[Computer-assisted open-wedge osteotomy]

Abstract

Aim: The open-wedge high tibial osteotomy is an established procedure for the treatment of the unicompartimental gonarthrosis in young patients. An adequate correction of osseous malalignment is crucial for a sufficient reduction of stress in a diseased compartment. We have examined reliability and precision of an intraoperatively used computer-assisted navigation system for high tibial osteotomy. The aim of the study is to show the equivalent safety and effectiveness of high tibial osteotomies carried out with the computer-assisted navigation system. It is assumed that a good correlation between the mechanical tibio-femoral axis as measured by radiography and by the navigation system can be achieved.

Method: 40 medial open-wedge osteotomies were performed with computer-assisted navigation on 39 patients (27 males, 12 females) between 1/2004 and 8/2006. The average age was 46.3 years (range: 26 - 64 years), the average weight was 83.2 kg (range: 54 - 118 kg).

Results: A good correlation between radiographic data and the data acquired with the navigation system was found for the tibio-femoral axis: preoperative data (8.0 +/- 2.5 degrees, radiographic; 7.8 +/- 2.1 degrees navigated) for varus alignment. The postoperative correlation was lower than the preoperative one (postoperative data (0.6 +/- 3.2 degrees radiographic; - 0.7 +/- 1.0 degrees navigated) for valgus alignment. In 2 patients a loss of correction occurred and had to be treated operatively.

Conclusion: High tibial osteotomy is an established therapy procedure for unicompartmental gonarthrosis. It can be improved in its precision and reliability by computer-assisted navigation.