ACL repair augmented with the InternalBrace – a look at the 5-year results
The Mackay Clinic recently presented its five-year-study results of ACL repair augmented with the InternalBrace at the 2019 annual meeting of the American Academy of Orthopaedic Surgeons. (These have now been submitted for publishing). We asked Professor Mackay exactly what the results show and about some of the differences between ACL repair augmented with the InternalBrace compared to a traditional ACL reconstruction.
Q: What do these five-year results show?
PM: They show categorically that there is a place for ACL repair. We have been using InternalBrace augmented repairs for eight years now and our understanding is evolving all the time. These results have changed orthopaedic practice and will continue to do so. Patients should no longer just settle for a reconstruction and repair should be considered in appropriate cases.
Q Are there clear advantages associated with early repair
PM: Yes; early repair has an impact on protecting joint health and restoring normal biomechanical function. An ACL repair augmented with the InternalBrace procedure protects the cartilage, reducing the need for resection. We anticipate that this will minimise the future risks of arthritis. This is already being borne out when we re-examine earlier InternalBrace patients.
Q: How many patients took part in the five-year ACL Augmented with InternalBrace repair study?
PM: 37 patients undergoing ACL repair augmented with the InternalBrace were followed. (NB 3 patients were lost to subsequent follow-up – so the study relates to the remaining 34)
Q: What are you most pleased about with these results?
PM: These results surpass our expectations. We have been able to demonstrate that it is possible to create an environment for ACL healing, following injury, and to restore excellent function to even a severely injured knee. Forty years ago, when repair was first tried, it was considered unsuccessful and alternatives were explored. Modern advances in our understanding of biology and healing mechanisms mean that with the ACL repair augmented with the InternalBrace technique we have been able to revisit the holy grail of healing. This is completely different to these historical attempts at repair and harnesses improved techniques and technology. It has proved to be highly effective in appropriate cases.
Q Why were you so keen to revisit ACL Repair
PM: We started using the ACL repair augmented with InternalBrace technique due to our concerns regarding the high level of arthritis associated with traditional reconstruction, (Reported to be as high as 48% after 10 years), we were hopeful but did not appreciate it would be this successful. Over 80% of the repair patients did not need any form of reconstructive surgery on their knees during the 5 years of follow-up. Those that did still made a tremendous recovery after a second-stage revision procedure using a reduced graft – again supported with the InternalBrace.
Our five-year results outcomes are comparable to traditional reconstruction surgery in some high-risk groups, with a lot less surgical trauma to the knee and without the need for donor tissue from another part of the knee.
Q: How does ACL repair augmented with InternalBrace differ from traditional reconstruction methods?
PM: One of the main differences is that following an ACL injury the joint often needs to be left to settle before a standard reconstruction can be carried out. An ACL repair augmented with the InternalBrace is carried out as soon after the initial injury as possible, meaning that much more cartilage can be salvaged.
The other difference is that ACL repair with InternalBracing is a lot less traumatic for the joint. Repair augmented with the InternalBrace only requires small bone tunnels which take the 2mm InternalBrace. Compared this to the major bone tunnels that need to be drilled during a traditional reconstruction.
Q: Why is early repair important?
PM: The main reason is for the preservation of natural tissues (bone, ligament and cartilage) within the knee. Preserving cartilage is vitally important in terms of the health of the knee and reducing the risk of osteoarthritis in the future.
With traditional reconstruction techniques, the risk of arthritis a decade after surgery is high – even in young patients.
A potential reason for this subsequent arthritis is the sheer size of the bone tunnels needed for a reconstruction. The photo above clearly illustrates that the process of ACL repair augmented with the InternalBrace (right) is a lot kinder to the knee joint than a reconstruction (left), which is important for its long term health.
Often when a surgeon goes into an injured knee after it has been allowed to settle before a standard reconstruction, much of the cartilage is no longer suitable for repair and has to be trimmed off and removed. If we carry out an acute repair of the ruptured ACL, the newly torn cartilage is repaired rather than removed. We know categorically that repairing the cartilage (Meniscus) reduces the risk of osteoarthritis in the future.
Q: What are the other obvious differences between ACL repair augmented with the InternalBrace and traditional ACL reconstruction.
PM: The main thing after an ACL injury is to restore the function of the ACL itself. We as surgeons, myself included, have traditionally used reconstruction as a way of restoring stability but this does involve harvesting tissue from somewhere else in the body – usually a hamstring.
Repair gives patients a completely different experience to reconstruction. ACL repair augmented with the InternalBrace is a simple, shorter, arthroscopic procedure with less pain for the patient afterwards and an accelerated recovery, including immediate mobilisation.
We have known since the 1950s that immobilisation is damaging to joints, resulting in wasting of muscles and ligaments and even that surface cartilage (veneer of joint) can be damaged. The ability to mobilise quickly following InternalBrace repair surgery should improve blood flow, muscle tone, and ligament strength.
Q: Why are patients able to mobilise more quickly following ACL repair augmented with the InternalBrace compared to reconstruction?
PM: After an augmented InternalBrace repair the joint settles more quickly as it is not as traumatised during surgery and the repaired ACL is protected immediately by the InternalBrace, which acts as a seatbelt should the joint be stretched. With a reconstruction, technically you can still mobilise, but you must do it in a guarded way because the graft in a reconstruction weakens at about the 6 to12 week healing mark when revascularisation occurs (essentially the dead graft tissue develops a blood supply and weakens to almost half its strength during this period of re-modelling). Hence the reason reconstruction patients need to go slowly for the first 3 months. ACL repair augmented with InternalBrace patients, on the other hand, are encouraged to return to normal activity, walking, taking stairs etc from day one. The InternalBrace does not stretch and provides a dead stop which holds the healing ACL until it is strong again.
Q: Were the patients included in the five-year results ACL repairs with grafts?
PM: No, the patients involved in this particular set of results were all straight ACL repair augmented with the InternalBrace. There were no graft patients.
Q: So ACL repair augmented with the InternalBrace does not require a graft?
PM: It depends on the nature of the injury and its severity. If the patient is appropriate and if it is a fresh injury then repair alone is usually our preferred option because it gives the best chance of the joint recovering normal function. If there has been a delay however between injury and surgery, or the damage is too severe (for example the ACL is ruptured in the middle) then we carry out a Hybrid Repair.
Q: What is a Hybrid InternalBrace repair and when do you use it?
PM: A Hybrid Repair is used in ACL injury when it is not possible to put the injured ends of the ligament together; in this case, we use a small piece of donor tissue but back it up by augmented with the InternalBrace – hence the term Hybrid Repair. This way we still retain much more of the knee’s natural biology but use either a small Patellar Tendon graft or a small Quadriceps Tendon graft, to act as a bridge between the damaged ends of the ACL.
I prefer not to use a Hamstring Graft routinely but it has a place in specific situations.
Q: Why do you not like using a Hamstring Graft?
PM: A healthy Hamstring is crucial to the health of a knee joint. I might very occasionally use one but only as a last resort because the Hamstrings protect the Cruciate Ligament, stabilise the knee and contribute to performance.
Q: Of these patients on your ACL repair augmented with the InternalBrace, 5-year-study, how many re-ruptured their ACLs?
PM: Six patients suffered a re-rupture – in other words 17.64%
Q: How does this re-rupture rate compare to traditional reconstruction re-rupture rates?
PM: We are not comparing like with like. The re-rupture rate would appear to be comparable but a rupture of a traditional graft is a disaster as you have already used a donor graft and drilled large bone tunnels and it all needs to be taken down and revised. With a repair a re-tear is like a primary injury and reconstruction can be carried out with lower risks and fewer complications.
Q: Were there any significant factors affecting the re-rupture group in this study group?
PM: In this five-year study many of the re-rupture patients were significantly younger and took part in high level, pivoting sports.
Q: Does this therefore, show that an ACL repair augmented with the InternalBrace is not particularly suitable for these younger patients?
PM: On the contrary, we are finding that ACL repair augmented with the InternalBrace is particularly suitable for certain young, active patients. Other individuals would be better suited to early hybrid reconstruction and our understanding of patient selection factors continues to improve. Adding additional support outside the joint could reduce this risk by at least 50% in this high-risk group
Q: Can you explain this further?
PM: What we have subsequently found is that in this group of patients a straight ACL repair augmented with the InternalBrace is sometimes not enough. A simple extra step of also augmenting the Anterolateral Ligament considerably lowers the chance of re-tear in young, active patients. We expect to find in future patient outcome studies that this small extra procedure adds protection against re-rupture rates in this category of patients. At four years, after combined ACL – ALL repair augmented with InternalBracing has reduced the re-tear rate to 5%
Q: Does adding this extra augmentation mean a longer, two-step surgery?
PM: No, augmenting the Anterolateral Ligament with the InternalBrace takes about 10 minutes additional theatre time and they can be carried out as one procedure..
Q: What then are the benefits of augmenting the Anterolateral Ligament with the InternalBrace?
PM: There is good evidence now published to show that one of the reasons that ACL reconstruction fails is that the supportive tissue on the outside of the knee also stretches at the time of injury (in 87% of cases). We know that if we repair the tissue on the outside of the knee as well while doing a traditional reconstruction, that we reduce the re-rupture rate. Exactly the same principle applies to ACL repair augmented with the InternalBrace, especially in high-risk cases. It is especially important in acute injury when the patient’s sport involves a lot of pivoting and turning.
The group from our ACL repair augmented with the InternalBrace – 5-year-results did not have this additional Anterolateral repair. We now know that this additional, 10-minute procedure could bring our re-rupture rates right down and in fact, we confidently predict that future studies will show that the re-rupture rate among our ACL repair augmented with InternalBrace patients could be as low as 5-10%.
Q: If an ACL repair augmented with the InternalBrace does fail is it possible to repeat the repair surgery?
PM: No. The great thing about the InternalBrace is that because it is only a 2mm strip of fibre-tape which does not require large bone tunnels it can easily be removed following re-injury. The repair itself can not be repeated though because the ligament tissue is generally too poor. Because an Internally Braced knee has not had large bone tunnels drilled into it, with all the subsequent damage this entails, the surgeon is working with un-traumatised bone and therefore a traditional reconstruction can still be carried out. The problem with trying to revisit a re-injured – previously reconstructed knee, is that the surgeon is left to deal with a knee that already has large bone tunnels and hardware in it.
Q: So can you reiterate the main difference between an ACL repair augmented with the InternalBrace compared to a traditional reconstruction?
PM: The ACL repair augmented with the InternalBrace is a minimally invasive attempt to avoid the need for a reconstruction. They are not variations of the same procedure.
A repair is all about healing, regeneration and respecting biology. Reconstruction, on the other hand, is at the opposite end of the spectrum – it is about replacement – as you remove the damaged tissue and you replace it with donor tissue, which is dead tissue from another part of the body or harvested from a cadaver.
The beauty of ACL repair augmented with the InternalBrace is that not only does it allow you to operate at an earlier stage it also allows you to protect the joint and treat it much more gently. We are not harvesting tissue or drilling large bone tunnels to position this harvested tissue and we are also not leaving as much hardware within the patient’s knee.
The idea is that we are leaving the patient’s own natural tissue to heal following an InternalBrace repair. Repair is all about restoring the normality of the joint.
Q: One last question, do you ever use Traditional Reconstruction anymore as a first-line of ACL surgery?
PM: The short answer is no. The only time I ever reconstruct is when it is part of a revision procedure, otherwise, I always carry out an ACL repair augmented with the InternalBrace. Even when direct repair is not possible then I try to carry out a Hybrid Repair as discussed earlier, which minimises the amount of donor tissue required, retains the residual ACL stump for vascularity and nerves, and I back it up with the InternalBrace.
In conclusion, the InternalBrace is now used around the world in over 30 countries to augment ligament repairs and reconstructions – with almost 30 body applications. We continue to strive to improve patient care as techniques and technologies evolve.
For those interested, we have published a full-length video of the surgical procedure for ACL repair augmented with the InternalBrace. You can watch this below.