Axial deviation in total knee arthroplasty--is the navigation system necessary?

BACKGROUND

The aims of the total knee arthroplasty are to reduce or completely relieve pain and improve mobility of the affected joint. In the last decade navigation systems based on computer and infrared camera technology are developing quickly as an alternative to conventional surgical navigation techniques.

METHODS

We compare post-operative results in 2 groups of patients after total knee arthroplasty. The groups consist of patients operated with the navigation system performing total knee arthroplasty compared with another group patients where we implanted the total knee arthroplasty using mechanical navigation system for bone resection. All patients suffered from gonarthrosis grade III or IV and had pre-operative axial deformity of the mechanical axis in the knee more than 10 degrees. Post-operative follow up X-ray was aimed to establish the mechanical axis of the limb (Mikulicz line). Statistical analysis was directed on testing the difference between two groups using the method of Mann-Whitney non-parametric test.

RESULTS

Using the computerised navigation system we achieved excellent or good result in as much as 94% patients; whereas using the conventional navigation such results were in 87%. It was delightful to find that using the computerised navigation system we did not have any dissatisfactory result and the range of axial deformities deviating from the ideal Mikulicz line was significantly reduced.

CONCLUSION

Results of our study show advantage in using the optoelectronic navigation system in total knee arthroplasty. Computerised navigation system enables exact insertion of knee components which results in longer life-span of the prosthesis (Tab. 2, Fig. 6, Ref. 19).