title: Revision total knee arthroplasty: a comparison of postoperative leg alignment after computer-assisted implantation versus the conventional technique.
abstract: Accurate reconstruction of leg alignment is one important factor for long-term survival in total knee arthroplasty (TKA). Recent developments in computer-assisted surgery focused on systems improving TKA. The aim of the study is to compare the results of computer-assisted revision TKA with the conventional technique. We hypothesize that a significantly better leg alignment and component orientation is achieved when using a navigation system for revision TKA. In a prospective study, two groups of 25 revision TKAs each were operated on using either a CT-free navigation system or the classical surgeon-controlled technique. The postoperative leg alignment was analysed on long-leg coronal and lateral X-rays. The mechanical limb axis was significantly better in the navigation-based group. Twenty-three patients (92%) in the computer-assisted group had a postoperative leg axis between 3 degrees varus/valgus deviation, while 19 patients (76%) in the conventional group had a comparable result (p<0.05). Further, significant differences were seen for the coronal orientation of the femoral component. Computer-assisted revision TKA leads to a superior restoration of leg alignment compared with the conventional technique. Particularly the real-time presentation of the actual leg axis and the flexion and extension gaps is useful in revision TKA. Potential benefits in long-term outcome and functional improvement require additional investigation.
authors.affiliation: Department of Orthopaedic Surgery, University of Regensburg, Postbox 100662, 93042 Regensburg, Germany. lars.perlick@klinik.uni-regensburg.de
authors.forename: Lars
authors.initials: L
authors.lastname: Perlick
authors.forename: Holger
authors.initials: H
authors.lastname: Bäthis
authors.forename: Carsten
authors.initials: C
authors.lastname: Perlick
authors.forename: Christian
authors.initials: C
authors.lastname: Lüring
authors.forename: Markus
authors.initials: M
authors.lastname: Tingart
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001168:Arthritis / Q000601:surgery; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001837:Body Weights and Measures; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000601:surgery; D007719:Knee Joint / Q000601:surgery; D007866:Leg; D008297:Male; D008875:Middle Aged; D038361:Neuronavigation; D011446:Prospective Studies; D011475:Prosthesis Failure; D012086:Reoperation; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome