The primary ACL reconstruction surgery can fail due to a number of reasons. This can be due to a recurrence of trauma despite being no other factors within the knee itself. This is very unfortunate and does however happen. An athlete can make a full recovery from the primary surgery and go back to sport and have a further injury that can re-rupture the ACL. This can be simply coincidental and unfortunate or sometimes can be due to a too early return to sport or lack of tone, strength and conditioning of the muscles in the leg predisposing to injury.
Other factors that can result in re-rupture of the ACL and reconstruction surgery are surgical and technical factors. These can range from poor tunnel placement, small graft size and missing other structural injury at the time of primary surgery, for example meniscal tears, meniscal ramp lesions or other ligamentous instability. If there are other structures that are injured in the primary injury and not addressed as part of the primary ACL reconstruction, this results in instability in other parts of the knee that can predispose the ACL reconstruction to re-rupture and failure.
Revision ACL surgery can be a one or two stage operation. This depends on the individual and their personal circumstances. There are many factors that need to be addressed in order to make sure that a further re-rupture does not happen. A complete examination and investigation work-up is carried out as well as an appropriate prehabilitation programme. CT scans and MR scans are carried out to look at the placement of the previous tunnels and whether any other tissues have been injured that require surgery at the same time.
A single stage revision is where everything is removed from the primary surgery and a full revision reconstruction is carried out. This is possible when the initial bone tunnels that were drilled are small in diameter and in the correct place and no bone grafting of the femur or tibia is required.
A two-stage operation is required when the first bone tunnels that were drilled are very large or they are in such a position that requires bone grafting in order to gain a stable bony bed in order to be able to place the revision graft securely within the knee. During the first stage of the operation all of the previous hardware, for example buttons and screws etc are removed. The bone tunnels from the first surgery are bone grafted with impaction grafting and the knee is allowed to settle down with physiotherapy. CT scans are carried out at three and six months to ensure that the bone grafting has incorporated. Once the bone grafting has fully incorporated we can proceed to the second stage.
The second stage reconstruction is carried out once we have restored the bony anatomy around the femur and tibia to allow the second stage of the procedure to be carried out. The appropriate graft is selected and prepared and new bone tunnels are drilled and the graft is passed and secured using buttons plus/minus an interference biocomposite bone screw. At the same time other structures are repaired, for example the meniscus and we prefer to reconstruct the anterolateral ligament during revision surgery to reduce any instability in the knee and therefore minimising the risk of re-rupture.
The postoperative rehabilitation is similar to the primary ACL reconstruction. This depends on which structures have been reconstructed and repaired and whether the patient requires a brace and crutches to mobilise. If any meniscal repair has been carried out then crutches and a brace are usually required for around six weeks. The rehabilitative process is similar to that described for an ACL reconstruction and is carried out by an experienced physiotherapist.
However, due to the nature of the revision surgery, it is recommended to spend longer on the rehabilitation. The research suggests that a minimum of 14 months before a return to full sport, or even longer if possible.
We do understand the need to return to full activity as soon as possible, but our focus is on long term success and the avoidance of further surgery.