What is a revision (redo) pediatric ACL Reconstruction?
A revision pediatric ACL reconstruction needs to be performed when an initial ACL reconstruction fails. Sadly, despite the amazing ability of children to heal injuries – they have the highest risk of failure of any age group following ACL surgery. Even a perfectly performed ACL reconstruction can fail but identifying the causes and contributors to an ACL graft failure are the key to achieving success the second (or third….) time around. There are several potential factors that lead to failure of an ACL reconstruction and choosing a team that is skilled and experienced in revisions is critical. Failing to address these causes can lead to failure again – and this can be devastating to an athlete.
Potential causes/contributors to graft failure:
Technical: Graft tunnel position needs to be anatomic and failure to recreate the anatomy can put abnormal loads across a reconstruction.
Biologic: It is undisputed at this point that allografts (cadaver grafts) do not perform well in kids. They have a 3-4x higher failure rate and with rare exception should be avoided. Despite this, some providers still use these grafts in kids and failure is not uncommon. We favor patella tendon grafts in skeletally mature children or quadriceps tendon autografts in skeletally immature children.
Associated Other Ligament Injury: In addition to the ACL, there are a variety of other ligaments in the knee that provide stability. The FCL, PLC, MCL and PCL can be compromised with the initial injury. Left untreated, laxity (looseness) in these structures can put undue strain on the graft resulting in stretching or tearing. The function of these ligaments can be assessed with a thorough physical exam but often stress x-rays are required to fully assess their competence.
Alignment: There is increasing awareness that bony alignment is associated with ACL injury and specifically ACL tear. Failure to evaluate alignment and tibial slope can result in failure of a revision reconstruction.
Meniscal Status: The menisci and meniscal roots have an important role in stability of the ACL reconstructed knee. It is common for a failed ACL to have had previous meniscal surgery and meniscal deficiency or root dysfunction can coexist in this setting.
Rehab: Although the technical parts of ACL surgery are important, the therapy that ensues is just as important. Failure to complete the entire ACL rehab and pass a return to sport test can put an athlete at risk for failure.