The meeting of ESSKA at the start of May 2016 in Barcelona spent some time focusing on the issue of the ALL (antero lateral ligament) and its role in knee stability. This is the latest hot topic in ACL injury.
Since Steven Claes et al. published their dissection of the ligament in the Journal of Anatomy in 2013 there has been an explosion of interest in this area. Of course it brought to mind the original work of Segond in 1879 and his description of the fracture of the lateral side of the lateral tibial condyle in association with an ACL tear. While controversy still persists on the location of the femoral attachments and even the significance of the ligament itself, there seems to be a general consensus that structures on the antero lateral part of the knee are important in controlling the pivot shift phenomenon seen in ACL tears.
Indeed surgeons who have experience with ACL surgery will be well aware of the failure of a standard ACL repair to control rotatory instability in a lot of cases and the disappointing results of surgery in about 15 % of patients.
The debate goes on between those who feel that the Antero Lateral Ligament is a ligament only created by careful dissection in the specimen lab and is not an actual ligament, those that believe the ALL is an important anatomical structure and actually exists and also those who feel that the attachment of the Ilio Tibial Band on the lateral side of the knee is most important.
It was particularly interesting to listen to the contributions of Mr Andy Williams (the Chelsea team surgeon) and Prof Andrew Amis of Imperial College London. They have shown in their laboratory that the ALL is not an important stabiliser of rotation in the knee but it is the ITB and its attachments that are most important.
This work has changed the thinking in this area. The ALL explained the pivot shift and reconstruction of the ALL seemed to be a logical solution to the problem of rotatory instability in the ACL deficient knee. We are now left with some conflicting and confusing information. Mr Williams and Prof Amis propose a tenodesis on the lateral side of the knee using a middle 10mm strip of the ilio tibial band. This strip is passed deep to the proximal part of the lateral collateral ligament and then attached to the lateral side of the femur proximal to the femoral attachment of the LCL. They do not agree with a reconstruction of the Antero Lateral Ligament.
What seems to be clear is that in about 1/3 of ACL deficient knees there is rotatory instability with a Grade 3 pivot shift or even a pivot clunk. In these knees the ACL reconstruction cannot go it alone and the knee needs to be stabilised on the antero lateral side. This can be done with a graft of the ALL or a repair / reefing of the ALL. Now for the high grade pivot shifts in a primary repair and for the persistent symptomatic pivot shift in the ACL reconstructed knee the ITB tenodesis is also a viable option to correct this problem.
This is an evolving area and there is no doubt that there is more research to come before a definitive answer emerges. The work of Steven Claes in 2013 reignited interest in this are and now the work of Andy Williams and Andrew Amis has given us more to think about.
What has come from this debate is the general acceptance now that the antero lateral structures are important in stability, that in a significant number of cases the ACL graft cannot go it alone and that a repair of the antero lateral structures has been defined.