FAQ Category: Knee

Small areas of damage to the cartilage in the knee joint have a limited ability to fill in with fibrocartilage. Complete and normal healing is not likely. Areas of full-thickness lesions larger than two centimeters by two centimeters (two centimeters squared) are not likely to heal without treatment.

Treatment today involves several techniques designed to stimulate bone marrow to make a clot. With multiple fibrin clots, a small defect in the cartilage can fill in and replace normal cartilage with similar cartilage.

One of those techniques is called microfracture. Another is autologous chondrocyte implantation (ACI). The microfracture procedure is done in one step. Tiny holes are drilled around and through the cartilage defect. Blood and fat cells from the bone marrow migrate into the area of the lesion and begin a healing process.

ACI is a two-stage operation. Healthy cartilage is harvested from the patient and placed in a special solution. After several hours, the cells are washed and mixed with a small amount of the patient’s blood serum. This is allowed to sit in the lab for several weeks while the cells multiply.

When the cells have increased 20 to 30 times, then the new chondrocytes are injected into the lesion. Special steps are taken to prepare the damaged area first before implantation.

These techniques are fairly new. No long-term studies have been done to show what happens years after the surgery is done. Short- to mid-term studies show good results. Some surgeons prefer the microfracture approach to ACI because of the difference in cost, technical difficulty, and extra surgery of ACI.

Scientists have used a wide variety of motion capture methods to discover these altered patterns of motion after ACL rupture and reconstruction. The study of alterations in joint motion is referred to as kinematics.

Dynamic imaging such as high-speed X-rays, fluoroscopy, or MRIs taken while the patient is moving have been used in these studies. The information gathered has helped us understand changes in knematics after ACL injury.

Changes in the contact patterns of the joint seem to be what leads to arthritis later. The cartilage cells try to adapt to changes in their metabolism from these new loads.

Studies at the cellular level show that tissue stress affects the organization of cartilage. The cartilage reacts and adapts to changes in load as much as possible. But they may not be able to withstand compressive or shear forces.

The average patient doesn’t have access to such study methods. You may not be aware of changes going on in your knee until pain, stiffness, or swelling occur. Until further studies offer specific solutions, experts advise staying active and keeping up on strength training of the muscles around the knee.

There are some studies that support this idea. Athletes who have had a complete rupture of the anterior cruciate ligament (ACL) do seem to be at increased risk for early knee arthritis. And this seems to affect those who have had surgery to repair the torn ACL as well as those who haven’t had the operation.

Animal studies have given some insight into this relationship. It seems that the cartilage in the knee is responsive to load and compression. Without just the right amount of mechanical pressure, the cartilage starts to thin out.

At the same time, changes in loads on the joint seem to set up a biologic response in the chondrocytes (cartilage cells). Chondrocytes change their volume (size) when under pressure. The wrong kind of pressure can change the fluid flow in and around the chondrocytes.

Metabolic changes at the cellular level starts a cascade of events that can lead to early destruction of the joint. Altered motion after ACL injury is the first step in the sequence.

Understanding these steps in how OA gets started after ACL injury may help us find ways to prevent it from happening. Restoring full and normal motion after ACL reconstruction will be the focus of future studies.

It sounds like your joint still has some instability. Under the right circumstances or conditions, it gives way or buckles. This may be a sign that you need to continue your rehab program indefinitely. This is especially true if you don’t ever plan on having reconstructive surgery.

A home exercise program (HEP) can be very successful in stabilizing the knee when there is an ACL tear but no other ligament, cartilage, or joint injuries. Usually the HEP is a continuation of the exercises done in rehab.

But muscle strengthening, cardiovascular training, agility drills don’t always improve knee stability. You may need to carry out perturbation-enhancement exercises. This is a way to restore joint proprioception (sense of position) and quick response to changes in joint position.

Perturbation-enhancement rehab can help the athlete resume pivoting, cutting, and jumping activities without fear of buckling or instability. If you worked with a physical therapist during the first phase of rehab, you may want to contact him or her about adding this key feature to your HEP.

According to a 10-year study at the University of Delaware, hopping tests are actually a good way to assess dynamic knee stability. When combined with other tests, patients and surgeons can be guided in making the rehab-versus-surgery decision.

Some hop tests work better than others in predicting who should be treated conservatively. Four hop tests were compared: single hop, triple hop, crossover hop, and the timed hop. It appears the timed hop test may be one test able to predict which treatment to choose.

In this test, the patient hops as fast as possible to complete a six-meter distance. Adequate quadriceps strength is needed for the test. There is a relationship between successful hopping and overall knee function. Patients who successfully complete the timed hopping tests rate their own function higher.

The fact that your leg gives out from underneath you is a significant factor. This is a sign of joint instability. It does not automatically mean surgery is needed for the best outcome. Knee function after ACL injury can improve even when there is joint laxity.

The force of muscle contraction on either side of the joint can be enough to support and stabilize the joint. Neuromuscular control of the muscles can be improved. With rapid, coordinated muscle contraction, the muscles control how much the joint slips and slides forward.

To avoid surgery, you will need a specific rehab program to address motion, strength, stability, and neuromuscular control. A sports physical therapist can help you with this.

Many people are working toward finding a way to predict which athletes can go to rehab and which ones should have surgery. Either way, the goal is to get the athlete back in action as soon as possible.

Many believe that highly active athletes need surgery more often than less active individuals. Others follow the guideline that anyone with an ACL tear is at risk for reinjury. And reinjury means even more damage to the meniscus and bone.

Often the amount of joint laxity present is used to determine degree of injury and the likelihood of surgery. Laxity in the knee is tested by measuring the amount the tibia (lower leg bone) slides forward under the femur (thigh bone).

But a 10-year study at the University of Delaware has disproved this method of guiding the surgery-verus-rehab decision. They tested many athletes with an ACL tear and found that anterior knee laxity and preinjury activity level are not good predictors of outcome.

They have proposed a new guidance system. It is based on a battery of clinical tests that look at neuromuscular adaptations of the joint. Neuromuscular adaptation refers to the ability of the muscles to contract at the right time and in the right amount to hold the tibia in place even without the ACL.

Several hopping tests are useful in making this determination. Further research is underway to find out if all four of the hop tests are needed (single hop, triple hop, crossover hop, timed hop). It’s possible that there is one hop test best suited to this problem. Or it may be that the tests should be done in a specific order for the best results.

Evidently, not everyone has a good joint stiffening strategy to serve them in the absence of a normal ACL. But rapid, coordinated cocontraction of the muscles that cross the knee (hamstrings and quadriceps) can be achieved with the proper training program.

Talk to your surgeon about all the treatment possibilities available in your area. Ask your physical therapist to review this study and see if you qualify for conservative care.

You may want to discuss this with your primary care physician. Pain relieving medications and antiinflammatory drugs used correctly can be helpful.

An exercise program targeted at muscle strength in the legs may be helpful, too. A physical therapist (PT) can help you with this. The PT will test your muscle strength and find areas of imbalance or weakness. Specific exercises can be used to help correct this problem.

Proprioception should also be addressed. This is the sense you have of where your joints are at any one time. As you move, special receptors in the joints, muscles, tendons, and ligaments relay information to the brain about joint position.

Damage to the joint and soft tissues from osteoarthritis can reduce your proprioception. The joint becomes unstable. Painful symptoms may increase, making it difficult to keep up.

A combination of these various techniques may be needed at first. After six to eight weeks, you should see a difference in your walking speed, distance, and quality of gait (walking pattern). With less pain and improved proprioception, you will likely be able to keep up with the best of them. Good luck!

For a very long time, our understanding of the knee joint cartilage was limited. Scientists knew that the knee cartilage doesn’t heal well or at all. The lack of a direct blood supply to this area left us with the feeling that nothing could be done.

Today, this is far from the truth. Studies in the 1970s and 1980s opened up new avenues of research for improved treatment of knee osteoarthritis (OA). The mechanical properties of articular cartilage were better defined. For the first time, we saw how the dynamics of friction and fluid affected the cartilage.

At the same time, risk factors for OA were more clearly identified. The influence of age, obesity, joint injury, and mechanical stress was recognized. Weight loss and activity became important elements of knee OA prevention and treatment.

And now, thanks to improved technology, we have ways to surgically repair defects in the cartilage. It’s possible to stimulate the cartilage to fill in damaged areas.

When selected carefully and followed up with an appropriate rehab program, many patients like you are remaining active much longer than previous generations of arthritis sufferers. Don’t wait to seek medical help. The sooner an accurate diagnosis is made, the sooner the right treatment and prevention measures can be applied.

The technique you are referring to is called microfracture. It is designed to help full-thickness articular cartilage lesions heal. It seems that if left alone, the body doesn’t heal this area fully or completely.

It is both a safe and effective treatment technique. Many studies have been done and reported on. Results seem to depend on choosing the right patients. The lesion must be well-contained and not too large.

Surgical technique is also important. The surgeon uses an arthroscope to work inside the joint. The area is cleaned and smoothed in preparation for the procedure. Any pieces or fragments of cartilage should be removed.

Then special surgical tools called awls are used to make tiny holes into the bone marrow. Tiny drops of blood and fat from the marrow seep into the holes and fill them. This is the start of the healing phase. Before leaving the joint, the surgeon will also take the time to look for any scar tissue or meniscal tears that require repair or removal.

By drilling through the subchondral bone, channels are formed that allow bits of bone marrow to clot in the holes. A network of blood clots form into a scaffold. Capillary vessels then form to supply the area with blood supply. Stem cells from the bone marrow form into new cartilage cells.

The fibrocartilage that forms isn’t the same as natural cartilage. The surface is not as strong and must be protected carefully during healing. The results are usually excellent. Pain relief, restoration of joint motion, and return to full function can be expected.

Patellofemoral pain syndrome refers to pain around and under the patella (knee cap). Males and females of all ages from teens on up can be plagued by this problem. Athletes are especially affected.

But the cause of the problem still remains a mystery of sorts. We know that an increased Q-angle is part of the problem. You’ve probably had someone measure your Q-angle and possibly tell you it is increased from normal.

The angle is a measure of the alignment between the femur (thigh) and tibia (lower leg). A line is drawn from the anterior superior iliac spine (ASIS) to the middle of your patella. The ASIS is the sharp pelvic bone you can feel in front of your body. When you put your hands on your hips, the ASIS is usually right under your index finger.

A second line is drawn from the patella’s midpoint to the tibial tubercle. The tibial tubercle is the bony bump just below your patella. The angle that’s formed by these two measurements is the Q-angle.

An increased Q-angle means the patella is being pulled laterally (away from the other leg). This alters the way the patella tracks up and down over the femur. The result is increased stress on the patellofemoral joint.

One way to combat this problem is to strengthen the quadriceps muscle. The focus of strengthening is on the medial (inner) portion of this muscle. This may be able to help overcome or balance the lateral pull on the patella. Taping and bracing often help as well.

A well-rounded rehab program also includes strengthening of the hip muscles. You should be tested to find areas of weakness and target those muscles in particular. A physical therapist or athletic trainer can help you with this.

Patellofemoral pain syndrome (PFPS) is a common cause of knee pain, especially in athletes. The exact cause of this problem is unknown so successful treatment is sometimes by trial and error. What works for some people, doesn’t work for others.

Some simple but effective approaches include taping, bracing, and strengthening. A physical therapist or athletic trainer can help your daughter find what works best for her.

Some athletes try everything at once in an effort to control the pain and stay in the game. Others prefer to try one thing at a time and then combine treatment if none of the individual treatment methods work.

Recently some studies were published advising the need to strengthen the hip muscles to help overcome this problem. It seems that weak hip abductor and external rotator muscles may cause increased torque on the knee. Whether this is the cause or the result of PFPS is under study.

There’s general agreement that a rehab program targeting hip and knee musculature can’t hurt and will likely help.

Some rehab experts suggest using the athlete’s age, level of activity before the injury, and amount of joint laxity to make this decision. High-level athletes who want to get back to their former level of play are often advised to have the surgery right away.

But a group of researchers at the University of Delaware put this idea to the test. They developed a screening tool to help them decide who should have physical therapy, who was a good rehab candidate, and who needed surgery right away (or within 30 days).

They used a special screening test and exam to help in the decision-making process. They found that patients with an anterior cruciate ligament (ACL) tear who also had other knee injuries were best off having the reconstructive surgery right away.

Patients who still had painful swelling, redness, loss of motion, or extreme weakness, were sent to physical therapy for a month. Anyone who did not recover enough to move on to rehab was then sent to the surgeon.

And patients who passed several hop tests performed on the injured leg were good rehab candidates. They were able to return to their sport after rehab and participate without further knee instability. Anyone who still had knee joint instability after rehab was also sent to the surgeon.

Computer-assisted surgery is not the gold standard approach for TKRs yet. There is still much that needs to be studied and compared between the open incision method (the current gold standard) and what can be done using today’s technology.

Computer navigation can help insure a better match between the joint and the implant size. It can also analyze joint angles measured on X-ray to find the best placement for the implant.

Poor alignment due to suboptimal implant positioning can lead to uneven wear and tear on the implant. This can cause the implant to loosen and ultimately fail. An unstable joint would likely require additional surgery.

Computer-assisted TKR is fairly new. It’s not available everywhere. A fair amount of training, skill, and expertise are required in order to use this approach. But it can speed up the patient’s rate of recovery.

With less blood loss, there are also fewer postoperative problems. Fewer muscles are cut so there’s less pain and less need for pain medication. You can be up and walking the next day.

By the end of the month, many patients who have had this type of surgery are walking independently. They no longer need a walker or crutches. And they can walk for more than 30 minutes.

Many changes have been made in the way total knee replacements (TKRs) can be done surgically. The standard, open incision is still the most common approach.

But new and improved surgical tools and computer equipment have opened up many more possibilities. The minimally invasive (MI) approach uses a much smaller incision than the standard surgery. The surgeon uses a special tool with a tiny TV camera on the end. The camera allows the surgeon to see inside the joint.

MI surgery is not perfected yet. The surgeon does have a view but it is limited. With experience, the surgeon is able to complete the replacement with less blood loss. The patient often has a faster recovery since less soft tissue is cut in the process.

Computer-assisted navigation adds yet another benefit. This program makes it possible to obtain a neutral alignment of the implant. Poor alignment is what often leads to joint pain, loss of function, and even implant failure.

Efforts are being made now to combine computer-assisted navigation with the MI approach. Using both together, studies show it is possible to get within three degrees of normal or neutral alignment. Patients regain function faster and leave the hospital sooner.

In time, these more advanced types of surgery may be able to save on the cost of a TKR. Total rehab costs may also be decreased if the patient is able to go home sooner. More study is needed to make sure patients aren’t losing function or trading some benefit from the standard approach by having these more advanced methods.

There’s no real concern about the program being in error or failing. These kinds of programs are tested and retested over an over before ever being used on a human. The surgeon’s skill is still what you count on for a good result.

Several studies have been done to help chart the course of patients with total knee replacement (TKRs). Most of the research shows that patients make the greatest strides in recovery during the first nine weeks. That’s just about the time you’ll be heading off to help your daughter.

A home program of exercise usually continues for another three months. Many patients have reached close to their full recovery potential at the end of six months. With persistence and hard work, further improvements can be made. Most often, it’s the older athlete who pushes through to this level.

Improved joint motion and decreased pain make it possible for the average TKR patient to resume normal walking by the end of 12 weeks. Getting up to speed and walking distance can take up to six months.

One predictor therapists and patients can rely on is the patient’s functional status before surgery. The better your motion, strength, and function before surgery, the greater your chances for maximum improvement after the operation.

By the time the baby comes, you should have a good idea of your abilities and limitations. Pace yourself. Don’t take on more than you can handle. Keep up your daily exercise program. These three simple steps can help you recover quickly and make it possible to resume your daily activities.

Most patients find that their greatest improvement comes in the first three months after surgery. Gains in joint motion and strength help increase function. Walking speed and distance improve as well.

Sometimes patients improve more than they realize. Tests that measure their function and physical performance show better results than what they self-report.

Experts aren’t sure why there is such a difference between actual and perceived results. It may be that different aspects of physical function are measured from one test to another. It’s possible the tests used to measure recovery don’t include the types of skill patients are hoping for.

Patients aren’t always told what to expect during rehab and recovery. This could influence how outcomes are viewed. Studies show that maximum function after total knee replacement is reached right around the six to seven month mark. This can vary from patient to patient depending on general health and pre-operative status.

Those patients who have better function before surgery tend to end up with the best outcomes after surgery. Patients with the lowest pre-operative function make greater gains at first compared to less impaired patients. But their final results aren’t as good.

It may be helpful to talk with your surgeon and/or your physical therapist. Find out what are realistic goals for your situation. You may be right on target but don’t know it. Or there may be some additional steps you can take in the rehab process to get the maximum results you desire.

Facing the prospect of knee replacement surgery can be frightening and concerning. Few people look forward to such an experience. However, if your knee has gotten to the point that your doctor is recommending surgery, there are other issues to take into account if you do not have the surgery.

For example, if your mobility is limited, you will be moving around less and less, not getting the exercise your body needs to stay healthy. Pain, which is likely an issue, can keep you from enjoying life, as well as taking care of every day tasks.

That all being said, not all surgeries are successful and, even if a surgery is successful, there are times when other issues make repeat surgeries necessary.

There are a few reasons why a knee replacement may have to be revised or redone. The most obvious reason is if the implant fails somehow. This could be through loosening of parts or a failure of the implant itself. If you receive a partial implant, this could mean having a new surgery to have a total implant inserted.

Sometimes, revision surgery is not from a fault in the implant, but in the progression of disease or disability that caused the need for the replacement to begin with.

According to the US FDA (2003), 90 percent of people who have knee replacements are happy with the results. Studies examining the success of knee replacements found that in about 10 percent of cases, revision surgery was needed after 10 years, and in 20 percent after 20 years.

The knee seems like a simple joint, but it plays a large role in your mobility and stability. Your knee bears your weight and must coordinate the tibia (thigh bone) with the femur (shin bone) and the patella (kneecap) so you can walk straight and fluidly.

The bony parts of the knee work contain the ligaments that stabilize the joint. The muscles above (quadriceps) and below (calf) move the knee, with the ligaments holding everything together. If you add into the mix, the cartilage, also called meniscus, you have another part that can be injured. This lies across the bone and helps the weight be evenly distributed. Because there is so much going on, there is more potential for injury to any of the ligaments, bone, or muscle.

It’s not clear what is the natural history of mild posterior cruciate ligament tears. Natural history refers to what happens over time after an injury occurs if no treatment is provided.

In the case of mild PCL injuries (grade one or two), it appears that the knee can recover. Rehab to help strengthen the muscles around the knee can help.

No one is quite sure what is the final outcome. Follow-up studies of athletes with PCL injuries are limited. There are some reports of permanent instability of the knee joint. Arthritis may develop resulting in a loss of knee function.

Until more is known, most experts recommend a rehab program to recover strength, proprioception (sense of joint motion), and endurance. A physical therapist can help set you up with such a program. Besides restoring more normal function, rehab may help prevent further injury and keep you in the game.