ISO 16087 pdf download

ISO 16087 pdf download Implants for surgery — Roentgen stereophotogrammetric analysis for the assessment of migration of orthopaedic implants
1 Scope
This International Standard provides requirements for the clinical assessment of migration of orthopaedic implants with roentgen stereophotogrammetric analysis (RSA).
2? Terms? and? definitions
For the purposes of this document, the following terms and definitions apply.
2.1
absolute movement
movement of a rigid body relative to a fixed reference rigid body
2.2
accuracy
closeness of agreement between a measured quantity value and a true quantity value of a measurand
2.3
bias
estimate of a systematic measurement error
2.4
biplanar technique
RSA technique where two X-ray cassettes/films/sensors are set at an angle to each other
2.5
calibration cage
calibration box
reference frame used to create a three-dimensional coordinate system, with definition of position and orientation, and to determine the position of the two roentgen foci
2.6
condition number
calculated number used to assess the distribution of markers
Note 1 to entry: High condition numbers indicate poor marker distribution, while low condition numbers indicate appropriate marker distribution.
Note 2 to entry: See Annex A, which establishes the methodology to determine the condition number associated with the marker distribution.
2.7
crossing line error
shortest distance between the two X-rays projecting the centre of a marker in the two RSA images
2.8
double examinations
two RSA examinations of the same patient within an interval of several minutes
2.9
helicalaxis
screw axisinstantaneous axis about which the decomposition of the motion of an object from one position toanother has a translation along and a rotation about a single axis
2.10
marker
small diameter biocompatible metal sphere having a precise size and shape used as landmarkNote 1 to entry: Spherical tantalum markers serve as well-defined landmarks
Note 2 to entry: The diameter is commonly s 1 mm.
2.11
maximum total point motionMTPM
length ofthe translation vector ofthe marker orvirtual marker in arigid bodythathas the greatestmigrationNote 1 to entry: It can only have positive values, and is not normally distributed
2.12
mean error ofrigid body fitting
rigid body errormeasure indicating the mean change of relative positions of markers (in the same object) over timecompared to the initial, reference configuration
Note 1 to entry: Annex A establishes the methodology to determine the mean error associated with the change ofrelative positions of markers.
2.13
migrationchange in position and orientation of an implant relative to the host bone assessed between follow-up examinations
2.14
model-basedRSA
RSA technique in which the position and orientation of an implant is assessed by matching a virtuaprojection ofa three-dimensional model ofthe implantto the actualradiographic projection ofthe implant