Introduction: The most critical step in the ACL reconstruction is placement of the femoral and tibial tunnels into which the graft is secured. The purpose of this prospective randomised study was to assess biomechanical, radiographic and functional results after single-bundle anterior cruciate ligament (ACL) reconstruction using navigation system.

Materials and Methods: 80 patients were treated for chronic rupture of the ACL. They were involved in a prospective randomized double-blinded study. All patients gave informed consent. 40 patients underwent ACL reconstruction using OrthoPilot navigation system (Group 1) and in other 40 patients was the surgery done by standard manually targeting technique (Group 2). The anterior laxity was measured using a KT-1000 arthrometer. Femoral and tibial tunnel position was evaluated radiologically according to the method described by Bernard/Hertel and Harner, respectively. The questionnaire-based Lysholm scale was included to compare functional state in both groups. The follow-up was at least 2 years.

Results: The knees in Group 1 were as stable as those in Group 2 during the arthrometer testing with lower value of dispersion. The postoperative Lysholm score had the same value in both groups. Statistical differences exist between anterior-posterior femoral tunnel placement when comparing the navigated and standard technique; in Group 1 were found out more exact results. No significant complications were observed.

Conclusions: Used computer kinematic system improves accuracy of the antero-posterior femoral tunnel placement. It also decreases dispersion of biomechanical stability values. This device renders the procedure more reliable and may so reduce the rate of revision surgery.