[Computer-assisted open-wedge osteotomy].

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.