The bone cuts and ligament balance in total knee arthroplasty: The third way using computer assisted surgery

Abstract

Computer assisted orthopaedic surgery has become an important innovation in total knee arthroplasty (TKA) with very good clinical results [ 1 Dutton A.Q. Yeo S.J. Yang K.Y. Lo N.N. Chia K.U. Chong H.C. Computer-assisted minimally invasive total knee arthroplasty compared with standard total knee arthroplasty. A prospective, randomized study. J Bone Joint Surg Am. 2008; 90A: 2-9 Crossref Scopus (142) Google Scholar , 2 Bäthis H. Perlick L. Tingart M. Lüring C. Zurakowski D. Grifka J. Alignment in total knee arthroplasty. A comparison of computer-assisted surgery with the conventional technique. J Bone Joint Surg Br. 2004; 86B: 682-687 Crossref Scopus (487) Google Scholar , 3 Saragaglia D. Picard F. Chaussard C. Montbarbon E. Leitner F. Cinquin P. Computer-assisted knee arthroplasty: comparison with a conventional procedure. Results of 50 cases in a prospective randomized study. Rev Chir Orthop. 2001; 87: 18-28 PubMed Google Scholar , 4 Haaker R.G. Stockheim M. Kamp M. Proff G. Breitenfelder J. Ottersbach A. Computer-assisted navigation increases precision of component placement in total knee arthroplasty. Clin Orthop Relat Res. 2005; 433: 152-159 Crossref PubMed Scopus (299) Google Scholar ] and more reproducible and reliable implant positioning [ 5 Krocker D. Weiss U. Tohtz S. Perka C. A prospective, randomized study of computer-assisted and conventional total knee arthroplasty. Three-dimensional evaluation of implant alignment and rotation. J Bone Joint Surg Am. 2007; 89A: 236-243 Google Scholar , 6 Stöckl B. Nogler M. Rosiek R. Fischer M. Krismer M. Kessler O. Navigation improves accuracy of rotational alignment in total knee arthroplasty. Clin Orthop Relat Res. 2004; 426: 180-186 Crossref PubMed Scopus (250) Google Scholar , 7 Bolognesi M. Hofmann A. Computer navigation versus standard instrumentation for TKA: a single-surgeon experience. Clin Orthop Relat Res. 2005; 440: 162-169 Crossref PubMed Scopus (135) Google Scholar ]. However there is additional useful data that is recorded during the surgical procedure that can be used to develop new ways in performing the replacement. In TKA one of the main goals is to obtain flexion/extension gap equivalence where the geometry of flexion and extension gaps are homothetic. The gaps are created by the bone cuts and any soft-tissue releases that are performed, with the sectioning occurring in a structured order. Both mechanical devices and navigation with a computer can be used as aids in achieving gap equivalence. It is essential to have an instrumentation system that can be used for conventional as well as for computer assisted surgery so the surgeon can choose either, and also as a back-up if there are technical problems with the computer system. This allows changing to a conventional TKA without having to change the instrumentation.