"Three advances are dominating my thinking right now when it comes to ACL tears in children:
- primary repair with internal bracing
- the 'all-ephiphyseal approach, and
- the use of allograft from the mother."
Primary repair with internal bracing
In young children with an anterior cruciate ligament injury I am using Gordon Mackay’s technique of ACL repair with internal brace. I first pass what is called a FibreLink suture, using a very cleverly devised device around the existing ACL tissue that gives control of the ACL, and allows the ACL to be pulled back onto the femur where it has torn away. We then go on to do the drilling, and because we are only passing very small sutures it is possible to do this surgery through just 2.4 mm tunnels.
I was referred a 5 year old two years ago, and this little girl had a complete tear of her ACL. Using X-ray or fluoroscopic control I made a 3 mm drill hole underneath the physis in the epiphyseal area or end of the femur and on the tibia used a 3 mm drill, coming vertically through the middle of the physis - which is an accepted technique and minimises the risk of an injury. As I refined the technique and with my next small customer, this time a 6 year old boy, I was able to do this through 2.4 mm drill holes and kept both tunnels well within the epiphysis and below the physis on the femur and above the physis on the tibia, using a so-called 'all-epiphyseal' technique. This means that there is literally no risk to the growth plates. Having passed the suture initially around the ACL, the repair suture is taken up the femoral tunnel and then the internal brace - which is comprised of a fixation device called the 'ACL TightRope' - essentially a button with some nylon - and looped around the nylon in a loop on this button goes strong nylon tape, which is just 2 mm in diameter. It is called FibreTape. This makes up the so-called 'internal brace' which is pulled in from the femoral side, and the button is docked on the femur, and the tails of the internal brace taken down through the two tunnels that have been made and across the native ACL. When the button is nicely docked, the knee is taken into full extension and the fixation is then achieved on the tibial side with a very small plastic screw, caled a SwivelLock.
The little girl who was five (now seven) is now out to two years and is beginning to surf. She has relocated with her family to Cornwall and reports a normal knee. We have objective scoring - the Koos score was 100/100 on subjective reporting, and we also measured her knee with a knee laxity device and found less than 2 mm side-to-side difference, which essentially means that it is normal.
I also had the opportunity to look inside this little girl's knee at 3 months from the initial procedure and was astounded how well the ACL had healed.
In the young boy's case, he is now one year out and also reports a normal knee. He hasn't returned to football yet because his mother is still concerned and apprehensive about him doing contact sport, which is something he wants to do. Again I measured him with the KIRA, which is a new device that we are trialling for assessing knee laxity, and again the side-to side difference was less than 2 mm, which is really quite exciting.
The 'all-epiphyseal' 'all-inside' approach
This is used in paediatric cases when there is insufficient tissue to do a repair, and making an appropriately-sized tunnel using cleverly designed tools (which I have actually helped to develop along the way) we are able to drill below the physis on the femur and above the physis on the tibia, doing a so-called 'all-epiphyseal' ACL procedure. By doing this we take out the really big risk of growth plates injury, which is the one thing that surgeons most worry about when carrying out ACL surgery in this small paediatric and skeletally-immature group.
It is done through tiny incisions, the drill holes are tiny, the surgery is relatively easy to perform, so actually the patients recover very quickly.
Use of allograft from the mother
Ideally in children we use their own tissue, but in small children the tissue that we could use can be very thin and 'weedy', and this poses a problem for surgeons.
One way of getting around this is to use allograft, or donated tissue. The best allograft we can get is from a live donor and this technique is pioneered by Leo Pincewski in Sydney, and he has carried out this surgery on a regular basis for the last 20 years, using tissue from the mother or father - taking one of the hamstrings tendons and using this in the adjacent operating theatre for the child.
We have a licence in Basingstoke Hospital to handle human tissue, and therefore are able to offer this service in the UK, and we have done so with great success.
We have a system for safe transferring of the allograft from one theatre to the next, and then carry out the ACL surgery using the all-epiphyseal technique described above.
There are only a handful of centres that have this licence, and as far as I know we are the only centre in the UK offering this service, which is a game-changer in small children where there is inadequate tissue to do a repair.
We are very committed to research and to following up these new techniques and have recently acquired sufficient resource to fund a data analyst, a research coordinator, a research physiotherapist, and all the patients are being very carefully evaluated and followed up as part of our ongoing commitment to develop these exciting new techniques. The results look excellent, and we are hoping to publish our paediatric repair techniques in the very near future.
The ACL Study Group, which is a group of worldwide leading knee surgeons, meets once a year, and will be meeting in the week beginning the 14th of March in Sweden. In the paediatric ACL session these new ideas are being presented as an exciting contribution in dealing with a difficult paediatric injury.
