Hello, I am Amanda one I'm from Penn State Health and Penn State College of Medicine and I'll be talking to you about men bone loss and prior hardware in revision ACL reconstruction. These are my disclosures, none of which are relevant to this talk revision ACL reconstruction occurs more often than I think we would like to admit in up to 11% of patients in total and in particular in the younger active running cutting running cutting evening athletes. This number can increase up to 30%. When doing ACL revision reconstruction it's common to have tunnel malposition tunnel dilation bone loss and bone resorption as well as retain hardware. And these will need to be dealt with during your revision case. The discussion of revision ACL reconstruction would be remiss without a discussion on determining for the need to determine the cause of the index surgery failure. It can be due to a number of different ideologies including Miss pathology meniscus and or postural out of corner, and or alignment, but 60% of ACL reconstructions will fail due to a technical error and the most common technical error is incorrect position, incorrect tunnel position can lead to tunnel widening due to improper graph placement, it can be a mechanical ideology and windshield wipering phenomena. It can be due to graph type or bioabsorbable materials used in fixation, or even just synovial fluid propagation if graph sizing was not appropriate. And always, as we need to be concerned about infection should be worked out and evaluated for. So one of the first decisions you'll need to make when doing a revision ACL reconstruction is whether you're going to do this single versus two stage, a two stage revision occurs less commonly but you'll need to consider this in cases of significant challenges, such as tunnel widening, greater than 15 millimeters, significant loss of range of motion especially extension, which should be reconciled prior to doing your definitive surgical reconstruction active infection as I discussed earlier needs to be worked up including blood work, and possibly aspiration. And if indeed the patient has an active infection that'll want to be reconciled prior to doing your definitive revision reconstruction. And then you can come in surgery that may compromise your ACL reconstruction be at your rehab and or tunnel placement, you may want to do in a two stage fashion, such as osteotomies. If you're really just not sure best to do a two stage revision again you want this to be the last ACL reconstruction that this patient. Here's an example of a two stage revision reconstruction. We have a previous femoral tunnel here that is proximal and posterior. And so we're going to spend some time, removing the previous bone graft as well as tunnel material or previous fixation material from this tunnel. And then we'll graph this with a combination of cannulated bone dowels made by a variety of allograft companies, as well as croutons, and then we can impact that with a bone tamp and or our cannulated dilator help compress that bone and really give us a nice press fit for incorporation. Here on the tibial tunnel, if we put the scope up the tunnel we see a number of different material types including suture, previous graft, bioabsorbable fixation material, you want to get all that out, spend some time with your curette, air ranger, and constantly putting the scope back up into that tunnel and make sure all that's removed and then I will re-ream this so I can really get fresh bleeding bone circumferentially around my tunnel, and even use a wire, guide wire to help help trephinate the walls, again to help with incorporation of your bone graft and then ultimately again I'll use a combination of allograft bone dowels as well as croutons to really impact and fill that previous void. And then in the end, to help with synovial fluid, to help prevent synovial fluid propagation, I'll use fibrin glue to help seal the tunnel apertures on both the femoral and tibial side, again to help with that integration. I'll get a CT scan at four months to determine the bone graft tunnel healing, and if appropriate, I'll go ahead and proceed with my second stage of my revision. A single stage revision is done more commonly, this is done in cases of good bone stock or with less than 15 millimeters of tunnel diameter after necessary removal of previous hardware and re-reaming of your tunnel. Remember when you re-ream, you're going to lose approximately another millimeter or two of bone there, so you have to factor that in to your calculations when determining single versus two stage. If your tunnels are grossly malpositioned, this may be the best case scenario, but you can potentially avoid them completely. Consider keeping your previous hardware or interference screws to prevent wall collapse and then drilling your new tunnel. If they're slightly malpositioned, which tends to be much more common, you'll need a strategy to reconcile these quote unquote snowman tunnels. Some of these strategies may include a funnel technique where you'll have coalescing tunnel apertures at the articular margin inter-articulately and then divergent proximally and distally. You can use stack screws or even matchstick autograft or allograft shims. Also, both have been found to be biomechanically sound for providing good fixation on your revision. My favorite technique is the use of dilators. I like to do a funnel technique where essentially I'll have converging tunnels at the aperture or at the articular margin and diverging distally. I'll drill small, usually a five millimeter, and then I'll dilate up to the diameter ultimately that I have sized my new graft to. Essentially, as I'm dilating up, I'm autografting the previous tunnel using bone from the patient to essentially fill that in as I'm pushing that bone into that other previously malpositioned tunnel. I think with doing a single stage revision, you really need to be very well prepared here and have a number of different techniques, and especially techniques to find where you're going to put your tunnel. Remember your anatomy and your typical bony and your osseous and soft tissue landmarks will be distorted, and so you need to have some reliable strategy to find where these tunnels should be. Some ways of doing it that I like to use include for my femoral tunnel using a ruler. You can take approximately the 50% mark from anterior to posterior using that ruler, and that's been shown to correlate well with 3D CT imaging and anatomic placement of the tunnels. A Bernard and Hurdle grid also is an excellent way to do it using lateral fluoroscopy, and you want to place your all or your start point for your tunnel at approximately 26% of the depth of the LFC and 34% of the height for your tibial tunnel. For the tibial tunnel, you can simply use a Stabile enrotioning technique, and once you get a good lateral of the lateral tibial plateau, you can place this tunnel approximately 40% of the distance from anterior to posterior, and that correlates well with the anatomic location of the tibial attachment. You need to have an armamentarium of drilling techniques, including outside-in, inside-out, flexible reamers, as well as a variety of different fixation techniques, including buttons and posts if needed, because again, you're not sure what the quality of bone will always be, and you want to make sure you leave that patient confident that you've given them the best and most secure fixation you can provide them. Here's an example of a single-stage revision. Again, our tunnel, our femoral tunnel is proximal and posterior. I'm using a ruler technique and placing my femoral aperture approximately 50%. You can use a Bernard or Hurdle grid. Again, have a variety of drilling options. This is a flexible reamer system. Again, I'm going to drill small and then dilate my new tunnel, bone grafting, essentially autografting that previous femoral tunnel, and making sure that I get an appropriate bony bridge between my new tunnel and the previously malpositioned tunnel. On my tibial side, my tunnel in this case is posterior, and so I want to drill my new tunnel anterior to this or my aperture to end coalesce anterior. Again, this will be a divergent tunnel technique or funnel technique. I'm going to drill small at approximately five millimeters and then dilate up, and so thereby autografting my previously malpositioned tunnel using the patient's own bone to fill that in. Placing the scope up, my newly formed dilated tunnel will ensure that I have adequate bone 360 degrees circumferentially around this, as well as good bleeding milieu for a bone or for a graft incorporation. Finally, when possible, you'd like to use autograft in revision settings. If the patellar tendon is available, that's an excellent graft and allows you to also titrate how much bone that you may take to fill in any potential previous bone voids. In conclusion, you want to determine your single or two-stage reconstruction based on the previous tunnel location, whether these anatomic or non-anatomic, whether there's a dilation and how much dilation, whether you need to reconcile previous procedures or perform additional procedures, whether you need to reconcile range of motion challenges and or active infection. You need to have an armatarium of techniques and instruments to include outside-in, inside-out, as well as trans-tibial drilling options in any case of a revision and especially in single-stage revision situations. You want to have bone dowels, tunnel dilators, and multiple, multiple methods of fixation, including aperture as well as suspensory and posts and buttons. These all may be used depending upon bone quality in the revision situation. When possible, using metal interference screws and autograft have been shown to improve outcomes in revision ACL reconstructions. Your anatomy will be distorted. You need to have a strategy as far as how you're going to find your apertures anatomically. And I would suggest using a combination of fluoroscopy, as well as Osseous landmarks, as well as a ruler, all of which can be very helpful for determining your new ACL revision reconstruction tunnels. Thank you.

ACL revision surgery

tunnel malposition

bone loss

fixation methods

autograft