Viscosupplementation consists of injectinghyaluronic acid directly into the joint, especially at the knee. It is offered when other treatments (drugs, etc.) are no longer effective enough and before considering the fitting of a prosthesis. Hyaluronic acid is a viscous and elastic substance naturally present in the synovial fluid, which covers the cartilage. But, in the joints affected byosteoarthritis, it is of lower quality and in less quantity, which makes the cartilage more vulnerable to friction. The injections then make it possible to alleviate this problem, to lubricate the joint, to improve its mobility and to reduce the pain. “We consider that these injections give good results in 70% of cases”, says Dr Jean-Luc Renevier, rheumatologist. However, they must be renewed every year, cost 100 to 250 € and are only covered by health insurance for osteoarthritis of the knee.
Much research is currently being carried out around the world on stem cells. Taken from the bone marrow, where they are more specialized for the creation of cartilage and bone, or from the adipose tissue of the patient, they are, in principle, capable of transforming into any type of cell and therefore, why not, in cartilage cells. In Marseille, Dr Michel Assor, orthopedic surgeon, uses stem cells from the bone marrow to rebuild cartilage. The first results of a clinical trial were recently published: they are favorable over a period of four years. If they are confirmed, the treatment could be validated definitively. According to the surgeon, this technique could significantly limit the number of knee prostheses.
“When osteoarthritis affects the hip, fitting a prosthesis is the treatment par excellence. The pain disappears the next day and there is no longer even a need for rehabilitation ”, says Dr Renevier. The prosthesis is also the only surgical treatment curing osteoarthritis of the hip. And it is the only one to be supported by Social Security. Concerning the other joints, things are unfortunately a little more complicated. “In the case of osteoarthritis of the elbow, wrist, ankle or shoulder, it is sometimes possible to fit a prosthesis. But, for the moment, these are often fairly experimental models and we have little perspective on their effectiveness ”, says Dr Renevier. For the knee, there are two main types of prosthesis. Either partial: one replaces only one of the three compartments of the knee (internal, external or patellar). Either total: we replace the cartilage of two or three compartments. The surgeon chooses one or the other depending on the severity of the osteoarthritis. Nevertheless, admits the rheumatologist, “Knee prostheses remain less efficient than hip ones. After the operation, it takes at least two months of rehabilitation and it often takes a year before the patient regains all his mobility and no longer feels any pain ”.
In some cases, osteoarthritis of the knee can be due to a malformation of the bones of the leg (most often the tibia, sometimes the femur): these are not perfectly straight, which leads to localized wear of the cartilage. The osteotomy therefore consists of cutting the tibia and inserting, at the level of the section, a callus to straighten the leg bone. If it does not repair the osteoarthritis in itself, this surgical treatment relieves the support of the knee and, if it is carried out in the first stages of osteoarthritis, prevents it from getting worse, which is all the more important as the patient is young. “This intervention is effective in the long term for moderate osteoarthritis but, for stage 4 osteoarthritis, with extensive loss of cartilage, the pain reappears after a few years and the degradation of the cartilage continues”, says Dr Assor.
Practiced only by a few surgeons and rheumatologists, a new treatment involves drawing blood from the patient, then centrifuging it to extract the plasma with platelets and growth factors. After possibly adding a little hyaluronic acid to the mixture, it is injected directly into the joint, under local anesthesia. The patient returns home after 10 minutes of rest. “These injections of PRP (platelet rich plasma) appear to be more effective against pain than those of hyaluronic acid. In addition, it is believed that the growth factors it contains stimulate the remaining cartilage cells, which could help repair the cartilage. It is still necessary to prove it and for that, clinical trials are currently underway ”, says Dr Renevier.
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Say doctor … Can we have a prosthesis fitted at any age? A hip prosthesis has a lifespan of twenty years, sometimes more. It is therefore possible to apply it to fairly young people, around 50-60 years old. From now on, it can also be considered at 80-90-years of age, in patients in good shape, who can resume walking two days after the operation and thus regain a good quality of life. l For the knee, it’s a little trickier. In principle, we wait 60 years, when the daily embarrassment has become too important. We avoid doing it too early, because a young person puts more work on his joint, which weakens the prosthesis. Resuming activities must be careful, avoiding certain sports. |
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