FAQ Category: Knee

Most doctors don’t want to do a total knee replacement on middle-aged patients. The
implants are only expected to last 10 to 15 years. You may think getting a second
replacement later is all that’s needed. It’s not that simple. Sometimes ligaments are cut reducing the joint stability. Bone is lost putting the first implant in and taking it out again.

Just replacing the side of the joint that’s arthritic is a good option. This is called a
unicompartmental knee replacement (UKR). Studies show joint motion is often nearly normal after this operation. This may be because the ligaments remain intact and the
joint surfaces still match.

Cutting a wedge or pie-shaped piece of bone out of the lower leg bone (the tibia) is another option. This is called a tibial osteotomy. The result is to realign the
joint and change the angle. Less load is placed on the inner side of the joint after this operation. The long-term results of this surgery aren’t always good. After 15 years, 25 percent of the patients need another surgery.

Listen to your doctor’s advice. Find out which option he or she would recommend. This may be based on the condition of your joint as well as the surgeon’s experience with each treatment method.

As you describe it, your doctor is following the standard protocol for this type of injury. There is a new study from the University of California–Davis that might offer some hope.

They compared results in two groups after cartilage repair using microfracture.
Microfracture is the method of drilling tiny holes into the bone at the site of the injury. The idea behind this treatment is that poking holes in the bone causes bleeding. Clots form in the cartilaginous defect. Then fibrocartilage forms to fill in the holes.

The original area of injury also gets filled in.

Continuous passive motion (CPM) is used after the operation. CPM keeps the knee moving after surgery. The leg is placed inside a trough-like machine that slowly bends and straightens the knee over and over. The theory is that CPM puts pressure on the bone and stimulates bone growth.

This new study showed that patients who got up and walked right away had the same results as those who stayed in bed and used CPM. This could mean getting back on your feet sooner than later will get you on the field sooner. Follow the advice of your doctor before resuming your sport activities.

Chondral is a term used to refer to the gristle or hyaline cartilage at the end of
the bones. When the cartilage is pulled away from the bone it can leave a tiny hole or crater. This is called a chondral defect. The joint surface is disrupted and no longer smooth at the point of injury.

When the cartilage pulls away from the bone it can take a piece of the bone with it. That piece of bone is a loose body, sometimes called a knee mouse.

Cartilage can’t repair itself, and these types of injuries can lead to arthritis. Early treatment to remove the loose body and repair the joint surface is often advised.

Full-thickness cartilage tears of this type do not heal well on their own. Painful symptoms and loss of motion often occur. If there’s a piece of cartilage or bit of bone
loose in the joint, it can cause the knee to catch or lock up. The risk of further injury increases when this happens.

The problem with managing these injuries on your own is that the defect (where the cartilage and bone pulled away) tends to be a crater with deep sides. The joint cartilage
has trouble filling over the gap. Without surgical repair the joint is at risk for more damage.

The end-result can be severe arthritis with pain, loss of motion, and loss of function. Early treatment of full-thickness cartilage tears is usually advised.

Pool therapy can be very helpful in a rehab program. It unloads the joint while strengthening the muscles. The legs become nearly weightless while still getting resistance. Pool therapy helps reduce swelling while encouraging greater motion with less pain.

An underwater treadmill works best for someone who has had knee surgery. There is a down side to water therapy. The drag of water may change the way a person walks. Muscles aren’t activating the way they would on dry land so the training effect isn’t quite the
same.

There’s no harm in asking your friend to consider water therapy as an option. A doctor’s approval may be needed. Pool therapy may have to wait if there are stitches, staples, or open wounds of any kind.

Astronauts are subject to many possible problems due to travel in a gravity free
environment. Muscles start to waste away. Bones get brittle and the heart and lungs start
to get deconditioned.

Exercise in space has not been able to help staff keep muscle strength and mass.
Treadmills with bungee cords have been tried but the harness is uncomfortable. A lower
body negative pressure chamber has been devised to help with this problem.

The chamber is a rectangle-shaped box that forms a vacuum around the lower body. It’s sealed at the waist. A pecial saddle helps the legs stay relaxed while supported.
Pressure can be lowered to reduce the force on the joints equal to 20 percent of the person’s body weight.

Using this idea might be helpful with patients who need to get up and moving but can’t put weight on their leg. This could apply to patients with hip and knee surgeries, amputations, and even strokes. It’s not available for commercial use yet. It’s still being tested for patient use.

There’s much interest and debate around this topic. The materials used in a total knee replacement (TKR) are designed to give the implant movement like a normal joint. The implant is usually made of sturdy materials such as stainless steel, alloys of cobalt and chrome, and titanium. Plastic liners may be part of the implant. These are durable and wear resistant.

Orthopedic surgeons, engineers, and other scientists are working together to improve the surgery and implant materials. Right now these materials are not made to withstand the stresses of running, heavy physical work, or contact sports. Engaging in these types of activities after TKR may lead to damage or early wear of the implant. The estimated lifespan of a knee implant is 10 to 15 years.

Impact sports like running are not usually advised. No-impact or low-impact sports are acceptable. Be sure to tell your doctor your interests in activities. Sometimes the type of implant used can make a difference. Find out what to expect. Your implant last the longest if you follow your doctor’s advice.

Studies show that patient expectations before joint replacement have an impact on their
final outcome. This can work for or against the patient. Some people are just happy to
have pain relief. Others are disappointed they can’t run a marathon. There’s a wide range
of expectations and results in between.

There are many factors to consider. First, what was your mother’s activity level before
her knee became painful enough to need a replacement? How much time has passed from when
she was active to now? What is your mother’s activity level at this time (just before
surgery)? If she’s inactive, has she lost overall strength and flexibility?

Many surgeons advise the patients who are getting knee replacements to expect pain relief
and improved function. They will likely be able to walk, swim, or ride a stationary bike
if they are in good health and physically fit.

Activities that put a higher demand on the knee joint are not as easy. This may include
running, twisting, dancing, stooping, and squatting. Encourage your mother to ask her
doctor what to expect and how soon to expect it after surgery.

Stretching is safe and encouraged. Stretching helps keep the muscles around the joint flexible. This is important for getting your motion back and for performing daily activities. It also helps should you twist or turn suddenly or lose your balance.

Most rehab programs following a total knee replacement include a series of stretches for
the whole leg from the hip to the ankle. Many surgeons have their patients begin
stretching the first day after the operation. You can continue with these as long as you
are comfortable and not having any problems.

It’s also important to strengthen the muscles around the hip, knee, and ankle. These exercises progress as you gain strength. The exercises you will do will change a week, month, or year after the operation. Usually a physical therapist will help you find just the right exercise program. This is based on your age, fitness level, type of surgery, personal goals, and length of time since the operation.

Some people consider this a “design flaw” in the human body. Cartilage anywhere in the body doesn’t have a big blood supply. We say it’s not highly vascularized. This means when it’s injured or damaged in anyway it heals very slowly or not at all.

The cartilage doesn’t have a way to heal itself. The result is often worse symptoms for the patient and joint degeneration. Surgery is done to repair the damage and bring blood to the area to speed up the healing cycle.

Cartilage has several layers. The deepest layer just before the bone is called the tide mark. Just below the tide mark layer are stem cells that can grow into fibrocartilage. This kind of cartilage isn’t exactly the same as the cartilage on the surface of the joint, but it’s better than nothing!

Right now the standard rehab after microfracture for full-thickness cartilage tears is to avoid weight-bearing and use continuous passive motion (CPM). CPM uses a device to slowly move the knee through its range of motion. It’s usually used for six to eight hours a day for up to eight weeks after microfracture.

Microfracture is one way to enhance healing. Tiny holes are made in the bone just beneath the cartilage. Fibrocartilage fills in where the cartilage is torn and pulled away from the bone.

Researchers are calling the standard rehab procedure into question. Studies show no difference in results with or without the use of CPM. Likewise, putting weight on the leg isn’t a problem either. Up until now the theory was that pressure through the joint would disrupt the healing process.

Ask your doctor to review the latest studies on this rehab method. With close supervision you may be able to bypass the six weeks’ restriction and return to sports sooner.

The meniscus in the knee joint is divided into two parts. Both are horseshoe or C-shaped and present on the inner and outer sides of the joint. The inner half is called the medical meniscus. The outer half is called the lateral meniscus.

In the past studies showed worse results with medial meniscal tears. But a recent review of 25 studies done between 1966 and 2003 showed only one out of six studies support this finding. Overall there were no big differences in the X-rays or patient function after either type of meniscectomy.

It looks like other factors are more important than which side was injured. For example, women have a higher rate of arthritic changes after damage to the meniscus. The amount of damage to the meniscus also makes a difference. A severe tear has a poorer result than a minor tear.

Finally, arthritic changes that are present in the joint before the tear are also linked with worse results later. X-ray studies before and after meniscal repair have brought this finding to light.

The diagnosis of a meniscal tear is often made based on the history and pain pattern. A physician can also use special tests on the knee. Stress and movement of the knee joint can make the meniscal tear snap or cause pain. This sign helps confirm the diagnosis.

An MRI scan can be used to see the meniscus and the condition it’s in. A good MRI scanner has a very high accuracy rate. It can show clearly when a tear is present or when a piece of meniscus is missing.

MRIs aren’t used routinely because of the cost. If the clinical exam is positive, then arthroscopic surgery is often indicated anyway. Some MRI findings such as degeneration of
the cartilage common with aging doesn’t necessarily mean surgery is needed.

Researchers do try to find ways to tell how much recovery might occur after illnesses and injuries. This kind of information can help doctors advise and direct their patients. A recent study from the Harvard Medical School offers some new information about meniscal tears of the knee.

They reviewed the results of 25 studies. They found patients had the worst outcomes when they were in poor health or in a legal battle over the accident. Other factors pointing to a worse result included prior surgery on that knee and a large-sized tear. Patients with osteoarthritis of the knee before the tear showed greater X-ray changes in the joint later.

Any of these variables can mean more pain and less function down the road. The surgeon can give you a better idea of your odds after looking inside the joint and viewing the damage with an arthroscope.

The cost of new ideas and ways of doing things based on improved technology probably does raise the cost at first. In theory, the idea is to gain a higher degree of control when doing surgery.

The surgeon will make fewer errors. The patient will get better joint alignment and function. There will be fewer failed implants. The patient will be more satisfied. Second (and third) operations after the first won’t be needed.

The operation can be done in less time. The surgeon won’t need another surgeon to assist in the operation. Rehab can begin sooner. All of these various factors have the potential to save money in the long run. We won’t know for sure until results are ready from studies done over five years, 10 years, and longer.

Like most advances in medicine, the cost goes down the longer it’s been in use.

Many studies support the use of the unicompartmental knee arthroplasty (UKA). It’s been shown to have a faster rehab time, give better function, and cost less than a total knee replacement.

Failure in a small number of cases does occur. There are several reasons why this can happen. Sometimes the arthritis continues to get worse. The bone around the implant wears away and the implant loosens.

n other patients the hip, knee, and ankle don’t line up as well as they used to. Finally, overcorrecting a deformity at the time of surgery can cause too much load on the knee joint. The wear and tear on bone and ligaments can lead to failure of the implant.

It may still be possible to salvage your “new” knee. Sometimes surgery to revise the implant is the answer. In other cases, replacing the unicompartmental implant with a total knee replacement is the next step. Be sure and ask your doctor what are your options. Perhaps get a second opinion from another surgeon.

You may be having symptoms of a problem called patellofemoral pain syndrome (PFPS). PFPS can occur when the kneecap rubs against the femur (thigh bone) as it moves up and down with knee motion.

Sometimes the patella, or kneecap, gets out of the groove it normally glides in. Abnormal positioning of the patella leads to inflammation and pain. This problem can get started by muscle imbalance, inflexibility, changes in the bones, improper walking pattern, overuse, or trauma.

There are many ways to treat PFPS. Consult with a physical therapist or orthopedic surgeon for a proper diagnosis. The best treatment plan depends on the exact cause of the symptoms.

There are two symptoms most common with PFPS. Often there is pain with prolonged sitting. When the knee is straightened a painful pop occurs. This is referred to as the movie-goers sign. With PFPS, there is usually no swelling or just a small amount of swelling. A large amount of swelling points to some other cause of the pain.

The second symptom often reported by patients with PFPS is pain going up and down stairs and hills.

If your symptoms don’t get better gradually with rest, ice, and elevation, it may be a good idea to see a doctor who can diagnose the real cause of your problem. Early treatment can help prevent worse problems later with many knee conditions.

Taping the kneecap in place is often suggested as a treatment method for patellofemoral pain syndrome (PFPS). This helps keep the kneecap (patella) in good alignment as it moves up and down.

Many studies have been done to see if taping works for PFPS. Some show no effect while many others say taping reduces pain right away. Still other research shows taping works no matter how it’s applied.

This last finding suggests it’s not the position of the patella (knee cap) that makes a difference. Perhaps the taping improves the patellofemoral joint position sense called proprioception. Or maybe it helps the muscle contract more fully pulling the kneecap back into proper alignment.

If taping doesn’t work, there are other treatment choices that can be tried.

Acupuncture has been used in China for 5000 years to relieve pain and treat a variety of chronic, acute, and degenerative conditions. It remains the standard treatment of osteoarthritis in most Asian countries.

Acupuncture is gaining in popularity among Americans too. Over one million people use
acupuncture in the United States each year. Studies are showing it is effective as an alternative form of treatment.

Acupuncture doesn’t work for everyone. Best results are seen when it’s used early in the course of knee arthritis. Patients report less pain and more mobility. For some patients
acupuncture decreases the pain enough to help them reduce their dependency on pain-killers.