title: Concept, design and fabrication of smart orthopedic implants.
abstract: Extensive clinical experience has been built up using orthopaedic implants instrumented with strain gauges connected to a Wheatstone bridge by means of percutaneous leads. This research showed the medical relevance of the monitoring of the deformation of implants as a powerful tool to evaluate nursing and rehabilitation exercises, for tracing dangerous overloads and anticipating implant failure and also to observe the healing process. The IMPACT 3500 project focuses on the instrumentation of femoral implants with on board sensors: regular Benoist-Girard implants have been modified, to contain a 'sensing cell', and thoroughly tested in vitro and in vivo. The implant deformations are measured with resistive strain gauges, and the signal is transferred to a personal computer for processing and display, via a hard wired connection, or via a telemetry system. Two fully implantable wireless designs, called Linkstrain and Sealstrain, are powered from the outside by magnetic induction. As Sealstrain contains the whole telemetric system in its cavity, the highest miniaturization was required; this seriously deteriorates the efficiency of the inductive power link.
authors.affiliation: Service d'Orthopédie-Traumatologie, Cliniques Universitaires de Bruxelles, Hôpital Erasme, Brussels, Belgium. fburny@ulb.ac.be
authors.forename: F
authors.initials: F
authors.lastname: Burny
authors.forename: M
authors.initials: M
authors.lastname: Donkerwolcke
authors.forename: F
authors.initials: F
authors.lastname: Moulart
authors.forename: R
authors.initials: R
authors.lastname: Bourgois
authors.forename: R
authors.initials: R
authors.lastname: Puers
authors.forename: K
authors.initials: K
authors.lastname: Van Schuylenbergh
authors.forename: M
authors.initials: M
authors.lastname: Barbosa
authors.forename: O
authors.initials: O
authors.lastname: Paiva
authors.forename: F
authors.initials: F
authors.lastname: Rodes
authors.forename: J B
authors.initials: JB
authors.lastname: Bégueret
authors.forename: P
authors.initials: P
authors.lastname: Lawes
mesh_terms: D001672:Biocompatible Materials; D001860:Bone Plates; D002516:Ceramics; D003343:Corrosion; D005264:Femoral Fractures / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008422:Materials Testing; D008670:Metals; D008855:Microscopy, Electron, Scanning; D008991:Monitoring, Physiologic / Q000295:instrumentation; D019736:Prostheses and Implants; D011474:Prosthesis Design; D013057:Spectrum Analysis; D013193:Stainless Steel / Q000032:analysis; D013314:Stress, Mechanical; D013686:Telemetry / Q000295:instrumentation*; D016474:Weight-Bearing / Q000502:physiology
chemical_list: D001672:Biocompatible Materials; D008670:Metals; D013193:Stainless Steel