Computer-assisted revision of total knee arthroplasty.

Revision total knee prosthesis still remains a difficult procedure. Particularly, challenging is the restoration of the joint line to a normal position and the attainment of correct lower limb alignment and healthy bone support for the implants. Computer assistance improves accuracy during the implantation of primary total knees. The goal of this study was to evaluate the usefulness of computer assisted surgery (CAS) in total knee prosthesis revision. We revised 15 NKII total knee arthroplasties with the Navitrack system and compared the mechanical alignment and the joint line level on pre- and postoperative radiographs. After revision, the joint line position was restored. The knee with the revision prosthesis was aligned in the frontal plan with implants fixed perpendicularly to the mechanical axis. It is possible to correctly revise knee prosthesis with computer assistance only and without having to use a conventional ancillary. We had a permanent control of the joint line position and have performed the revision surgery following the same steps as in a primary implantation.