History of ACL Repair
There has been a recent resurgence of interest in the procedure of ACL Repair (as opposed to 'ACL reconstruction), and this is due to improvements in imaging and the way we can visualise the ACL, as well as advances in surgical instrumentation and technique, and improved rehabilitation.
Refer to ACL Repair Medi 2016 ppt
From an historical perspective ACL Repair is not a new idea - two of the great names in surgery, Mayo and Robson, carried out open repair of the ACL and PCL in a miner in 1895! Many years later -
- in the 1950s O'Donoghue - a name very closely associated with sports knee injuries - carried out open repairs of the ACL stump, and immobilised the patient for 4 weeks in flexion.
- in the 1970s, Marshall attempted to pass multiple suture loops through the stumps, and passed these through bone tunnels
- John Feagin at West Point in the '70s at the military academy performed ACL repair on 30 cadets, and 25 out of 30 were doing well at 2 years. However, there was a 94% failure at 5 years.
- In the 1980s, in a randomised controlled trial, Odensten compared repair versus non-operative management. He found 95% had a stable knee if repaired versus only 11% if they were treated non operatively.
- Another randomised controlled trial in the '80s by Sandberg - again comparing repair with non operative treatment - found a significantly increased pivot shift in the non-operated group (which is the measure that we have for instability) compared to 28% in the repair group.
So the results were OK but they were not brilliant, and repair at that point died a death and ACL reconstruction was born. Reconstruction involves removing the existing ACL and making tunnels and sockets and putting in a graft or a new ACL made from the patient's own tissue or donated tissue - autograft or allograft - to replace what was torn.
So why persevere with ACL repair?
The issue with these historical papers is that these were really quite extensive operations, because they were 'open' techniques with a high morbidity. The techniques were used on 'all-comers' without selection. They did not choose the type of patient who we now recognise would benefit from repair - ie someone who has torn the ACL proximally from its attachment on the thigh bone (the intercondylar notch of the femur, which is its origin). Also the rehabilitation was prolonged and in plaster, so that patients couldn't do well when there was no reinforcement or augmentation.
On the other hand, things were not perfect either with the alternative procedure of reconstruction -
- Surgeons remove most of if not all of the existing ACL tissue, which takes away, of course, good tissue that has a blood supply, has innervation, particularly proprioception (which is a very important part of knowing where a joint is at any particular time).
- Another problem is that of 'tunnel widening' which makes further procedures difficult and often they have to be done in two stages.
The instruments that we have now available to us allows us not only to see inside the knee and achieve an excellent level of visualisation with the cameras and the 4K advances in the camera technology, but we also have developed special tools to handle the tissues inside joints and particularly inside the knee. This allows us to manipulate the ACL and pass suture material - previously when this was attempted in the late '70s they had very primitive suture material and now we have very strong sophisticated new materials to not only stitch the ACL back to where it came from but also hold it there. The idea of this technique is to use a so-called internal brace to hold the ACL repair appropriately such that we can carry out the procedure.
Adrian Wilson
The way I explain proprioception to patients is 'if you close your eyes and lift your hand up, and wiggle your finger, you know exactly where it is with your eyes closed because of these 'proprioceptors' that sit in the joints and the ACL is full of proprioceptors and removing the ACL has been shown scientifically to remove the proprioception that we need for joint position sense, so it makes a big difference.
Paediatric ACL injury represents 3% of all ACL injuries, but this is rising, and there are additional challenges with regards to the growth plate in children. In this age group there is also a significant re-rupture or failure of a reconstructed ligament. Our team's paper on 'Paediatric ACL repair reinforced with temporary internal bracing' is the first paper to present on ACL repair in children - and we are very happy with our early results.