Cartilage Treatment and Transplantation
Lately, we are witnessing increasing cartilage problems which are of non-traumatic, degenerative nature. They usually develop in the knee while the age limit is moving towards adolescence, even child age.
More and more young athletes frequently come to me for examinations complaining of knee pain. Usually problems appear around the patella and they are characterized by pain during and after weight bearing, especially when walking uphill-downhill or after staying in certain positions for a longer time (half squat, prolonged sitting, change of surface, etc). Apart from pain, patients complain about “squeaking” during walking and moving the knee. During clinical examination, usually more or less damaged patella cartilage is found. These problems are not only characteristic for sports related loading but can also be found in persons who are not actively engaged in sports. The only possible treatment for degenerative problems is physical therapy and the correction of physical damage. In athletes, in cooperation with their trainers, it is necessary to modify the focus of loading, avoid full squats or squat jumps. Also, running on hard surfaces, uneven terrain and especially uphill-downhill is harmful. Trainers should by all means try to find alternative activities which would enable their young athletes to stay in sports as long as possible.
Non-athletes should watch out for excessive weight and should, at least weekly, start riding a bike, roller skates or, under expert supervision, strengthen the upper leg muscles which would strengthen the knee extensor mechanism and thus reduce the load on the patella.
Unfortunately, modern orthopaedics is still not able to resolve entirely such degenerative problems. When they deteriorate significantly, arthroscopic surgery is performed followed by physical therapy and applications of fluid containing hyaluronic acid salts (Hyalgan, Synocrom, Synvisc i sl.). It is still not certain how it works but since the mentioned ingredients can no longer be detected in the joint only a few days after being applied, it is believed that somehow they “feed” the cartilage together with the synovial fluid by process of diffusion.
Apart from degenerative problems, there are also cartilage injuries. The same as meniscus tears, cartilage surface of the joint can also “rupture”. In adolescents, the most common injury is osteochondritis dissecans where a sharp-edged fragment of cartilage or cartilage with subchondral bone cracks away from convex joint surfaces. The mentioned pieces can cause the joint to block, swell or hurt. In people above the age of 20, contusion to the cartilage is possible and further damage can cause a limited cartilage defect which manifests in all the mentioned clinical symptoms. In the past, these injuries were unresolvable and often meant that one’s career in sports was over.
Recently, cartilage transplantation technique started being used. For now, it is applicable only for younger population (until the age of 40). The results are extremely promising and more than 80% of patients consider the outcome of their operation excellent or very good. As far as cartilage defects go, there are practically no limitations. This technique can overcome defects larger than as many as 3 cm, although the rate of success falls proportionately to the size of damaged surface.
Until now, cartilage transplantation technique has been mostly used for knee and ankle joints as these are most prone to injuries.
The procedure is twofold. Firstly, knee arthroscopy is performed to examine the defect, clear the knee from loose and damaged cartilage pieces and measure it. During procedure cartilage pieces are taken from load-free surfaces and put into a prepared solution. The tissue is then sent to a laboratory where the process of creating new cartilage tissue starts, the so called tissue engineering.
The engineering process is defined as “persuading” your own body to cure itself by supplying adequate cells, biomolecules and intercellular tissue.
In the cartilage transplantation process this is exactly what happens. Proper cartilage cells are multiplied using special procedures and then grown onto a net which completely consists of hyaluronic acid (HA).
Hyaluronic acid has been found in large amounts in embryonic tissue at the moment when morphogenetic joint formation process starts. Afterwards, its amount significantly decreases. In adults, there is no HA in the joint what brings us to a logical conclusion that the lack of HA inhibits the regeneration process of cartilage.
By placing proper cartilage cells into material whose main ingredient is HA, in fact, we provide them with ideal conditions where they can multiply and create cartilage tissue which, after being placed onto a defect, takes on the characteristics of joint cartilage.
Therefore, in the second part, again arthroscopically, we cover the defect with the prepared tissue and finish the operation.
The mentioned technique is very gratifying. In fact, two smaller surgeries which last for about half an hour and which can be carried out in local anaesthesia, solve a lot. Moreover, returning to normal weight bearing is exceptionally fast. We begin with joint movements already on the first postoperative day, first passively and afterwards actively (bicycle or cyclette). In three to four weeks we allow full weight bearing. Then, the patient needs to start strengthening the muscles. After three months we allow straight running but returning to sports is not allowed yet – six to twelve months are necessary for that. It all depends on the conditions in which the muscles and operated joint are.
Control arthroscopic procedures and taking testing samples have confirmed that already after twelve months “new cartilage” starts behaving as though it is not damaged and produces large amounts of collagen type II and other extracellular matrix ingredients. After 24 months, its complete integration with the subchondral bone has been noticed.
Indications for this technique were initially only trauma related defects, however, gradually we are now expanding them to cover degenerative problems which are caused by instability or deformity of limbs, but with previous or even simultaneous solving of the cause.
The results are very promising. Until now, all the patients who were operated in Croatia using this technique, returned to their everyday activities without any problems.
Prim. Mladen Miškulin, MD, PhD
Specialist in orthopaedics and traumatology