The latest in a series of ASTM International standards developed for the characterization of mobile bearing knees prior to implementation has now been approved by ASTM International Committee F04 on Medical and Surgical Materials and Devices. The new standard, ASTM F2777, Test Method for Evaluating Knee Bearing (Tibial Insert) Endurance and Deformation Under High Flexion, is under the jurisdiction of Subcommittee F04.22 on Arthroplasty.

According to Leslie Gilbertson, L. Gilbertson Consulting LLC, and vice chairman, F04.22, ASTM F2777 and the three previously approved standards are designed to address the possible failure mechanisms of mobile knee systems, although in some instances they would also be used for fixed bearing knees.

“A group of orthopedic company representatives was brought together under the Orthopedic Surgical Manufacturers Association to decide on the appropriate test methodologies based on their individual experiences,” says Gilbertson. The resulting test methods have now all become ASTM standards.

In addition to ASTM F2777, the other three standards in the series are:

- ASTM F2722, Test Method for Evaluating Mobile Bearing Knee Tibial Baseplate Rotational Stops;
- ASTM F2723, Test Method for Evaluating Mobile Bearing Knee Tibial Baseplate/Bearing Resistance to Dynamic Disassociation, and
- ASTM F2724, Test Method for Evaluating Mobile Bearing Knee Dislocation.

“The concept of a mobile bearing knee system is that it can better approximate the complicated flexion, translation and interior exterior rotation of the natural knee,” says Gilbertson.

According to Gilbertson, primary users of ASTM F2777 and the other standards will be implant companies seeking to develop new mobile bearing knee systems and compare them to other knee systems with no clinical histories. “Academics and surgeons may also be interested in running these tests to decide on which knee performs best,” notes Gilbertson.

F04.22 welcomes all interested parties to take part in its activities and is particularly interesting in the participation of orthopedic companies and academic laboratories in upcoming round robin testing for ASTM F2777.

To purchase ASTM standards, visit www.astm.org and search by the standard designation number, or contact ASTM Customer Relations (phone: 610-832-9585; https://www.astm.org/contact/). For more information on becoming an ASTM member, visit www.astm.org/JOIN.

ASTM Committee F04 Next Meeting: May 17-20, 2011, May Committee Week, Anaheim, Calif.
Technical Contact: Leslie Gilbertson, L. Gilbertson Consulting LLC, Warsaw, Ind., Phone: 574-377-0561; leslie.gilbertson@comcast.net
ASTM Staff Contact: Daniel Schultz, Phone: 610-832-9716; dschultz@astm.org
ASTM PR Contact: Barbara Schindler, Phone: 610-832-9603; bschindl@astm.org

Release #8757