Specialized Toolkit Series: ACL Reconstruction-Drilling the Tibial Tunnel

Drilling the Tibial Tunnel

Video Transcription

Hey there, my name is Dr. Patrick Joyner. I'm here to discuss with you some techniques in drilling the tibial tunnel for ACL reconstruction.  So basically there's two techniques to keep it simple. You have the outside in, some people refer to that as trans-tibial.  That's where we're starting on the outside of the proximal medial tibia and drilling to the inner part of the knee at the ACL footprint on the tibia.  The inside out is where we insert our retrograde drill into the knee at the footprint at the ACL and then we open the drill and drill backwards from the inside out.  This inside out is commonly referred to as retrograde drilling. First we'll start with outside in. There's two different types of reamers.  As you can see on the slide, we have a fluted reamer up on the top part and an acorn reamer at the bottom. They each have their advantages.  Fluted reamers are excellent for making a smooth tunnel and a straight line. So it does make a smoother tunnel.  I would highly recommend the fluted reamer for the tibia if performing a graft with a bone plug such as a BTB or a quadriceps tendon with a patellar bone plug.  If you have to pass a bone plug through the tibial tunnel, the fluted reamer is your friend. Acorn reamers may give you a little more flexibility.  They're great on the femoral tunnel doing an intermedial technique. They allow for modifications in tunnel direction.  However, at the aperture on the cortex of the medial tibia, it's not quite as smooth a tunnel. So if you're using a bone plug, it can be very difficult to get a bone plug or more  difficult to get a bone plug up an acorn reamer tunnel versus a fluted reamer tunnel. This is not an issue with soft tissue grafts.  Then you have the hybrid reaming technique and this sometimes is a good technique if you've passed your pin and it's slightly anterior on the tibial footprint or posterior on the  tibial footprint. What you'll first do is use an acorn reamer and if it's anterior, you're going to gently  raise your hand and that'll push the acorn a little more posterior for the tunnel and if your pin is slightly posterior, you can drop your hand and that'll pull the tunnel  a little bit anterior. The problem is here again, you've slightly modified the trajectory of the tunnel. It is no longer a straight tunnel.  As a result, you need to keep that guide pin in that tunnel and then revisit the tunnel very quickly with a fluted reamer and that'll give you a smooth straight tunnel to pass  your bone plug. If you're using a graft that's a soft tissue, you do not need the fluted reamer. Now inside out, using the retrograde reamer, this is an example right here.  Every industry partner has their version of a retrograde reamer. The technique is you place your guide on the tibial footprint and this technique is most  commonly used for all inside anterior cruciate ligament reconstructions. You'll place your guide on the ACL footprint on the tibia, you'll advance your reamer up  into the tibia, then you will turn the reamer to open up the blade to the appropriate size and then you advance the reamer back a certain distance depending on the distance of your  tunnel. Then you disengage the blade, put it back inside the reamer, then pull the reamer out completely.  Some physicians choose to use this technique to completely drill the tibial tunnel all the way out of the proximal medial cortex.  If you do that, passing the graft can again be difficult because when you're using a retrograde reamer, sometimes there could be cortical remnants at the aperture.  Therefore, if you use a retrograde reamer for the entirety of the tibial tunnel, I would recommend you put a guide pin back up through the tibial tunnel and revisit that tunnel  with a fluted reamer just to smooth out the tunnel. If you're doing an all inside anterior cruciate ligament reconstruction, that is obviously not necessary.  What I will show here is my preferred technique, which is an outside in, but the fundamentals of the surgery apply here.  As you can see on the picture on the left, I have my guide at the footprint of the anterior cruciate ligament.  On the tibia, I like to leave a stump, some for proprioception and some for identification of the native footprint.  As you can see to the right, that is the posterior aspect of the anterior horn of the lateral meniscus. That is where our ACL footprint is located.  On the picture on the right, you can see my guide pin has been advanced and it's entering  the tibia at the level of the posterior aspect of the anterior horn of the lateral meniscus.  If you're doing an outside in, you need to grasp the guide pin with some form of grasper. I prefer a hemostat through the anterior medial portal, as you can see on the left picture.  If this was a retrograde technique, you would just be opening up the blade and pulling the drill retrograde.  And then on the picture on the right, I've already advanced my fluted reamer. You can see the smooth tunnel at the level at the posterior aspect of the anterior horn  of the lateral meniscus. Thank you. Again, my name is Dr. Patrick Joyner. Below is my email. Please feel free to email me with any questions or concerns.

Video Summary

Dr. Patrick Joyner explains two techniques for drilling the tibial tunnel in ACL reconstruction: the outside-in (trans-tibial) and inside-out (retrograde). The outside-in method involves starting from the outside tibia and drilling inward, with fluted reamers recommended for bone plug grafts and acorn reamers for flexibility in tunnel direction. The inside-out method uses a retrograde reamer, placing the guide on the ACL footprint and drilling backward. Hybrid reaming can adjust tunnel trajectory if needed. Dr. Joyner prefers the outside-in technique and emphasizes the importance of smooth tunnel creation for successful graft passage.

Asset Caption

Patrick Wakefield Joyner, M.D., M.S., FAANA

Keywords

ACL reconstruction

tibial tunnel

outside-in technique

inside-out method

Dr. Patrick Joyner