title: Effect of anterior-posterior and internal-external motion restraint during knee wear simulation on a posterior stabilised knee design.
abstract: The objective of our study was to examine the effect of biphaseal AP translation and IE rotation restraint, using a system defined specifically for posterior stabilised knee designs, on wear, kinematics and particle release in comparison to linear motion restraint as required by the established ISO 14243-1:2002(E) protocol. In the ISOlinear groups, an AP motion restraint of 30 N/mm and an IE rotation restraint of 0.6 Nm/° were applied in the knee wear simulation. In the ISOgap biphaseal groups with PCL sacrificing implants, the restraining AP force was zero in a ±2.5mm range with, externally, a constant of 9.3N/mm applied proportionally to the AP translation of the tibia plateau, whereas the restraining IE torque was zero in a ±6° range with, externally, a constant of 0.13 Nm/° applied proportionally to the IE rotation of the tibia plateau. Using the ISOgap biphaseal protocol on a posterior stabilised knee design, we found an increase of 41% in AP translation and of 131% in IE rotation, resulting in a 3.2-fold higher wear rate compared to the results obtained using the ISOlinear protocol. Changes in AP translation and IE rotation ligament motion restraints have a high impact on knee joint kinematics and wear behaviour of a fixed bearing posterior stabilised knee design.
authors.affiliation: Aesculap AG, Research & Development, Tuttlingen, Germany. thomas.grupp@aesculap.de
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Grupp
authors.forename: Khaled J
authors.initials: KJ
authors.lastname: Saleh
authors.forename: William M
authors.initials: WM
authors.lastname: Mihalko
authors.forename: Martin
authors.initials: M
authors.lastname: Hintner
authors.forename: Bernhard
authors.initials: B
authors.lastname: Fritz
authors.forename: Christoph
authors.initials: C
authors.lastname: Schilling
authors.forename: Jens
authors.initials: J
authors.lastname: Schwiesau
authors.forename: Christian
authors.initials: C
authors.lastname: Kaddick
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D007720:Knee Prosthesis; D008422:Materials Testing / Q000379:methods*; D009038:Motion; D011474:Prosthesis Design