Why navigation o the ACL is important

摘要

"The question is how to find the best placement in the individual knee considering the large variations among individuals". J. Gilquist [2]. Background and Objectives: A rupture of the Anterior Cruciate Ligament must benefit from reconstruction with a graft that is positioned 1) anatomically 2) isometrically and 3) with no notch impingement. Respecting those criteria depends on a correct positioning of tunnels. A good positioning of the femoral tunnel is critical for the isometry and for preventing notch impingement. Theory is often more simple than practice and even for a surgeon having a good knowledge of the ACL, those objectives are difficult to meet for each patient. To face this challenge, the Grenoble group has conducted research studies on ACL reconstruction image-free computer assisted surgery since 1992 with the objective to design a comprehensive, accurate, easy and fast solution. The result of more than 10 years of work is now implemented as an efficient Computer Assisted Surgical Protocol (CASP) on the Surgetics navigation platform (Praxim, France): ACL Logics. Design and Methods: Since the early work in 1992, we designed a method that does not use CT, MR or fluoroscopy to make it convenient in clinical routine. The initial system was based on the reconstruction of spline patch surfaces to get an initial 3D representation of the tibial plateau and the femoral notch, but the result was not intuitive. Therefore we designed a method using Bone Morphing technology based on deformable statistical models [1] in order to obtain 1) detailed surfaces in the critical areas (potential regions of insertion on femur and tibia, arch of the femoral notch for accurate computations with 0.5mm mean errors and 2) global representations of femur and tibia for intuitive use in clinical routine.