Maintenance-free knee joint prosthesis

Profile

• What was needed: iglidur J guide rings
• Requirements: They were looking for a wear-free and maintenance-free guidance for the piston in the joint, which would also transfer the lateral forces that occur during the swing phase from the pneumatic pistons to the pneumatic cylinder.
• Industry: medical equipment
• Success for the customer: Since replacing the PTFE guide bands originally used with iglidur J guide rings, the complaint rate for leaking pneumatics due to worn piston guides has fallen to almost zero. Installation of the guide rings is also effortless and time-saving compared to the previous solution.

Problem

During the development of the new 3R106-PRO pneumatic knee joint, initial patient tests showed that when walking quickly at the start of the forward movement of the prosthetic leg, the air spring in the prosthetic knee joint was too strong and made walking appear unphysiological. The leg shoots forwards too much and can then no longer be slowed down effectively enough.
In order to transfer the transverse forces that occur during the swing phase from the pneumatic pistons to the pneumatic cylinder that forms the lower part of the knee joint, a solution should be found that simultaneously guides the piston in the pneumatic prosthetic knee joints.
Previously, this task was performed by PTFE guide belts, but these led to a high complaint rate due to leaking pneumatics as a result of worn piston guides.

Solution

Since the end of 2010, Ottobock has been using iglidur J guide rings in its pneumatic prosthetic knee joints for guidance with great success. They transfer the lateral forces that occur during the swing phase from the pneumatic pistons to the pneumatic cylinder with little friction and wear.
Since replacing the PTFE guide belts originally used, the number of complaints about leaking pneumatics due to worn piston guides has fallen to almost zero.
Another advantage of the iglidur J guide rings is the significantly simplified assembly. Whereas PTFE guide bands still had to be cut to length individually, the guide rings can now be clipped into the appropriate piston groove effortlessly and quickly.
Thanks to the special design of the iglidur J guide ring, a cost-effective and reliable rapid venting function could also be integrated into the knee joint. This additional function makes the gait pattern appear much more harmonious, especially when changing from a medium to a high walking speed