Advances in the treatment of joint damage

Where has progress been achieved in the treatment of cartilage defects?

Especially for defects at the femoral condyle various complex but effective methods have been established, e.g. osteochondral bone-cartilage-transplantation and autologous chondrocyte transplantation (7,15).

Transplantation of bone-cartilage-tissue with the so-called mosaic graft procedure has been used since beginning of the 1990s to fill isolated cartilage defects with natural cartilage-bone tissue.

For the chondrocyte transplantation, natural cartilage cells are removed. They are reprocessed using a complex procedure and then replanted into the defect during a second intervention.

This technically and surgically complex procedure has shown promising results in isolated defects (21).

However, treatment is still highly complicated, if the cartilage defect or arthrotic damage extends over two or more compartments. Moreover, there are still no surgical treatment options for the tibia.

And various questions remain open, i.e. what happens, if an active working patient suffers from arthrosis? What happens, if a patient at a more advanced age (> 45 years) suffers from cartilage defects? What happens, if a socially deprived patient is affected?

Chondrocyte transplantation and mosaic graft procedures are not indicated in these cases and microfracturing according to Staedman would be the only option (32).

Besides symptomatic conservative measures, such as medication treatment associated with various adverse events, the only remaining possibility for patients is to significantly reduce their physical activity. The final alternative would be waiting for a total knee arthroplasty.

Arthrosis often makes the attending physician feel quite helpless.

The need for new surgical treatment options that are effective and comparatively inexpensive has become more urgent than ever and the implantation of carbon pins seems to be an interesting option. Carbon fibre tissue has now been used for almost 20 years. This material is manufactured from pure carbon fibres using a specific weaving process that has been subjected to extensive research (6, 23, 24, 26).

Fundamental work on the use of carbon pins in human joints has been done by R.J. Minns. In his first experiments Minns found out that the carbon fibre material induces the formation of a targeted tissue parallel to the carbon fibre bundle extending over the bone defect.

He concluded that the carbon fibre implants promote a successful mechanical and structural repair in osteoarthrotic rabbit knees up to 26 weeks after implantation. Moreover, he found out that the carbon material can be used as a prosthetic material for the reconstruction of osteoarthrotic joint surfaces (27).

In 1987, he published another study on carbon implants. "Carbon pins lead to a dense and well-structured matrix of fibrous tissue in the knee that is able to create a new biological and functioning surface." In 1989, trend-setting publications by D.S. Muckle and R.J. Minns followed. They reported on Carbon pads. The authors chose to use carbon in its pure form, as it obviously does not react with living tissue, especially as compared to other materials like silicone, nylon, polytetrafluorethylene, and other materials. The results of this study were also very promising. The carbon pads were filled with structurally strong and stable fibrous tissue and did not provoke a synovial reaction. In a simultaneous patient study, a satisfactory reconstruction of the surface was observed in 77% of the patients without synovitis. The authors concluded that carbon pads can lead to a satisfactory therapy of localised particular defects (29).

These results were confirmed in another study (25). The rabbit tests showed that woven carbon material promotes tissue ingrowth resulting in a histologically sound and solid replacement surface in the defect zones.