title: Total arthroplasty of basal thumb joint with Elektra prothesis: an in vitro analysis.
abstract: The reported outcomes of the Elektra thumb carpo-metacarpal joint implant have been very variable. This study evaluates the influence of daily cyclic loads and the type of the screw-fit cup insertion technique in the trapezium, with and without prior threading, on the structural bone behaviour. The study was performed experimentally to predict initial implant stability and cortical bone strains. Computational models were developed to assess the structural cancellous bone behaviour. The use of Elektra implant considerably changed the bone strain behaviour compared with the intact joint. This may be associated with risks of cancellous bone fatigue failure due to overload, particularly in the trapezium. The joint load magnitude has a more important structural role than that of the screw-fit cup insertion technique. Limiting the magnitude of thumb loads after arthroplasty may contribute positively to the longevity of this procedure.
  
  
  METHODS
  V.
authors.affiliation: 1 Mechanical Engineering Department, University of Aveiro, Aveiro, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Completo
authors.affiliation: 2 Orthopaedics Department, Coimbra University Hospital, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Nascimento
authors.affiliation: 1 Mechanical Engineering Department, University of Aveiro, Aveiro, Portugal.
authors.forename: F
authors.initials: F
authors.lastname: Neto
mesh_terms: D019643:Arthroplasty, Replacement; D001863:Bone Screws; D052737:Carpometacarpal Joints; D020342:Finite Element Analysis; D006801:Humans; D007595:Joint Prosthesis; D010003:Osteoarthritis / Q000601:surgery*; D011475:Prosthesis Failure; D013933:Thumb; D046509:Tissue Culture Techniques; D051222:Trapezium Bone / Q000601:surgery*; D016474:Weight-Bearing
keywords: Carpometacarpal joint; finite element models; principal cortex strains; stress-shielding; uncemented trapeziometacarpal prosthesis