Glossary

Events such as patient death mean that a complete follow-up from the index operation to its subsequent revision is not possible. As far as the EPRD is concerned such censoring events may also include patients that are lost to further follow-up as a result of changing health insurer. In such cases arthroplasties are considered to have reached a premature end of service life, but are not considered to have failed.

Implant components that consist of a zirconium alloy substrate and a ceramic surface modification - oxidised zirconium alloy.

Implant components that have been coated with ceramics (e.g. titanium nitride).

Patellar resurfacing following primary bicondylar knee arthroplasty on the same joint affected by "normal" progression of the disease, is a complementary operation, rather than a revision operation.

Interval that contains the true value within a specified probability range (confidence level)

Knee replacements are characterised by their level of constraint (stabilisation). In this report, we define “unconstrained” knee systems as cruciate-retaining, cruciate-retaining/sacrificing, pure cruciate sacrificing and also posterior stabilised systems without varus-valgus stabilisation. Varus-valgus stabilised and (rigid/rotational) hinge systems are considered as "constrained".

Design preserving the posterior cruciate ligament without constraining knee motion/kinematic.

The design is suitable for both a cruciate ligament-retaining or a replacement procedure.

Design replacing the posterior cruciate ligament with kinematic, which partially permits a limited relative motion in all three planes.

See: "Acetabular component".