title: Biomechanical evaluation of different reconstructive techniques of proximal tibia in revision total knee arthroplasty: An in-vitro and finite element analysis.
abstract: BACKGROUND
  Bone loss and subsequent defects are often encountered in revision total knee arthroplasty. In particular, when the cortical rim of proximal tibia is breached, the surgical decision on the reconstructive options to be taken is challenging due to the variety of defects and the lack of data from clinical or experimental studies that can support it. The purpose of this study is to assess how different reconstructive techniques, when applied to an identical defect and bone condition, can be associated to dissimilar longevity of the revision procedure, and the role of a stem in this longevity.
  
  
  METHODS
  Proximal cortex strains and implant stability were measured in ten reconstructive techniques replicated with synthetic tibiae. The cancellous bone strains under each construct were assessed with finite element models which were validated against experimental strains.
  
  
  RESULTS
  The measured strains and stability showed that the proximal cortex is not immune to the different reconstructive techniques when applied to an identical defect. The largest cancellous strain differences between modular and non-modular techniques indicate a distinct risk between reconstructive techniques, associated to the supporting capacity of cancellous bone at long term.
  
  
  CONCLUSIONS
  The main finding of the present study is the observation that modular augments increases, on a long term basis, the potential risk of bone resorption relative to the non-modular techniques. In addition, the use of a press-fit stem in the scope of non-modular techniques can lead to improved stability and load transfer, which can contribute positively to the life expectancy of these techniques.
authors: Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal. completo@ua.pt
authors: A
authors: A
authors: Completo
authors: R
authors: R
authors: Duarte
authors: F
authors: F
authors: Fonseca
authors: J A
authors: JA
authors: Simões
authors: A
authors: A
authors: Ramos
authors: C
authors: C
authors: Relvas
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D020342:Finite Element Analysis; D006801:Humans; D066298:In Vitro Techniques; D007720:Knee Prosthesis; D008954:Models, Biological; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D019651:Plastic Surgery Procedures / Q000379:methods*; D012086:Reoperation; D013314:Stress, Mechanical; D013977:Tibia / Q000503:physiopathology / Q000601:surgery*