title: A Toroidal Probe for Measuring Surgically Exposed Joint Centers.
abstract: Maintaining the hip center can improve the success of a total hip arthroplasty. A novel probe design, based on mating a toroid with a sphere, was used for kinematic measurements of the femoral head center and implant center in a pre-clinical study of hip joints. In an electromagnetically tracked implementation tested in a laboratory environment, the device measured a spherical center to within 1.2±0.2 mm in a technical validation. Applied to a plastic model of a cadaveric femur, the center of the femoral head was measured to 1.8±0.4 mm and the implant was measured to within 1.5±0.5 mm. Because leg length changes and offset changes in conventional hip arthroplasty can be as much as 16 mm, this device has relatively high accuracy that may improve implant localization for the hip.
authors.affiliation: Dept. of Mechanical & Materials Engineering, Queen's University, Kingston, ON, CA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Rasquinha
authors.affiliation: Dept. of Mechanical & Materials Engineering, Queen's University, Kingston, ON, CA.
authors.forename: Kate S M
authors.initials: KS
authors.lastname: Loe
authors.affiliation: School of Computing, Queen's University, Kingston, ON, CA.
authors.forename: Andrew W L
authors.initials: AW
authors.lastname: Dickinson
authors.affiliation: Dept. of Surgery, Queen's University, Kingston, ON, CA.
authors.forename: John F
authors.initials: JF
authors.lastname: Rudan
authors.affiliation: Dept. of Mechanical & Materials Engineering, Queen's University, Kingston, ON, CA.
authors.forename: Randy E
authors.initials: RE
authors.lastname: Ellis
mesh_terms: D053587:Arthrometry, Articular / Q000295:instrumentation*; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007430:Intraoperative Care / Q000295:instrumentation*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D017755:Prosthesis Fitting / Q000295:instrumentation*; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers