriceps muscle along the front of the thigh and possible fracture of the kneecap.

Using the hamstrings graft leaves the joint less stable compared to the patellar tendon graft. The graft may not take right away so that it doesn’t stick to the bone right away. This can become a problem needing more surgery.

This is a good question. Much research has been done on the topic, but not all studies use the same measurements. Different sporting events have been studied using different muscles and measures.

For example, a study in Belgium focused on professional soccer players. The authors of this study defined “tight” as less than 90-degrees of hip flexion. This was measured with the player on his back with the legs straight. One foot and leg was then lifted off the table as far as possible and the angle of hip flexion measured.

The knee stayed straight throughout the motion. As soon as the knee started to bend, the hip motion was measured. In this study, anything less than 90-degrees was considered “tight.” Other studies measure the length of the hamstrings slightly differently.

Patients who report squeaking, creaking, and other noise after a TKR may have a problem with the kneecap. The physician can diagnose this. An exam and X-ray will be needed.

Failure of the kneecap isn’t an uncommon problem. The backing can wear away and the pegs that hold it in place can break. Sometimes the plastic lining pulls away. A second operation to repair or revise this problem may be advised.

There are several possible reasons why the kneecap portion of your total knee replacement (TKR) has gone bad. The lining behind it may have cracked or worn away. The pegs holding it in place may be broken.

The doctor will need to look inside the joint to see what’s going on. Loose fragments of bone, cartilage, or the implant will be removed. Sometimes, the lining of the joint, called the synovium must be cut or removed.

The doctor will look at the implant and the joint surface for any defects or problems. Knee motion and implant alignment will be checked. The kneecap should move up and down along a track as the knee bends and straightens. A decision about what to do will be made on the basis of these findings. The replacement kneecap may be fixed or replaced again.

An orthopedic doctor can best answer this question. The removal of the kneecap or patella is called patellectomy. Replacing the patella is optional and not always advised. There can be problems with the plastic implant interfacing with bone. No one really knows how long these replacement parts last.

However, newer and better implants and improved surgery makes a patellar implant possible. See your doctor for an exam to answer this question.