Mota e Albuquerque RF, Sasaki SU, Amatuzzi MM, Angelini, FJ. Anterior cruciate ligament reconstruction with double bundle versus single bundle: experimental study. Clinics. 2007;62(3):335-44. OBJECTIVE:To test an intra-articular reconstruction of the anterior cruciate ligament of the knee in 10 human cadavers by replacing 2 anterior cruciate ligament bundles, with the purpose of producing a surrogate that would be structurally more similar to the anatomy of the anterior cruciate ligament and would provide the knee with more stability. METHODS: We reconstructed the anteromedial and posterolateral bundles using a quadriceps muscle tendon graft that included a patellar bone segment. The anteromedial bundle was replaced in 10 knees (5 right and 5 left knees from different cadavers) by a quadriceps-bone tendon graft, and the anteromedial and posterolateral bundles were replaced in the matching pairs of these knees. In the latter, the bone segment was fixed to the tibia, and the tendinous portion of the graft was divided longitudinally creating two 5-mm wide bundles that were inserted individually into the femur through 2 independent bone tunnels. Then, the knees were tested mechanically to evaluate the tibial anterior dislocation in relation to the femur, as well as the rigidity of the graft. The control group was formed by the knees with intact anterior cruciate ligaments, before being resected to be reconstructed. RESULTS:The results obtained did not show superiority of double-bundle reconstruction over single-bundle reconstruction, and neither technique provided the knee with the same stability and rigidity of the intact anterior cruciate ligament. CONCLUSION: Our hypothesis, based on the anatomy and biomechanics of the knee, that reconstruction of the anterior cruciate ligament using 2 bundles would result in a more anatomic reconstruction and provide better containment of the anterior tibial translation was not supported by the results of this study.

OBJECTIVES:To compare the accuracy of tunnel placement and graft isometry for anterior cruciate ligament reconstruction performed using a computer-assisted navigation system (Orthopilot) and using traditional instruments.METHODS:The anterior cruciate ligament was removed intact from 36 pairs of human cadaver knees. From each pair, one knee was randomized to Group 1 (conventional) and the other to Group 2 (Orthopilot). An inelastic suture was then passed through the central points of the tibial and femoral tunnels. Neither of the tunnels was drilled. All knees were then dissected, and six parameters were obtained: distances from the tibial tunnel center to the 1) posterior cruciate ligament, 2) anterior horn of the lateral meniscus and 3) medial tibial spine; 4) distance from the femoral tunnel center to the posterior femoral cortex; 5) femoral tunnel coronal angle; and 6) variation of the distance from the femoral to the tibial tunnel with the knee extended and at 90 degrees of flexion.RESULTS:The variation of the distance from the femoral to the tibial tunnel during flexion and extension was smaller in the Orthopilot group (better isometry) compared to the conventional group. There were no statistical differences in any other parameters between the groups, and all tunnels were considered to be in satisfactory positions.DISCUSSION:The results obtained for anterior cruciate ligament reconstruction depend on precise isometric point positioning, and a navigation system is a precision tool that can assist surgeons in tunnel positioning.CONCLUSION:No differences in tunnel position were observed between the groups. Nonetheless, better isometry was achieved in the Orthopilot group than with conventional instruments.

The purpose of this study was to assess the flexor-extensor group of muscles of the knee in young athletes diagnosed with a total rupture of the anterior cruciate ligament (ACL). Eighteen knees of 18 athletes (14 men and 4 women) with an average age of 21.6 years (range 16-32 years) were assessed with a Cybex 6000 model isokinetic apparatus. The average internal between occurrence of the injury and assessment was 10.2 months (range 2-48 months). There was an associated meniscal injury in eight of the knees. Athletes with any other kind of associated injury, limitation, or blockage of the movement of the joint, significant pain during the exam, or interval between injury and exam of less than two months were excluded from the study. The parameters studied were the peak torque-velocity and flexor-extensor relationships at the constant angular velocities of 60 degrees/sec and 240 degrees/sec. Previous warming-up was done by means of an ergometric bicycle and adaptation with 3 submaximal repetitions. The contra-lateral side, which presented no injury, was used as control. Peak torque (PT) at the constant velocity of 60 degrees/sec was greater than that at 240 degrees/sec for knees with and without injuries. However, there was no significant difference between the injured and uninjured sides at 60 degrees/sec or at 240 degrees/sec. The average value for the flexor-extensor relationship at 60 degrees/sec on the injured was 60% ((6), compared to 57% ((10) on the contra-lateral side. At 240 degrees/sec, the average value was 75% ((10) on the injured side, and 65% ((12) on the contra-lateral side. In conclusion, despite the complete rupture of the ACL of one knee, the average values for the flexor-extensor relationship were similar on the injured and uninjured sides at the velocity of 60 degrees/sec. As the velocity increased, an increase in the values for the flexor-extensor relationship of the knee also occurred, indicating a tendency of the performance of the flexor muscle group to approach that of the extensor muscle group, and this tendency was more pronounced on the side of the injury.