iglidur® instead of metal bearings in knee joint prostheses

• What was needed: Bearings made of iglidur ® W300 and iglidur ® Q
• Requirements: Previous metal bearings were susceptible to dust and dirt, exhibited high clearance, fretting corrosion and noise during movement. The new solution should avoid this, be lightweight and have a good price-performance ratio
• Industry: Medical technology, prostheses
• Success for the customer: iglidur® W300 enables bearings with a particularly long service life, low coefficient of friction and extremely high abrasion resistance. iglidur® Q bearings, on the other hand, are particularly suitable for high loads. The prosthesis has become lighter and smoother at the same time. The user now has to visit the orthopaedic mechanic much less frequently.

Otto Bock Health Care GmbH, a leading global provider of orthopaedic technology, has been offering high-quality and technologically advanced products and services for people with limited mobility for almost 90 years. For one of the specialist's products - the "3R60 EBS" knee joint prosthesis (EBS: Ergonomic Balenced Stride) - a new solution was to be found for the various bearing points. Until now, the manufacturer had relied on needle and bronze bearings, but these proved to be susceptible to dust and dirt and, with increasing clearance, developed disturbing noises and fretting corrosion during small swivelling movements. The latter could even endanger the prosthesis wearer by blocking the axis. An improved design was therefore to be found that does not require metal. However, the new solution also had to fulfil other requirements, such as absolute maintenance and zero clearance as well as low wear. In addition, they should run quietly, absorb shocks and have a good price-performance ratio.

The plain bearings of the iglidur ® W300 and iglidur ® Q type, which replace the previous needle and bronze plain bearings, are now located at all bearing points of the artificial knee joint.
All representatives of the iglidur ® W300 family ensure a particularly long service life, low coefficient of friction and extremely high abrasion resistance. They are also suitable for soft shafts and are resistant to chemicals. iglidur® W300 has a very high compressive strength despite its high flexibility.
The iglidur ® Q bearings, on the other hand, are particularly recommended for very high loads, under which they exhibit by far the best wear resistance among the iglidur® materials. From a radial load of 25 MPa, they even outperform plain bearings made from the highly abrasion-resistant iglidur® W300. Special solid lubricants distributed extremely finely in the material ensure that maintenance-free dry operation is guaranteed at any load. Under the maximum permissible load of 100 mPa, the elastic deformation at room temperature is less than 3 per cent.
The use of plastic bearings has increased the service life of the prostheses and minimised clearance and noise. At the same time, the prosthesis has become lighter and easier to move. The user now has to visit the orthopaedic technician much less often.