title: On stabilization of loosened hip stems via cement injection into osteolytic cavities.
abstract: BACKGROUND
  Cement injection into osteolytic areas around the cement mantle is a technique for refixation of loose hip implants for patients who cannot undergo standard revision surgery. Preliminary clinical results show the improvement in walking distance, patients' independence and pain relief.
  
  
  METHODS
  In this study, we use a detailed finite element model to analyze whether cement injection into osteolytic areas contributes to the overall implant stability. We study the effect of various factors, like location and size of osteolytic areas, interface conditions and bone stiffness on bone-cement relative motion.
  
  
  RESULTS
  Presented results demonstrate that the procedure is most effective for the osteolytic areas located in the proximal region of the femur, while factors like a thin layer of residual fibrous tissue around the injected cement, that was not removed during the surgery, combined with reduced bone stiffness reduce the efficiency of the procedure.
  
  
  CONCLUSIONS
  Cement injection is able to stabilize loosened hip prostheses. However, it is important to remove the fibrous tissue layer completely, as even a thin layer will negatively influence stabilization. We will focus our research efforts on developing fibrous tissue removal techniques in order to optimize this minimally invasive treatment.
authors.affiliation: Biomechanics and Imaging Group, Department of Orthopaedics, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands. andriy.andreykiv@gmail.com
authors.forename: A
authors.initials: A
authors.lastname: Andreykiv
authors.forename: D
authors.initials: D
authors.lastname: Janssen
authors.forename: R G H H
authors.initials: RG
authors.lastname: Nelissen
authors.forename: E R
authors.initials: ER
authors.lastname: Valstar
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods; D001843:Bone Cements / Q000737:chemistry*; D001842:Bone and Bones / Q000473:pathology; D002484:Cementation / Q000379:methods; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006615:Hip / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D010014:Osteolysis; D012086:Reoperation; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D001843:Bone Cements