title: Comparable Stability of Cemented vs Press-Fit Placed Stems in Revision Total Knee Arthroplasty With Mild to Moderate Bone Loss: 6.5-Year Results From a Randomized Controlled Trial With Radiostereometric Analysis.
abstract: Short-term stability after revision total knee arthroplasty (TKA) with either fully cemented or hybrid-placed implants is comparable. Interestingly, implant micromotion >1 mm/degree occurred with both techniques which might increase the risk of loosening in the midterm or long-term. Therefore, the present study investigated midterm stability and clinical results of fully cemented vs hybrid-placed revision TKA, with mild to moderate bone loss, using radiostereometric analysis (RSA).
  
  
  
  This study involves the prolonged follow-up of a previous randomized controlled trial. RSA images taken at baseline, 6 weeks, 3 and 6 months, and 1, 2 and 6.5 years of follow-up were analyzed. Stability of the femoral and tibial implants was evaluated using total translation and rotation, based on the micromotion determined with model-based RSA.
  
  
  
  Of the 30 patients who completed the 2-year follow-up in the original randomized controlled trial, 23 (12 cement, 11 hybrid) were available for follow-up at 6.5-year (range 5.4-7.3). There were no differences in median total translation and rotation of the femoral and tibial components between the 2 groups, and none of the clinical scores differed between the groups. Interestingly, in the group with cemented stems, 5 tibia implants showed >1 mm/degree micromotion compared to none in the hybrid group.
  
  
  
  There was no difference in median micromotion and clinical outcome between fully cemented and hybrid-placed revision TKA 6.5 years postoperatively. Two femur components showed progressive migration over time whereas tibia components migrate especially in the first year followed by a stable situation. Whether this will lead to loosening and re-revisions remains to be investigated.
authors.affiliation: Department of Research, Sint Maartenskliniek, Nijmegen, The Netherlands.
authors.forename: Nienke M
authors.initials: NM
authors.lastname: Kosse
authors.affiliation: Department of Orthopedic Surgery, Sint Maartenskliniek, Nijmegen, The Netherlands.
authors.forename: Gijs G
authors.initials: GG
authors.lastname: van Hellemondt
authors.affiliation: Department of Orthopedic Surgery, Sint Maartenskliniek, Nijmegen, The Netherlands.
authors.forename: Ate B
authors.initials: AB
authors.lastname: Wymenga
authors.affiliation: Department of Research, Sint Maartenskliniek, Nijmegen, The Netherlands.
authors.forename: Petra J C
authors.initials: PJ
authors.lastname: Heesterbeek
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D001843:Bone Cements; D005260:Female; D005269:Femur / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D007720:Knee Prosthesis / Q000009:adverse effects / Q000706:statistics & numerical data*; D008297:Male; D011474:Prosthesis Design; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis; D012399:Rotation; D013977:Tibia / Q000601:surgery
chemical_list: D001843:Bone Cements
keywords: RSA (radiostereometric analysis); cemented fixation; hybrid fixation; revision total knee arthroplasty; stems