title: Cemented tibial component fixation performs better than cementless fixation: a randomized radiostereometric study comparing porous-coated, hydroxyapatite-coated and cemented tibial components over 5 years.
abstract: BACKGROUND
  The question whether the tibial component of a total knee arthroplasty should be fixed to bone with or without bone cement has not yet been definitely answered. We studied movements between the tibial component and bone by radiostereometry (RSA) in total knee replacement (TKR) for 3 different types of fixation: cemented fixation (C-F), uncemented porous fixation (UC-F) and uncemented porous hydroxyapatite fixation (UCHA-F).
  
  
  METHODS
  116 patients with osteoarthrosis, who had 146 TKRs, were included in 2 randomized series. The first series included 86 unilateral TKRs stratified into 1 of the 3 types of fixation. The second series included 30 patients who had simultaneous bilateral TKR surgery, and who were stratified into 3 subgroups of pairwise comparisons of the 3 types of fixation.
  
  
  RESULTS
  After 5 years 2 knees had been revised, neither of which were due to loosening. 1 UCHA-F knee in the unilateral series showed a large and continuous migration and a poor clinical result, and is a pending failure. The C-F knees rotated and migrated less than UC-F and UCHA-F knees over 5 years. UCHA-F migrated less than UC-F after 1 year.
  
  
  CONCLUSIONS
  Cementing of the tibial component offers more stable bone-implant contact for 5 years compared to uncemented fixation. When using uncemented components, however, there is evidence that augmenting a porous surface with hydroxyapatite may mean less motion between implant and bone after the initial postoperative year.
authors.affiliation: Department of Orthopedicsy, Malmö University Hospital, SE-205 02 Malmö, Sweden. ake.carlsson@orto.mas.lu.se
authors.forename: Ake
authors.initials: A
authors.lastname: Carlsson
authors.forename: Anders
authors.initials: A
authors.lastname: Björkman
authors.forename: Jack
authors.initials: J
authors.lastname: Besjakov
authors.forename: Ingemar
authors.initials: I
authors.lastname: Onsten
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001843:Bone Cements; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000601:surgery; D016062:Porosity; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D012086:Reoperation; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D001843:Bone Cements; D020099:Coated Materials, Biocompatible; D017886:Durapatite