Reconstruction du ligament croisé antérieur : Détermination du “meilleur” point isométrique fémoral assistée par ordinateur

Current concept in rotational laxity control and evaluation in ACL reconstruction

Rotation combined with translation; compose the three-dimensional motion of the knee subluxation in anterior cruciate ligament deficient knee. The worldwide scientists were focused initially on the translation part of this complex 3D motion, but since the beginning of the century there was a large interest on knee rotational laxity study. Lot of paper reported new devices and results with an explosion since the beginning of the decade. The purpose of this review is to provide an extensive critical analysis of the literature and clarify the knowledge on this topic. We will start with a dismemberment of different rotational laxities reported: the rotation coupled with translation in 2D tests such as Lachman test and anterior drawer test; the rotational envelope considering the maximum internal external rotation; and the "active rotation" occurring in 3D Pivot-shift (PS) test. Then we will analyze the knee kinematics and the role of different anterior cruciate ligament (ACL) bundle on rotation. A review of different mechanical and radiological devices used to assess the different rotations on ACL deficient knees will be presented. Two groups will be analyzed, dynamic and static conditions of tests. Navigation will be described precisely; it was the starter of this recent interest in rotation studies. Opto electronic and electromagnetic navigation systems will be presented and analyzed. We will conclude with the last generation of rotational laxity assessment devices, using accelerometers, which are very promising.

Computer assisted reconstruction of the anterior cruciate ligament

Reconstruction of the anterior cruciate ligament is a delicate task for which many different techniques have been proposed. A system consisting of a computer and a three-dimensional optical sensor is proposed to help the surgeon control the placement of a graft. This system can be used to minimize anisometry of the graft and avoid notch impingement. The same system, which had been validated by previous testing on 20 fresh human anatomic specimen knees, was tested on 23 patients who had an anterior cruciate ligament injury. Tunnel placement was performed using the standard technique of Morgan et al and was measured with the computer based system. It was found that all cases had different configurations of tibial and femoral placement. The computer based anisometry measurements ranged from 1.9 mm to 8.8 mm in the anterior part of the graft, and from 1 mm to 13 mm in the centers of the tunnels. Using the computer retrospectively, it was possible to find configurations of the graft in all cases that avoid notch impingement, with anisometry values ranging from 1.3 mm to 3.7 mm. This study shows that a computer based system can be a useful tool for routine anterior cruciate ligament reconstruction and can be useful for research purposes.