Comparative study of knee anterior cruciate ligament reconstruction with or without fluoroscopic assistance: a prospective study of 73 cases. Anterior cruciate ligament reconstruction using navigation: a comparative study on 60 patients. Differences in the placement of the tibial tunnel during reconstruction of the anterior cruciate ligament with and without computer-assisted navigation. Outcomes after conventional versus computer-navigated anterior cruciate ligament reconstruction.
Correct placement of both tibial and femoral tunnels is one of the main factors for a favorable clinical outcome after anterior cruciate ligament (ACL) reconstruction. We used an original system of computer assisted surgery (CAS). The system, based on fluoroscopic guidance combined with special graphical software of image analyzing, showed to the surgeon, before drilling, the recommended placement of tibial and femoral tunnel centers. We compared the first anatomical and clinical results of this procedure to the usual one single incision technique.
                We conducted a prospective study on 73 patients; 37 patients were operated on with CAS and 36 without CAS, by the same senior surgeon. The mean age was 27 years for both groups. Every patient was reviewed at an average of 2.2 years (range 1-4.5) by an independent observer, using IKDC scoring system, KT-1000, and passive stress radiographs.
                Time between ACL rupture and reconstruction averaged 30 months for both groups. CAS needed 9.3 min extra surgery time. Clinical evaluation was graded from A to C as per the IKDC scoring system: 67.6% A, 29.7% B, 2.7% C with CAS; and 60% A, 37.1% B, 2.9% C without CAS. IKDC subjective knee evaluation score averaged 89.7 with CAS and 89.5 without CAS. Pre operative KT-1000 maxi manual differential laxity averaged 7. At revision time, all the patients after CAS had a differential laxity less than 2 and 97.7% without CAS. Stress X-rays differential laxity averaged 2.4 mm with CAS and 3 mm without CAS. The area of dispersion of the tunnels' center was smaller on the femoral side using the CAS method. There was no statistically significant difference between both groups using IKDC score, KT-1000 and passive stress radiographs.
                The CAS method provided a more accurate and reproducible tunnels placement without clinical significant effect. Poor outcome in anterior cruciate ligament reconstruction is often related to tunnel position.
                Improving accuracy of the tunnel position will lead to improved outcome.
                Randomized controlled trial; Level of evidence, 1.
                Sixty patients were randomized to either standard instrumentation or computer-assisted guides to position the tibial and femoral tunnels. The results were evaluated on clinical outcome based on International Knee Documentation Committee form (laxity) and radiologic assessment: radiologic Lachman (Telos at 150 and 200 N) and analysis of the tunnel positions.
                International Knee Documentation Committee laxity was level A in 22 knees in the conventional group (mean, 1.5 mm at 200 N) compared with 26 navigated knees (mean laxity, 1.3 mm; P = .49). Laxity was less than 2 mm in 96.7% of the navigated group and 83% of the conventional group (P = .292). The variability of laxity in the navigated group was significantly less than in the conventional group, with the standard deviation of the navigated group being smaller than that in the conventional group (P = .0003 at 150 N and .0005 at 200 N Telos). A significant difference (P = .03) was found between the groups in the ATB value (distance between the projection of the Blumensaat line on the tibial plateau and the anterior edge of the tibial tunnel), characterizing the sagittal position of the tibial tunnel (negative ATB values imply graft impingement in extension). In the conventional group, mean ATB was -0.2 (-5 to +4), whereas it was 0.4 (0 to 3) in the navigated patients. There were no negative ATB values in the navigated group.
                This study confirms that the accuracy and consistency of tibial tunnel position can be improved by the use of computer-assisted navigation and that the clinical result in terms of laxity is more reliable. Next to graft fixation, correct positioning of the tibial and femoral tunnel is a deciding factor for the clinical result of anterior cruciate ligament reconstruction surgery. Computer-assisted navigation has been proposed as a method to improve tunnel positioning.
                To examine the differences in tibial tunnel placement between cruciate ligament operations using manual and computer-assisted navigation.
                Randomized controlled trial; Level of evidence, 1.
                Between December 2003 and April 2004, 53 athletes underwent anterior cruciate ligament reconstruction surgery with arthroscopic press-fit technique. The first group (group N; 24 athletes) were operated on with the aid of a navigation system (OrthoPilot, Aesculap AG & Co. KG, Braun), and the second group (group M; 29 athletes) were "manually" operated on. A lateral radiograph of the knee at maximum extension was used to determine the exact position of the tibial tunnel four days postoperatively. In the measurements, the anterior and posterior boundaries of the tibial tunnel, as well as the center of the tibial tunnel in relation to the maximum tibia anteroposterior diameter were evaluated (indicated in percent). An analysis of the tibial tunnel position proportional to the slope of the intercondylar roof was done to determine intercondylar impingement (method according to Howell). The centers of the tibial tunnels were compared with the "optimal" position noted in previous studies. The standard deviation was determined for both groups to determine the variance of placement.
                The anterior tibial tunnel border was 19.4 mm in group M (29.7%) and 21.2 mm in group N (32.2%) (P = .18). The center of the tibial tunnel was located at 24.6 mm in group M (35.6%) and at 26.6 mm in group N (40.3%) (P = .19). In group M, the posterior tibial tunnel position was located at 30.2 mm (46.2%), and in group N at 32.2 mm (49.1%) (P = .21). When comparing the centers of the tibial tunnels with the optimal 44% found in previous studies, the value for group M (37.6%) varied significantly, while group N (40.5%) did not. However, there was no significant difference in the range variance for either group; the standard deviation was 6.9% (4.3 mm) for group M and 5.9% (3.5 mm) for group N. One athlete showed moderate impingement in group N, and two athletes in group M.
                Assisted navigation offers good support for correct placement of the tibial tunnel, although experienced surgeons can achieve essentially the same positioning as surgeons using computer-assisted navigation. Whether it is advisable to implement this procedure in daily surgical routine should be decided based on clinical results. The purpose of this prospective randomized study was to assess biomechanical, radiographic, and functional results after single-bundle anterior cruciate ligament (ACL) reconstruction by use of a navigation system.
                ACL reconstruction was performed by use of the OrthoPilot navigation system (B. Braun-Aesculap, Tuttlingen, Germany) in 40 patients (group 1); and in another 40 patients, surgery was done by the standard manual targeting technique (group 2). The anterior laxity was measured with a KT-1000 arthrometer (MEDmetric, San Diego, CA). Femoral and tibial tunnel position was evaluated radiologically according to the method described by Bernard and Hertel and by Harner et al., respectively. The questionnaire-based Lysholm and International Knee Documentation Committee scales were included to compare the functional state in both groups.
                The knees in group 1 were as stable as those in group 2 during the arthrometer testing, with a lower value of dispersion. The postoperative Lysholm and International Knee Documentation Committee scores had the same value in both groups. Statistical differences existed with regard to anterior-posterior femoral tunnel placement when the navigated and standard techniques were compared; in the navigated group, more exact results were found. No significant complications were observed.
                The only difference that we found between the navigated and standard groups was in radiographic tunnel position measurement. The computer-assisted navigation technique in our study resulted in more accurate tunnel placement in the femur (but not the tibia) than the traditional arthroscopic technique. However, the performed standard radiographic measurements are of limited precision in principle. Functional scales and stability tests gave similar results in both groups.
                Level I, therapeutic study.
A favourable effect of computer assisted surgery for cruciate ligament reconstructions of the knee compared with conventional reconstructions could neither be demonstrated nor refuted. There is insufficient evidence to advise for or against the use of CAS. There is a need for improved reporting of future studies of this technology.