TY - GEN

T1 - Optical inspection system for implants

AU - Denkena, Berend

AU - Acker, Wolfram

PY - 2006/4/14

Y1 - 2006/4/14

N2 - Hip and knee prostheses are complex products with high quality standards. The aim is to reproduce the behavior of a natural joint. This can be achieved by using a hard and a soft component. The research project "Optical Geometry Acquisition of Medical Implants and Prostheses", short "OptiGIP", explores methods for an automated quality assurance included in the production chain of these components. The approach is divided in two sections, a three dimensional and a two dimensional measurement technique. First a stripe projection method is used to produce a three dimensional model of the component. This model can be used to verify the geometry of the component. Furthermore it enables a new examination method, the Model-Based RSA, which is used to explore the effect of loosening. A late loosening of the components within the bones is the most important quality criterion for a successful implantation. The second part of described measurement method aims at a reduction of an early loosening of the prosthesis. Even very small scratches on the prosthesis's surface can have an impact on an early loosening because of friction between the soft and hard surface. Scratches produce bigger particles of the soft component than an undamaged surface would do. Recent research activities show that these bigger particles have an influence on an early loosening mechanism. The two-dimensional measurement checks the quality of the surface of the hard component of the implant. The approach is to use an extended dark field method. The prosthesis is illuminated from various angles producing a sequence of images. These images are filtered to distinguish between reflections from scratches and direct reflections. A combination of the filtered images shows the scratches.

AB - Hip and knee prostheses are complex products with high quality standards. The aim is to reproduce the behavior of a natural joint. This can be achieved by using a hard and a soft component. The research project "Optical Geometry Acquisition of Medical Implants and Prostheses", short "OptiGIP", explores methods for an automated quality assurance included in the production chain of these components. The approach is divided in two sections, a three dimensional and a two dimensional measurement technique. First a stripe projection method is used to produce a three dimensional model of the component. This model can be used to verify the geometry of the component. Furthermore it enables a new examination method, the Model-Based RSA, which is used to explore the effect of loosening. A late loosening of the components within the bones is the most important quality criterion for a successful implantation. The second part of described measurement method aims at a reduction of an early loosening of the prosthesis. Even very small scratches on the prosthesis's surface can have an impact on an early loosening because of friction between the soft and hard surface. Scratches produce bigger particles of the soft component than an undamaged surface would do. Recent research activities show that these bigger particles have an influence on an early loosening mechanism. The two-dimensional measurement checks the quality of the surface of the hard component of the implant. The approach is to use an extended dark field method. The prosthesis is illuminated from various angles producing a sequence of images. These images are filtered to distinguish between reflections from scratches and direct reflections. A combination of the filtered images shows the scratches.

KW - Aseptic loosening

KW - Dark field method

KW - Optical measurement

KW - Quality assurance

KW - Radio stereo metric analysis

UR - http://www.scopus.com/inward/record.url?scp=33745132140&partnerID=8YFLogxK

U2 - 10.1117/12.662551

DO - 10.1117/12.662551

M3 - Conference contribution

AN - SCOPUS:33745132140

SN - 0819462470

SN - 9780819462473

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Biophotonics and New Therapy Frontiers

PB - SPIE

CY - Bellingham, Wash.

T2 - SPIE Photonics Europe

Y2 - 3 April 2006 through 7 April 2006

ER -