ASTM F1223 Restriction of the range of motion (ROM)
We offer you a characterization of the restriction of the range of motion of knee endoprostheses regarding the translational and rotational degrees of freedom according to ASTM F1223. For this purpose, either the tibia or the femoral component is firmly clamped to the test device while the other side remains movable. The stability of your individual knee endoprosthesis is assessed by five tests:
- anterior-posterior tensile test:
With an applied joint load of 710 N, a gradual displacement is applied anteriorly and posteriorly to the movable component until a dislocation is reached.
- medial-lateral shear test:
With an applied joint load of 710 N, a gradual displacement is applied medially and laterally to the movable component until a dislocation is reached.
- rotation stability test:
With an applied joint load of 710 N, a gradual rotation is applied to the movable component until a dislocation or a torque of 25 Nm or a torsion angle of 20° is reached.
- distraction test:
A flexion angle is set, which is most likely to distract. Subsequently, a gradual load is applied until a level of 44.5 N or a previous distraction is reached.
- valgus-varus rotation test (if the tested implant has a varus-valgus restriction):
The flexion angle of ASTM F2083 is used and a joint load of 45 N is applied. Subsequently, a varus/valgus torque is applied via a medial/lateral load until there is a contact between the tibial post and the opposite side.
These tests can also be carried out with mobile bearings. Therefore, they have to be fixed to the tibial components.