Knee Arthritis Options For Treatment
Knee arthritis
Treatment non-operative
Treatment Operative
Knee Replacement
- Decision making
- Partial Knee Replacement
- Total Knee Replacement
- Minimal Incision Surgery
- Pain control in Knee Replacement surgery
Types
The word arthritis literally means ”joint inflammation” but in the medical field we use the term arthritis to describe many conditions that cause destruction of Joint surface even if inflammation is not a major player. Many of the arthritic conditions that we treat such as Rheumatoid arthritis, Gout and Systemic Lupus have inflammation as the primary cause of the joint destruction, but in the most common form of arthritis, osteoarthritis, there may not be any inflammation present at all.
Osteoarthritis
Osteoarthritis is also known as degenerative joint disease. This is simply caused by a wearing out of the joint surface in the knee faster than the body can repair it. It is much more likely to be present as we get older, but there is a great deal of variability in osteoarthritis from person to person and even from side to side in the same person. This is because there are many predisposing factors leading to the wear and tear. If we can recognize some of these factors we may be able to stop or slow the progression of the arthritis.
Factors / Progression
If a person is lucky enough to have a leg that is in perfect alignment, with normal stability, never injured, with ideal body weight, and is willing and able to avoid repetitive stressful activities in sport, play and work, they will not develop osteoarthritis in the knee. For the other 99% of us there is a chance that the knee will wear to some degree in our lifetime. Knowledge of the risk factors will help us discover how to keep our own natural knees working well for a long time.
Alignment
You have probably noticed that sometimes it seems that knee arthritis runs in families. If it does in your family, it is not due to any specific gene, but is probably related to the inherited overall alignment of your leg. Knees that are bowlegged or knock-kneed do not distribute the weight equally across the surface of the knee. If the degree of bowleggedness is great, all of the weight may be placed on only half of the knee joint causing accelerated wear. A kneecap that is out of alignment also may wear unevenly causing arthritis in the front of the knee.
Instability
Knee laxity or instability, from an injury or naturally present, may increase the stress on the knee joint because of abnormal movements that increase shear or scraping forces on the joint surface.
Injury
Injury to the knee at any point in your lifetime can make the knee more susceptible to arthritis. Sometimes, a meniscus tear or bone bruise may accompany an injury to the joint surface. These injuries may not completely heal and then increase the chance of arthritis later in life. Fractures through the tibial plateau or through the joint surface can directly cause post-traumatic arthritis. There is almost always a history of past injury when the arthritis is predominantly in one knee.
Weight
The sad fact is that much of our population is overweight. The forces through our knee joint surface increase proportionally as our body weight increases. This stress is even more evident when the knee is in a bent position. When we climb stairs, squat, get up from a chair or out of a car we are putting 5-10 times our body weight through the knee joint. These levels of load over time are more than some knees can take, especially if there are other risk factors present. This is especially a problem when we see how the pain of arthritis limits our ability to lose weight through exercise.
Activity level
The design of our knees allows us to participate in a tremendous number of strenuous activities. In the absence of other risk factors the knees are safely able to run ultra marathons and ironman triathlons. The most important points for active athletes are good training and conditioning, listening to your knees for pain or warning signs, and remembering the other risk factors. Some workplaces present more of a problem such as those that require constant or repetitive squatting. These may increase the wear on the kneecap and there may not be an option to stop for pain.
It is fortunate that there is a vast array of athletic activities that are safe and recommended for people with knee arthritis. Analysis and treatment of the risk factors is important to maintain the highest level of activity and health.
Preventative measures
Recognition of your own risk factors and maintaining an active lifestyle are important ways to maintain the health of your knee. For the most part, conditioning, activity modification, and prompt careful treatment of injury are the most important steps to a long lasting knee.
Treatment of Knee Arthritis
There is a vast array of treatment options for a knee with osteoarthritis, from simple conservative measures to Partial or Total Knee Replacement. The treatment needs to be individualized depending on severity of arthritis, age, risk factors, level of activity, and many other factors.
First line treatment; Conservative Care
Today, we have more conservative tools and techniques at our disposal than ever before. What follows is an up to date assessment of the current options.
Medications for arthritis
The mainstay for medical treatment of osteoarthritis is the nonsteroidal anti-inflammatory drug (NSAID). These medications are all pain relievers as well as inflammation reducers. Both of these actions can help the person with arthritis feel better and enjoy more activity, but none of the medications are without side effects. The most common side effects are in the GI tract including stomach distress, heartburn, or the more serious ulcers or reflux (GERD). You should not take these medications if you experience any of the above. These medications also can affect the blood in a way that slows your clotting. It is important to avoid NSAID’s if you are taking any medication that thins your blood, including Aspirin, Plavix, and Coumadin (Warfarin). We recently have also discovered some interactions with cardiac drugs and Beta blockers (such as Atenolol). If you are taking any other medications it is important to ask your doctor or pharmacist about drug interactions.
After reading the above paragraph it may appear that nobody can take the NSAID’s, but they can be safely used in the majority of people with osteoarthritis in otherwise good health. For osteoarthritis they are best used taken at a full anti-inflammatory dose for a limited period of time, and then tapered to the lowest dose that will still give acceptable relief of pain. They are most useful for relief of a dull aching and persistent pain and least useful for intermittent sharp catching or stabbing pain.
Although these are mostly used orally (pills), they are also available as creams or patches and can be applied to the skin over the knee. The chief side effect here is skin irritation.
Acetaminophen (Tylenol) is a widely used pain reliever that can very effectively treat the painful symptoms associated with osteoarthritis. It is not associated with the GI or blood thinning or cardiac effects of the NSAID and is generally well tolerated. Caution must be used when taking acetaminophen as it does not give pain relief for a long time per dose and it is taken many times a day for pain relief. This may cause a person to take more than the safe amount. Acetaminophen can cause irreversible liver toxicity when taken at higher doses or frequency. If you are going to use it for arthritis regularly, check with your doctor to determine a safe dose for you.
There are a number of natural products for treatment of osteoarthritis, the most common being glucosamine sulfate and chondroitin sulfate. These compounds are present in normal healthy human cartilage and are needed for cartilage healing and repair, but studies in the medical realm have not been able to show their effectiveness in stimulating repair or producing cartilage in the arthritic human knee. Some studies have cast doubt on their effectiveness to relieve pain in osteoarthritis beyond placebo. Never the less, they are very commonly used and many patients have confidence in this product’s ability to treat the pain associated with their arthritis. They are as popular as they are because they are without the side effects listed above. I would advise caution in their use as they can be expensive, and have doubtful efficacy.
Bracing/Orthotics
Osteoarthritis in the knee is usually associated with alignment problems. The most common misalignment is varus (bowleggedness). When standing on that leg, the weight of the body is not centered in the knee, but instead is concentrated in the medial compartment. This causes the knee to wear out medially (the inner aspect of the leg). In many individuals with varus the knee shifts even more when weight bearing causing a feeling of instability, lack of confidence in the knee, and more pain. In these individuals the knee may feel better with the support of an unloader brace. Since the brace is usually not comfortable enough to wear full time, the brace treatment is especially useful for patients who need to stand at the workplace or who participate in exercise, sports and hunting. If the knee has excessive valgus (knock-kneed) the same progression occurs on the lateral (outer aspect) of the knee. The bracing is usually used in conjunction with other conservative measures such as medication, exercise or injection.
Physical Therapy
Orthopedic physical therapists are knowledgeable and talented professionals who contribute to the treatment of many painful conditions of the knee including osteoarthritis. Their contributions are too numerous to mention in this short passage. The main contributions are in maximizing function and reducing pain through exercise, massage, and many modalities as well as education and establishment of independent exercise programs. We use physical therapy in all aspects of care, especially in recovery from injury, arthritis exacerbations and surgery.
Injection Therapy
There are two major types of injection therapy; steroid (cortisone) and visco-supplementation (hyaluronic acid, Supartz, Synvisc). Each type of injection has its advantages and disadvantages.
Steroid injection
Cortisone and other steroid injections have been used for many years for arthritic pain. It is a strong anti-inflammatory medication that is absorbed into the knee joint lining and decreases the swelling and aching pain frequently associated with flares of arthritis. It is especially helpful in inflammatory arthritis such as rheumatoid arthritis, gout or pseudogout. It is useful in advanced osteoarthritis when there is a flare of acute pain. It may help delay the need for a knee replacement, or be a means of treatment for patients who are not healthy enough for surgery. There is a known side effect of joint surface cartilage softening and therefore is not a good choice in early arthritis in younger people. There is a risk of infection in any joint injection so it must be placed using sterile means.
Visco-supplementation
These thick gel-like preparations are the product of the combs of chickens or they can be synthetically produced. They have been used for over ten years with good success in the properly selected patient with osteoarthritis. Unlike the steroid injection it does not work in days, but it usually takes 4-6 weeks to get the desired pain relief. The injections are given in a series of three to five, each spaced a week apart. If a good response is achieved, it will typically last for 6-8 months. The indication for their use is osteoarthritis with persistent pain despite conservative measures such as NSAIDS, or the inability to take NSAIDs. The patient’s knee x-rays should show at least some joint space remaining, as this is not effective if the knee is “bone on bone”. The preparation is a natural product and is chemically similar to the normal lubricant we have in our knee. It is felt to decrease friction in the knee, but the main benefits for pain relief seem to be related to the decrease in inflammation seen in 4- 6 weeks. Unlike the steroid injection it has not been shown to cause any joint surface injury and theoretically may help the joint. Therefore it is safe in younger individuals with less severe forms of osteoarthritis. The injections can be repeated every six months as long as they are effective and can delay the need for a joint replacement. Ultimately the relief obtained becomes unsatisfactory as the joint surface is lost and the knee becomes” bone on bone”.
Weight Loss
The stresses across the knee joint are directly related to body weight and the length of time that the weight exceeds ideal body weight. This factor is even greater in the patella-femoral (kneecap) part of the joint. This can become a real problem as a painful arthritic knee doesn’t allow a person to exercise. The lack of ability to exercise makes it very difficult to lose weight. It is very important to keep your weight under good control, especially if you have other risk factors such as previous knee injury, positive family history of knee arthritis or poor knee alignment. The increased body weight also increases the surgical risks of infection, DVT and prosthetic loosening. Nevertheless, many people find themselves in this predicament of being overweight and having severe knee arthritis. We can treat the arthritis using all of the previous listed methods and many times need to proceed with surgical treatment. We can have successful results if the patient commits to an exercise and weight loss program before and after the surgery. Warm water exercise and non-weight bearing active exercise can be very important tools in the weight loss and rehabilitation.
Operative Treatment
When conservative measures have failed or conditions exist that make conservative measures likely to fail, operative treatment can offer a solution.
Knee Arthroscopy in Osteoarthritis
Arthroscopic surgery, or Arthroscopy, is an outpatient surgical procedure usually done under a general anesthetic. Three small incisions are made around the knee. Through these incisions a small telescope (arthroscope) is placed to view all aspects within the joint. A high definition miniature television camera is used to project the image on a plasma screen. This allows the surgeon to see into the joint with an incredible amount of clarity. Small instruments can be used to perform a variety of procedures in the knee joint. The most common indication for arthroscopy in a knee with osteoarthritis is to remove a torn meniscus or a loose piece of joint surface (loose body). At the same time the joint surface is examined and can be debrided (cleaned up) as necessary. In certain situations the cartilage defects can be grafted or treated with techniques such as microfracture of the bone beneath the cartilage defect, done through the scope.
The type of symptoms associated with osteoarthritis are aching pain and stiffness, often accompanied by swelling. The pain is usually predictable and increases as the day progresses. Knee arthroscopy has not been found to be useful for treatment of osteoarthritis with this pattern of pain. It is common however to have the meniscus in the knee fray and then tear causing an increase in pain and swelling. This usually presents as an exacerbation of sharp pain that comes on suddenly, and then recurs in an intermittent and unpredictable fashion. The pain occurs when the torn part of the meniscus shifts and gets stuck between the joint surfaces. The pain may be short-lived or the meniscus can become stuck and the knee may lock. In this case you cannot straighten your knee. If this is a persistent problem the meniscus tear is large enough that it will not go away by itself. In this case, arthroscopy is recommended to remove the fragment and inspect the knee. The arthroscopy should return the knee to the way it was prior to the exacerbation. The length of time that it takes to improve depends on the severity of the arthritis.
Tibial Osteotomy
If you notice that your knees do not touch when you stand upright with your ankles together you have varus alignment in your knees. This is commonly called bowleggedness. The larger the distance you have between your knees, the larger the degree of varus. This can be measured accurately with a long standing x-ray that includes your hip, knee, and ankle on the same film. The x-ray should show that a line drawn from the hip to the ankle passes through the middle of the knee, but with varus the line goes through the medial (inner) side of the knee. In severe varus, the line misses the knee to the inside. This is important because that line shows where the weight goes across the knee joint. If the line is close to the center of the knee, your weight is carried equally by both sides of the knee, but if the line is through the medial (inner) edge of the knee all of the weight is carried on the medial half of the knee and hardly any on the lateral (outer) side.
People with severe varus are predisposed to medial compartment arthritis. As the arthritis progresses, the medial joint space gets worn down causing the knee to drift even into more varus. This increases the weight on the medial side, which causes more progression of the osteoarthritis. Whenever I do a knee replacement, the long x-ray is taken before surgery to make sure that the malalignment is corrected at the time of the surgery. In some younger individuals, the amount of varus is great in the early phases of medial compartment osteoarthritis. In these people it is best to correct the varus early to prevent the progression by doing a tibial valgus (opposite of varus) osteotomy (bone cutting).
In a Tibial Valgus Osteotomy a wedge of bone is placed in the tibia below the knee on the medial side. This changes the position of the ankle to line up the hip, knee and ankle. A titanium plate is used to hold the bone in position until it has healed. When this is done in a young person with very early arthritis it can prevent the progression and also decrease the arthritis pain and makes the knee feel more stable. Many years ago, before advances in knee replacement this type of procedure was done for treatment of moderate to advanced arthritis and had marginal success. It still has a place early in the treatment of osteoarthritis, in individuals with severe deformity and is commonly used in conjunction with other surgical repairs such as ACL reconstruction, cartilage grafting, and meniscal surgery.
A less common deformity is excessive valgus (knock-kneed) where the knees touch when the ankle are apart. People with valgus may also have patella-femoral (kneecap) alignment problems. Varus Osteotomies, if indicated are more often done above the knee rather than below.
Knee Replacement
The progression of established osteoarthritis can be slowed considerably with a number of conservative measures, but it cannot be reversed. Ultimately, the knee joint surface in the active individual can be worn down to the point where the bone surfaces are grinding against each other. On x-ray this is seen as the well known”bone-on-bone” appearance. Since the sensitive nerve endings are located on the exposed surface of the bone, the knee is painful, especially with weight bearing. At this point, viscosupplementation and NSAID’s no longer are effective.
When it gets to the point where your daily activities are limited primarily by your knee pain, or if you are having pain at night that is not relieved with the above described conservative measures, a knee replacement offers an excellent solution. We no longer think of a knee replacement as a last resort and understand that there are many benefits in replacing the knee before activity levels are severely compromised.
Partial Knee Replacement
There are a number of choices in Knee Replacement techniques available today. These include partial replacement, total replacement, and minimal incision surgery. There have been significant advances in the design, fit, and sizing of the implants; especially for women. There are new more durable knee components available now that have been laboratory tested to times exceeding 30 years. Surgical techniques have advanced and improved the precision of the implant placement and soft tissue balancing. The result is that knee replacements done today should last longer and outperform their predecessors. More surgical techniques are under development utilizing computer directed fitting, computer navigation, and robotics in knee replacement. With so many new ideas and options available, the choices may seem daunting.
It is important to remember that every knee with osteoarthritis is unique. It is important that the surgeon consider all of the factors including the above mentioned risk factors in osteoarthritis to select the appropriate techniques and prosthesis.
Partial Knee Replacement
The knee has three distinct areas where the joint surfaces come together. These are the medial, lateral, and the patella-femoral compartments. In many individuals, the arthritis or joint injury may be restricted to only one compartment. In this circumstance, replacing the damaged compartment and leaving the other surfaces alone can be very successful. The surgery is less invasive, less painful, and the recovery is usually quicker than a total knee replacement. The ACL and PCL can be retained leading to a more natural feeling knee. This is an excellent solution for many people, but is not applicable to everyone with osteoarthritis. The optimal candidate has isolated medial compartment involvement, full range of motion, an intact anterior cruciate ligament and only a mild varus deformity. It is estimated that about 7 out of 100 people with osteoarthritis are satisfactory candidates for partial (uni-compartmental) knee replacement. Although it’s been around for many years, recently there is a lot of enthusiasm for this type of replacement, and therefore a temptation to expand the indications to younger people with generalized osteoarthritis predominantly in one compartment. Pain relief in these individuals is much less predictable and may be short-lived. In this situation progression of arthritis in the remaining compartments may lead to need for a total knee replacement in the future. In partial knee replacements, careful preoperative evaluation and realistic discussion is essential to assure an excellent result over long term.
Total Knee Replacement
The total knee replacement is the most common surgical technique utilized for advanced knee osteoarthritis with over 270,000 performed in the United States every year. Over the last forty years, since John Insall developed the design and instrumentation for the total condylar knee replacement, tremendous improvements have been made. The new components fit much better, move more naturally through a fuller range of motion, have much better longevity, and allow much greater function. Recent advances in the composition of the metals and the plastics show promise for even greater durability and less wear. Because of this, there has been a trend to proceed with knee replacement in younger patients with severe arthritis before they develop contracture, deformities and significant atrophy.
In a total knee replacement all of the knee joint compartments are resurfaced. The tibia is resurfaced with a titanium base plate and stem. An ultra high molecular weight polyethylene (plastic) surface is placed on top of the titanium to be the actual new joint surface. Titanium is the best choice due to many factors, but one of the major advantages is its compatibility with bone. The titanium and bone have similar flexibility and elasticity. Because of this there is less chance of loosening over time.
The plastic used for the joint surface has undergone some significant changes in the last few years. By treating the components with radiation under certain conditions the plastic becomes cross-linked and more wear resistant.
The most significant development recently is the change in the femoral component. The first choice for the femoral component material, used since the inception of the modern nonconstrained knee replacement is a cobalt chrome alloy. This very strong, wear resistant, and polished metal has done very well over the years providing low friction and slow wearing for its own surface and for the plastic surface. But even with these benefits, the plastic component in active individuals would fail after many years with deformation or cracking due to friction of the metal on the plastic. Several years ago a new material called oxinium was developed primarily to be used in patients allergic to metals, as it is nickel free. Oxinium had excellent material properties for strength and low friction and was a good substitute for the cobalt chrome alloy. In fact over the years in laboratory testing it has been shown to be more durable when combined with the cross-linked polyethylene than its predecessor. The total knee replacement with this combination of materials is called the Verilast Knee. I believe that this is the best current choice for the younger more active individual choosing a total knee replacement.
Minimum Incision Surgery (MIS)
Over the last several years a number of approaches have been introduced in order to reduce the size of the operation and thus the morbidity associated with knee replacement surgery. Modifications in the surgical instruments have allowed the replacement to be done with less incision and less surgical dissection. This should translate into less pain, faster progress, and better outcomes. It certainly results in a smaller incision, but the overall results with the smaller incisions have been mixed. This may be due to the limitation of visibility of some parts of the knee due to the limited incision. I believe that there is value in limiting the dissection and the size of the incision in knee replacement surgery to MIS levels, but only to the extent that all of the knee can be well visualized. This means that an individual with a larger knee will need a slightly greater length of incision than the MIS level. It is more important to maximize the outcome than minimize the incision.
Pain control in Knee Replacement surgery
Knee replacement of any kind is a major operation. With this procedure there is potential for moderate to severe pain. The long term success of a knee replacement requires early range of motion, which is difficult if the knee hurts a lot. It is important for the surgeon to develop a pain management plan that prevents severe episodes of pain, while avoiding the strong side effects of nausea, dizziness, hypotension, and lethargy. The standard approach is the use of a general or spinal anesthesia followed by intravenous narcotics (PCA) for pain control.
A new more effective approach is the use multimodal pain therapy. In conjunction with the anesthesia department at Meriter hospital, we have developed a protocol for post-operative pain control utilizing intra-operative knee injections combined with an indwelling catheter femoral nerve block. Our patients have experienced better pain control in the first two days after surgery, avoiding severe pain episodes and using only a fraction of the narcotic pain medication. This is very beneficial in that the perioperative experience is better, the side effects associated with IV narcotics are less, and the early range of motion exercises are much less intimidating. Total knee patients that have had a previous knee replacement on the other side report a dramatic difference in the experience.
Using this technique, just before your surgery, the anesthesiologist will place a small catheter in the front of the hip area under local using ultrasound guidance. Numbing medication will be place into the catheter and you will notice the front of your knee area go numb. During surgery I will place a combination of pain medications into the tissues in the back of your knee while doing the knee replacement. The catheter is left in place for the first two days providing continuous analgesia to the front of the knee. On the second day post-op, when the pain levels are significantly less, the catheter is removed. Pain pills should be all that is needed at this point. The one warning with this technique is that the leg is weak on the first day post-op and you must have help when you get out of bed or you risk falling. During this day the physical therapy sessions concentrate on regaining range of motion in the knee. On the second day, the strength returns and walking with full weight bearing on the knee is added.
