title: Similar migration in computer-assisted and conventional total knee arthroplasty.
abstract: Background and purpose - Computer-assisted surgery (CAS) in total knee arthroplasty (TKA) has been used in recent years in the hope of improving the alignment and positioning of the implant, thereby achieving a better functional outcome and durability. However, the role of computer navigation in TKA is still under debate. We used radiostereometric analysis (RSA) in a randomized controlled trial (RCT) to determine whether there are any differences in migration of the tibial component between CAS- and conventionally (CONV-) operated TKA. Patients and methods - 54 patients (CAS, n = 26; CONV, n = 28) with a mean age of 67 (56-78) years and with osteoarthritis or arthritic disease of the knee were recruited from 4 hospitals during the period 2009-2011. To estimate the mechanical stability of the tibial component, the patients were examined with RSA up to 24 months after operation. The following parameters representing tibial component micromotion were measured: 3-D vector of the prosthetic marker that moved the most, representing the magnitude of migration (maximum total point motion, MTPM); the largest negative value for y-translation (subsidence); the largest positive y-translation (lift-off); and prosthetic rotations. The precision of the RSA measurements was evaluated and migration in the 2 groups was compared. Results - Both groups had most migration within the first 3 months, but there was no statistically significant difference in the magnitude of the migration between the CAS group and the CONV group. From 3 to 24 months, the MTPM (in mm) was 0.058 and 0.103 (p = 0.1) for the CAS and CON groups, respectively, and the subsidence (in mm) was 0.005 and 0.011 (p = 0.3). Interpretation - Mean MTPM, subsidence, lift-off, and rotational movement of tibial trays were similar in CAS- and CONV-operated knees.
authors.affiliation: a Lovisenberg Diakonale Hospital , Oslo.|b The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery , Haukeland University Hospital , Bergen.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Petursson
authors.affiliation: b The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery , Haukeland University Hospital , Bergen.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Fenstad
authors.affiliation: b The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery , Haukeland University Hospital , Bergen.|c Department of Clinical Medicine , Institute of Medicine and Dentistry, University of Bergen , Bergen.|d Haugesund Hospital , Haugesund.
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Gøthesen
authors.affiliation: e Orthopaedic Research Center, Trondheim University Hospital , Trondheim.
authors.forename: Kristin
authors.initials: K
authors.lastname: Haugan
authors.affiliation: b The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery , Haukeland University Hospital , Bergen.|c Department of Clinical Medicine , Institute of Medicine and Dentistry, University of Bergen , Bergen.
authors.forename: Gro Sævik
authors.initials: GS
authors.lastname: Dyrhovden
authors.affiliation: c Department of Clinical Medicine , Institute of Medicine and Dentistry, University of Bergen , Bergen.
authors.forename: Geir
authors.initials: G
authors.lastname: Hallan
authors.affiliation: f Department of Orthopaedics , Oslo University Hospital, Ullevål , Oslo , Norway.
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Röhrl
authors.affiliation: a Lovisenberg Diakonale Hospital , Oslo.
authors.forename: Arild
authors.initials: A
authors.lastname: Aamodt
authors.affiliation: g Department of Surgical and Perioperative Sciences , Orthopaedics, Umeå University , Umeå , Sweden.
authors.forename: Kjell G
authors.initials: KG
authors.lastname: Nilsson
authors.affiliation: b The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery , Haukeland University Hospital , Bergen.|c Department of Clinical Medicine , Institute of Medicine and Dentistry, University of Bergen , Bergen.
authors.forename: Ove
authors.initials: O
authors.lastname: Furnes
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*