The Use of the 70° Arthroscope for Anatomic Femoral and Tibial Tunnel Placement and Tunnel Viewing in Anterior Cruciate Ligament Reconstruction

Abstract

The use of the 70 arthroscope in knee surgery is not a new concept, and it is frequently used in posterior cruciate ligament reconstruction. There are previous reports of its use in anterior cruciate ligament surgery, but it has not achieved routine use. With the move toward anatomic anterior cruciate ligament reconstruction, it is recognized that accurate tunnel placement is vital for a good clinical outcome. Visualization of the femoral and tibial footprints can be variable with the use of only an anterolateral viewing portal, and it may be necessary to create accessory anteromedial portals, which can cause problems with instrument crowding. Overall, the 70 arthroscope provides an excellent view of the femoral and tibial footprints and a view of the full length of the femoral and tibial tunnels through a single anterolateral viewing portal.

A comparison of femoral tunnel placement in ACL reconstruction using a 70° arthroscope through the anterolateral portal versus a 30° arthroscope through the anteromedial portal: a pilot 3D-CT study

“…Alternative proposed techniques (to maximise visualisation) include the use a 30°arthroscope via an accessory anteromedial portal [21,22] or central viewing portal [23]. We chose to use the 70°arthroscope as it allows for medial portal drilling without over-crowding or additional portal creation, with most surgeons accustomed to using this arthroscope for posterior cruciate reconstruction [4,5]. Additional benefits have also been described including the improved bird's-eye view of the tibial footprint during tunnel positioning [5].…”

“…Therefore, a goal for the surgeon is to accurately position the tunnels in relation to either anatomical landmarks or direct measurements [2,3]. The femoral tunnel is a particular challenge as, when the medial wall of the lateral femoral condyle is viewed from the anterolateral portal using a 30°arthroscope, a foreshortened perspective is achieved [4]. Therefore, many surgeons switch to viewing via the anteromedial portal to confirm placement (prior to tunnel drilling).…”

“…However, the surgeon then must switch back to the anterolateral portal for drilling or risk over-crowding by viewing through an accessory anteromedial portal. An alternative technique is the use of a 70°a rthroscope through the anterolateral portal [4,5]. This provides a less foreshortened view of the footprint of the ACL that is comparable to the 30°arthroscope view from the anteromedial portal ( Fig.…”

“…1). Perceived advantages of using the 70°arthroscope are that it prevents the need for switching between portals, it can be maintained whilst the tunnel is drilled, and it gives an improved "bird's eye" view of the tibial footprint for tunnel placement [4,5]. Whilst this technique is well described, no previous studies have compared the accuracy of this versus the use of a conventional 30°arthroscope.…”

Anatomic Anterior Cruciate Ligament Reconstruction: The Use of the Anterior Horn of the Lateral Meniscus as a Guide to Tibial Tunnel Placement

“…has published this technique and the advantage the 70 arthroscope provides in viewing the ACL tibial and femoral footprints, as well as giving a full view of the tibial and femoral tunnels when prepared. 8 …”