Prof Adrian Wilson presenting at the North American Faculty Meeting in 2014.
TriLink is my innovation for creating a tri-graft or a double bundle on the femur and a single bundle on the tibia. We’ve done some great research at Imperial College, London, with Andrew Amis. Breck Lord completed his PhD in terms of experience in March 2016, and hopes to write it up over the next 6 months. It's a fantastic piece of work and it’s a very exciting way of doing both ACL and PCL reconstruction using just one tendon, but preparing it in such a way that it gives you two bundles on the femur and a common bundle on the tibia.
Prof Adrian Wilson presenting at the North American Faculty Meeting in 2014.
So, I am going to give you an update today on TriLink which is something that I introduced to this meeting last year and I’ve been doing it for just over a year.
So what is TriLink? Well it’s based on the all-inside principles of GraftLink except that this is a V-graft. So we have two bundles for the femur both fixed with RT TightRopes and one bundle for the tibia, and this can be made with a single semitendinosus tendon or it can be made with an allograft . We’ve used peroneus longus for our cases. I’m now using this for ACL and for PCL.
And just with a semitendinosus it gives you are very favourable graft: So you’ve got this lovely 8.5+ tibial socket and on the femoral side we often have a 6 or 5.5 for the AM and PL bundles - which is bigger than the gracilis if you are a traditional double-bundle guy.
It’s actually easier to make this graft than it is to make the GraftLink. So here I am pulling the semitendinosus through the two RT TightRopes and simply suturing the ends together with some 0 FibreWire, and then taking the graft and placing a third ACL TightRope and folding it in two, and then you can fine-tune the length of the grafts. You make the AM very slightly longer than the PL for the ACL -and mark that - and then we suture it in the standard way and this really is very easy to make.
So what is the evidence for the use of TriGrafts? Well, many of you in the audience will be familiar and happy with using a TriGraft for the PCL and this has been described by many authors.
Also for the ACL there are many descriptions in the literature; this is a nice paper from Zaffagnini from the KSSTA from 2012 and there are some good Japanese papers using TriGrafts for the ACL.
And there are numerous studies out there telling us that double-bundle does beat single-bundle in terms of kinematic studies that have been done.
To my knowledge, Rob LaPrade is the only one that’s compared all-inside single- and double-bundle - and in this study that he presented he showed significant improvement with double- vs single-bundle.
So we have a good rationale for using these TriGrafts. The ACL itself as we all know is not isometric and we can make use of that and we can create the grafts such that we are making the best of the AM and the PL bundles. We can improve footprint fill and this is much more straightforward to do than a traditional double-bundle procedure, and overall it reduces the operative morbidity.
So what about isometry? Well we know that the AM bundle is more tight in flexion, the PL more tight in extension and what we also know is changing position in the centre of the knee on the tibia has very little effect on the isometry of the ACL but you get a huge effect when you move the graft from the deep to the shallow position in the notch.
We also know that with our single-bundle we get at best 60% footprint fill and when we use a double-bundle technique we can improve this to 80 or 90% - this has been published. And when you do these grafts you really get a very favourable appearance when you look in the knee, it really looks like the native ACL and you really fill that footprint
.In terms of tensioning, the only way you can really tension is with the TightRopes - if you want to do differential tensioning of a TriGraft it’s very easy to do. You put the leg into extension, you tighten both the AM and PL bundles and then you fine-tune the AM bundle by taking the knee into certain degrees of flexion until you are happy that you’ve got the correct tension – usually it’s approximately 30 degrees – and like you’ve already heard from Jim, I use a passport cannula.
We’ve tested the TriLink and it has very favourable biomechanical strength in terms of yield and ultimate load.
And we’ve also now started a biomechanical experiment with Andrew Amis at Imperial, and we are using this very sophisticated Staubli robot to apply a certain load and then measure drawer and internal and external rotation at different levels of flexion and what we’re also going to do, like Rob LaPrade has done, is apply a simulated pivot shift and look at GraftLink vs TriLink and look at single-bundle vs double-bundle vs this new tri-construct.
If you want to read about the TriLink procedure we have it as a video on the Arthrex website and also in Jim’s journal Arthroscopic Techniques; he very kindly published our paper on this earlier in the year or last year.
So it’s very simple to do, we just use smaller FlipCutters and we pick those to the size of the grafts, usually you just need to use two FlipCutters, maybe at times I have had to use three, and this is just done in the same way as it is for GraftLink and it’s very easy to do this without having tunnel conversions and issues. There’s the second socket being made.
Initially we were pulling in on the tibia first and then on the femur second, actually I think it is easier to do the reverse of that and to pull in on the femur first but both work. This is the TriLink going in. So, we’re first deploying; we’ve marked out how far we want to go into the tibia and we’ve made markings for our femoral sockets. And of course it’s a learning curve which we’ve now got off of and we can do this comfortably in an hour now - really a very straightforward procedure.
And it’s that TightRope that allows you to get this differential tensioning that makes this really a very straightforward procedure.
So, femoral socket: We use the measuring tools that Jim’s already mentioned, so we use the CaliBlator to mark out exactly where we want to go and we can take a measurement and use the recent descriptions in the literature of where to actually place these bundles, and you can make nice marks before you commit with the FlipCutter and be happy that you are in the right place.
And as I’ve said, and as you’ve heard already from the previous speakers, the FlipCutter is extremely accurate and it’s very easy to make these sockets without actually having issues with tunnel conversions which, having had experience of double-bundle in the past has not been the case for me with more traditional techniques.
Tibial socket is exactly the same as you’ve heard from Jim and we make that in the standard way for the ACL.
Now for the PCL, we’ve just heard a fantastic lecture on this from Dr Stewart and I really think it comes into its own. And I think all-inside makes PCL reconstruction, which I think is a difficult operation, much more straightforward. And of course TriLink really lends itself to this.
So we’ve presented our technique for all-inside PCL reconstruction and again it is there for you to look at on the website and in Arthroscopic Techniques.
And I used the CaliBlator to really push the capsule away as I am going down; it’s perfectly shaped to push away from the neuro-vascular bundle so you can actually use it as a tool for actually pushing the capsule away.
I think the guide is then very easy to place and this is looking from the posteromedial portal, and this is completely safe so you have no issues and no concerns when you drill up and you hit your target there is no chance that you can damage the neurovascular bundle.
In terms of making the graft; this is a peroneus longus which we’ve made into a TriLink, we did our first case a few weeks ago and this was a fantastic graft, it gave us an 11 on the femur, 9 for the AL and 7 for the PM, so we did actually have to use 3 different FlipCutters for this.
Notice the blue FibreTape that is reinforcing the AL bundle, and I’ll show you how we do that in my next lecture, and that’s used then for back up fixation, which I think is fantastic for PCL reconstruction whether you do GraftLink or TriLink what we get on the table is not always what we see at three months and it can be very disappointing to have this fantastic result when you leave the operating theatre, but with the forces of the tibia forcing that graft over a 3 or 4 month period you re-examine the patient and they have a laxity that they didn’t have when they left the operating table. FibreTape stops that - by using the internal brace concept we can get round that.
In terms of making the sockets on the femur; rather than drilling from inside to out we use the FlipCutter, and again this is very easy to do to make these sockets. There’s the AL socket and then we came in and made our PL socket, and again, very, very straightforward to do.
I think one of the big advantages of using either GraftLink or TriLink is getting the passage on the tibial side…getting the graft to go into the tibial socket, it’s so much easier than pulling it up through a complete tunnel on the tibia and it really does just fly in, it makes this a very easy part of the procedure, and then we can fine tune and we can tension on the tibia and we can tension on the femur and really get that graft to exactly where we want.This is the final picture of this PCL case, so first the PL bundle going in and then pulling in on the AM, and it’s early days but this patient is extremely well, the patient went home the next day which – you’re used to that in the States – but for us, my PCLs were staying in for 3 days routinely because of…with the traditional technique that I was using... so without changing anything my patients are now going home the next day with the all-inside technique.
So this is what we do for backup, so again you see the FibreTape.This is the graft – this is actually showing it for a PCL case that was an ACL graft, short graft – so I’m then taking that FibreTape and then inserting that distally to give me back up fixation and this really works well for the PCL.
So, in terms of results, we’ve done 16 cases, we’ve done, as I say, one PCL, several have been for multiligament.
And the scores have been great. Now it’s only a year – it’s early days – but I think the TriLink works extremely well.The procedure is anatomic, it’s making use of all of the all-inside principles; so we are going single on the tibia, double on the femur and using the TightRope cortical suspensory fixation devices, and it really is soft tissue preserving, you can do these procedures 1 allograft or 1 semi-T, it’s bone preserving and you get an excellent size graft.
Just like to acknowledge my Fellows and thank you very much.