CONVENTIONAL TOTAL KNEE ARTHROPLASTY AND COMPUTER-ASSISTED NAVIGATION: COMPARATIVE SHORT-TERM ANALYSIS OF TWO MATCHED SERIES (156 IMPLANTS)

Abstract

Purpose: Classical instrument sets for implantation of total knee arthroplasty (TKA) can be perfected. Computer-assisted implantation appears to offer improved technical quality. The purpose of this study was to compare a matched series of TKA implanted with the conventional method and with a computer-assisted navigation system.

Material and methods: Seventy-eight prostheses implanted with a computer-assisted system based on 3D CT-scan reconstruction of the lower limb were matched with 78 prostheses implanted by a highly-trained operator. The knees were matched for gender, aetiology, surgical approach, and axial deviation. There were no significant differences between the groups for these variables. An intramedullary aiming device was used for knees undergoing the conventional procedure. Navitrack(r) was used for the computer-assisted implantations. The same prosthetic system (Wallaby) was used for both series. An independent operator assessed the double-foot stance gonometries. The femorotibial axis was measured as was the individual position of the tibial and femoral pieces.

Results: Axis was within 3° varus and 3° valgus for 92% of the knees operated on with the navigation system. This same range was found for 59% of the conventional procedures. The difference was significant (p< 0.0001). Analysis of the individual femoral and tibial components did not demonstrate any significant difference.

Discussion: Results of TKA are dependent in part on operative technique. The objective is generally achieved with the computer-assisted technique but is not with the conventional technique. Navigation could be useful to achieve successfully short-term objectives. Its contribution to mid-term outcome remains to be demonstrated.