Osteoarthritis: Your Choices and Future.
C. Thomas Vangsness, Jr., M.D.
Professor of Orthopaedic Surgery
Chief of Sports Medicine
Keck School of Medicine
University of Southern California

Los Angeles Osteoarthritis

Millions of Americans suffer from osteoarthritis, a disease that affects the cartilage of joints. This overview serves to educate patients about the many options available for treating osteoarthritis of the knee joint.


Cartilage is made of a protein called collagen, and is designed to absorb the energy and shocks during weight-bearing. Articular cartilage is a glistening white 3-4mm thick tissue attached to the end of the bone. Osteoarthritis is the thinning and chemical destruction of this tissue occurring from normal “wear and tear” or a traumatic injury. Hereditary can also influence this. Osteoarthritis most often affects the large joints such as the knee and hip. Once the cartilage is worn out, the underlying bone surface is exposed. This bone has nerve endings which cause pain when irritated by joint motion.


Osteoarthritis can affect part of, or the entire joint. The knee has 3 compartments: the patello-femoral, or “knee-cap” compartment; the medial (inside) compartment; and the lateral (outside) compartment. Isolated single compartment osteoarthritis can result from an abnormal lower extremity alignment or from a previous fracture within the joint. Left untreated, isolated uni-compartmental arthritis can progress to diffuse arthritis involving all 3 compartments. Osteoarthritis in the hip joint tends to involve the entire joint, as does arthritis of the shoulder. Osteoarthritis of the knee may involve one compartment, two compartments, or the entire joint.


Since the knee joint is so large and has 3 separate compartments, there is a spectrum of treatments available to you. Treatment begins with initial noninvasive measures, and progresses to “biological” surgical techniques. Finally, if biological measures fail, your treatment algorithm crosses the “biological tidemark” and surgical options are limited to prosthetic (plastic and metal) implants.


Treatment begins with some essentials that all patients with osteoarthritis should know. Weight loss is critical to any treatment plan. Less weight means less future “wear and tear” on the remaining healthy cartilage surfaces. A good rule of thumb is that each extra 5 lbs above the waist adds 50 lbs of additional pressure on the knee for each step taken. We average about 6-10 thousand steps a day.


In addition to weight loss, patients often find relief with a good light exercise program. An exercise program should be designed to increase the flexibility and the range of motion of the lower extremities and trunk muscles as well as strengthen the major muscle groups. Trunk stability and quadriceps muscle strengthening are very important. It is an established fact that there is no correlation with x-ray changes and joint function. Even with increased O.A. on x-ray there may be little or no joint pain. Exercise is important for the biologic future of the joint.


Well cushioned shoes can help decrease the jarring fibers across the joint. A cane in the opposite hand of the arthritic joint can also decrease joint forces and pain.
If only one compartment of the knee is affected, an “unloading brace” can provide pain relief. These braces serve to shift forces to the normal compartments, putting less pressure on the diseased compartment. Isolated patello-femoral arthritis (under the knee-cap) may be alleviated with a brace that forces the knee-cap into a less painful position during flexion/extension. Knee-caps that tend to move outwards during knee flexion/extension cause arthritis and pain.



Next comes pharmacological agents… topical creams and pills. Osteoarthritis sets off a chemical reaction inside the joint. This reaction is your body’s immune system trying the “heal” the injury, which creates a great deal of inflammation (swelling and pain). This inflammatory cascade releases molecules into the joint called “cytokines” and these molecules create pain and more damage. Drugs that limit the amount of inflammation and prevent the formation of these cytokines are critical to the pharmacological treatment of arthritis. This class of drugs is referred to as “anti-inflammatories”, and includes over-the-counter drugs such as ibuprofen, motrin, aleve, aspirin, and naprosyn. Note that Tylenol is NOT an anti-inflammatory medicine. Non-steroidal anti-inflammatory drugs (NSAIDs) are the most common medications used to combat arthritis, but patients should be aware of their side effects. NSAIDs can cause bleeding, stomach ulcers, and (rarely) kidney damage; generally they do not affect the liver. Tylenol is the pill that can be hard on the liver. Some patients find relief with the various topical agents (lotions) that can be applied directly over the area of maximal tenderness. These topicals include different NSAIDs or capsaicin (another compound that limits inflammation).


A natural pharmacologic compound found to help relieve the pain of arthritic joints is glucosamine and chondroitin sulfate. There are a number of over-the-counter forms of these compounds. There are several studies that show these to be significantly effective for pain relief. Glucosamine and chondroitin sulfate have very little side-effects and are less expensive than most NSAIDs.


Knee inflammation can be controlled by injecting a dose of anti-inflammatory medication directly into the joint. These injections typically contain a “steroid”, which works similarly to the non-steroidal medications described above. The steroid medication is often cortisone, which I mix with a numbing medication such as lidocaine. These injections can reduce inflammation and pain for shorter (weeks) periods of time. Multiple injections can be given over time but this is not a great long-term solution. The medicine in these injections has very little effect on the rest of the body. Risks include infection inside the joint (very rare) and an occasional skin discoloration around the site of injection (especially in persons with darker skin).


Recently, injectable forms of the naturally occurring compounds that lubricate the knee joint and affect cartilage cell metabolism have become available. These include the 5-6 different hyaluronic acid (H.A.) products currently on the market. There are many published reports of the benefits of these injections on moderate arthritis. This treatment necessitates a series of 3-5 weekly injections, and may not be covered by your insurance policy. In the future, new inflammation controlling or reducing medicines will be directly injected into joints.
The above modalities are available to anyone, regardless of age. They serve to temporarily alleviate pain, and perhaps slow the progression of osteoarthritis. When pain continues after these treatments have been tried, surgical options for pain relief must be considered. These range from surgical procedures that preserve the natural biology of the functioning knee joint, to those that replace parts or all of the knee joint with metal and plastic prosthetic components.


Surgical Options
Simple arthroscopic surgery can be used for the treatment of O.A. Arthroscopy for the treatment of arthritis is really only temporarily beneficial except for some of the mechanical symptoms associated with arthritis. Studies generally show that there is no long-term benefit with debridement of the knee and arthroscopic lavage (rinsing of the joint with arthroscopy fluid).


Arthroscopic surgery commonly involves the meniscus, a flat half circle of tissue made up of tough yet soft fibrocartilage. One meniscus is found in the inside medial knee compartment, and the other is found in the outside lateral compartment. These serve as additional shock absorbers during activity, protecting the articular cartilage surfaces on the ends of the bones. With normal wear and tear, the meniscus can get torn or degraded just like the cartilage on the bones. Once the meniscus tears, it often causes a feeling of locking, catching, and popping inside the knee joint, as well as pain. These tears can be treated with arthroscopic surgery, often simply to remove the portion that is torn leaving as much healthy meniscus as possible. In some young patients (<40), certain tears can be repaired with sutures. If the entire meniscus has been injured or removed, you may be a candidate for meniscal transplantation. Meniscus transplantation is reserved for those less than 55 years old with mild arthritis. Short-term data indicate that transplantation can be successful as a pain relieving operation.


During normal arthroscopic surgery, the cartilage surfaces on the joint are carefully inspected. Specific full thickness cartilage lesions can be treated at this time. I will determine if the lesion is appropriate for arthroscopic treatment, or requires additional invasive (open) procedures. Some lesions can be treated with a “drilling,” or “picking” (microfracture technique), or chondroplasty (smoothing the exposed bone and torn articular cartilage with a small rotating tool). These terms refer to any procedure that stimulates the bone marrow cells to re-grow new fibrocartilage cells and fill in the defect. This is only useful for smaller lesions that are discovered on direct inspection rather than on x-rays. Studies suggest a short-term benefit, approximately 50% of the time with microfracture techniques.
If the lesion is larger, it can be treated in a number of biological ways. One way is to culture your own cartilage cells and grow new ones in the laboratory. Once these have grown, I can implant these new cells into the cartilage defect. This defect is then covered with a patch of normal tissue and a new cartilage surface forms in a few months. This is not perfect hyaline articular cartilage, yet this tissue is better than seen with the microfracture technique. This procedure requires 2 surgeries and is more costly. It has long-term data showing pain relief.
Another option for large cartilage defects in one compartment of the knee is to take thin circular plugs of normal bone and cartilage from a different area/compartment of the knee that does not bear weight, and implant them into the defect. These plugs then incorporate into the normal surrounding areas. Results from this procedure (OATS/mosaicplasty) are not as pleasing as initially thought.


To avoid sacrificing normal bone/articular cartilage, another option is to use segments of bone and cartilage from donors. These cadaver parts are referred to as “allografts”. If there is a very large area of joint that is affected, and is too large to use a group of plugs, then I may transplant a large portion of the joint from a donor. The osteochondral graft is cut and shaped to replace the specific area of your knee that is affected. This graft is secured in place with metal or bioabsorbable screws. Once implanted, the cadaver tissue incorporates itself into your normal surrounding tissue. There is no rejection with this transplanted tissue. The cartilage cells survive in good numbers. There is little risk of infection or disease transmission with modern tissue banking. Allografts tend to take longer to incorporate (perhaps 6-12 months). The transplanted tissue may collapse, or dissolve partly, leaving uneven surfaces behind (failure rate can be as high as 30%).


If you do not want to take the risks of allograft tissue, then a realignment procedure (osteotomy) may provide pain relief. If your lower extremity is in excessive angulation at the knee joint, then excessive pressure is placed on one compartment, causing the osteoarthritis. This is referred to as varus (bow-legged) or valgus (knock-kneed). This realignment procedure involves cutting the bone below the knee joint (the tibia), and removing a wedge of bone to correct the tibia angulation. With a corrected alignment, pressure is transmitted across the normal joint compartment. The cut bone is then stabilized with a metal plate and screws. This procedure is reserved for active patients, less than 50-60 years old.


Finally, if none of these biologic procedures is best for you, you must cross the biological tidemark and proceed with a prosthetic (metal and plastic parts) implant. There are a number of prosthetic implant designs, with 2 main categories: unicompartmental replacements; and total knee replacements.


A unicompartmental replacement replaces the bone and cartilage on both sides of the joint in only ONE compartment, medial or lateral. These replacements work great for pain relief, but don’t last forever. Plan on 10-15 years for a unicompartment replacement. In order to qualify for this procedure, the rest of your knee joint must be free of any arthritis. Just released for patients are new partial covering metal caps for smaller arthritic areas of the femur. This may be tried before replacing the entire compartment. Patients older than 60 tend to have arthritis in the remaining compartments, and are most often treated with a total knee replacement.


Total knee replacement is an extremely successful operation, in America today with 90% of patients pleased with their results. This surgery will relieve the pain from knee arthritis. It involves replacing the bone and cartilage on both sides of the joint, as well as underneath the “knee-cap.” Prostheses are made out of a cobalt-chrome metal, with polyethylene plastic inserts in between the metal. Total knees last for approximately 10-15 years, after which time many patients require a second operation. Total knee replacements wear out with normal activities, just as a normal knee does. Patients are warned that the lifespan of their prosthesis is dependent on how much activity the prosthesis experiences. Once a total knee needs to be revised surgically, more bone is removed making the next surgical procedure more difficult.


This is a brief overview of all the treatment options available to treat your arthritic knee. Some treatments are appropriate for you, and I can discuss these with you. In the future, expect new treatment modalities that involve molecular biology. Current research with stem cells and cartilage cells are underway, and there is hope for a cure for arthritis in the upcoming decades! This research will make replacing joints with metal and plastic a thing of the past. Good luck in your journey to find relief from the pain and stiffness that you are suffering!