[Early clinical outcome after navigated total knee arthroplasty. Comparison with conventional implantation in TKA: a controlled and prospective analysis].

BACKGROUND

Navigated implantation of total knee prostheses has become more and more popular within the last decade in orthopaedic surgery. Although improved alignment after navigated knee surgery has been reported previously in the literature, only a few studies meet the criteria of a level-1 evidence-based medicine study. We present the results of a controlled and prospective study comparing early clinical outcomes after computer-assisted versus conventional implantation in total knee arthroplasty (TKA).

METHODS

Within a 15-month period, all patients admitted for primary TKA were followed prospectively. Each patient was evaluated using the Knee Society Score (KSS) preoperatively, 10 days after surgery, and 3 months after surgery. The patients were divided into two groups, and the implantation technique altered between the two treatment options: each conventional implantation was strictly followed by a computer-assisted procedure and vice versa.

RESULTS

From March 2003 to June 2004, we did 34 computer-assisted (group A) and 35 conventional knee arthroplasties (group B) in 62 patients. There was no difference in the preoperative status of the patients. Surgeries in group A took significantly longer than in group B. The average deviation from correct alignment was significantly reduced in group A. 66 of 69 of the TKAs were available for follow-up examinations after 10 days and after 3 months. No significant differences were found in the overall KSS scores or in the subgroups.

CONCLUSIONS

The intraoperative use of a computer-assisted navigation system during implantation of a total knee prosthesis reduced the average varus/valgus deviation from the anatomical long leg axis. A disadvantage of the computer-assisted surgical procedure may be the longer operating time. Long-term follow-up of the presented data is needed in order to show whether the improved average alignment is advantageous for patients and/or results in a longer service life of the TKA.