Knee joint prosthesis with a long service life

Profile

• What was needed: iglidur J guide rings from the iglidur product range
• Requirements: The solution was to be able to absorb high radial forces, have low wear and tear, and allow easy assembly.
• Industry: medical equipment
• Success for the customer: The iglidur guide ring allows all PTFE guide band installation work steps to be eliminated. They are simply clipped onto the piston, and assembly costs are reduced. Knee joint functionality, quality, and service life are increased. The important sliding properties are also greatly improved.

Problem

The PTFE guide band used so far has some disadvantages. One main problem is how to handle the PTFE guide band. This is supplied as a coil and must be cut to length in the first operation. This can result in different cutting dimensions, whereby a guide band that is too long may have to be shortened again so that it fits into the guide band groove. When cutting to size, the band may be crushed at the cutting edge, widening the height to such an extent that the band no longer fits into the groove. In this case, the band must be additionally trimmed. After cutting to length, the PTFE strips are packed and stored. Before the belts are installed, they are wound by means of a device to give them a curved shape. In use, however, the high abrasion of the PTFE guide band causes problems in long-term use.

Solution

The iglidur J guide ring from the iglidur product range serves as a guide for the upper and lower pistons in the pneumatic cylinder in the prosthetic applications, especially in pneumatic knee joints. It absorbs radial forces and provides the pistons with a lightweight, low-friction guide that influences the joint's swing phase.
The iglidur J guide ring allows all PTFE guide band work installation steps to be eliminated. It can be clipped onto the piston quickly and easily, greatly facilitating piston ring mounting. This reduces manufacturing costs (assembly costs), which has a positive effect on the overall price of the pneumatic knee joint. Successful tests on the iglidur J guide rings showed hardly any noticeable wear, meaning that the knee joint's functionality, quality, and service life are increased. The important sliding properties are also greatly improved.