AVOIDING TUNNEL CONVERGENCE IN LATERAL FEMORAL CONDYLE DURING SIMULTANEOUS ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION AND POSTEROLATERAL CORNER RECONSTRUCTION: A REVIEW ARTICLE

Background- The tunnels for PLCR and ACLR occupy the lateral femoral condyle where collision is expected to occur during simultaneous reconstructions. A review of available studies was undertaken to find the safe arc while drilling PLC tunnels. 5 similar studies that Methodologyused CT scan-based evaluation of tunnels in cadaveric/ synthetic/ 3D developed knee models were included. Anteromedial (AM) portal with centre of anatomic ACL remnant as entry was used for ACL tunnel in all studies. Tunnel orientation in form of coordinates is presented as (coronal plane angle, axial plane angle) The convergence for FCL tunnel in complete neutral position (0,0) was repo Results- rted to be as high as 100% in 2/5 studies and 86% in one. Safety arc for FCL tunnel ranges from 0-20⁰ proximally and 20-40⁰ in anterior direction with 3/5 studies reporting 0% convergence while 5% risk was reported in one study with 30⁰ anterior directed tunnel. 2/5 studies involved PLT tunnels, for which the recommended orientation is that of 0⁰ or 30⁰ proximally and 30⁰-35⁰ directed anteriorly with 0 tunnel convergence. (0,0) orientation of ConclusionFCL tunnel is always to be avoided. The recommended FCL tunnel orientation to minimise tunnel convergence risk is (0⁰,30⁰-40⁰) which also leaves a safe inter-tunnel distance of an average of 4.4 mm if tunnels don't converge. Similar recommendation for PLT tunnel is (0⁰, 30⁰-35⁰) which primarily avoids the breach of intercondylar notch. For a small LFC (<35mm), FCL tunnel drilling in recommended (0⁰,20⁰-40⁰) is even more important to avoid convergence.