It is indeed distressing to see so many patients come into our center with failed ACL (and other knee ligaments, including the posterior cruciate ligament, or PCL and posterolateral (refs 6-8) reconstructions). Many times, these individuals have already been through multiple operations - including the failed cruciate reconstruction - and the thought of more surgery is devastating to them. What we have found in our analyses is that frequently the failure is due either to technical error or to a failure to address other damaged knee structures that have an effect on the cruciate ligaments.
I believe it is imperative that, in each case, the reasons for the failure be determined before revision is considered so that optimum management of all of the relevant problems can be undertaken. If the original problems are not corrected, the revision procedures themselves may not be successful. In addition, other problems such as muscle weakness, an abnormal gait (walking) pattern, and a limitation of knee motion must be resolved if possible before the revision. Many patients must undergo weeks or even months of physical therapy to optimize the condition knee joint and leg as much as possible. We have found this increases the potential for a successful outcome of revision reconstruction.
Before launching into the course, it may be a good idea to be quite sure of the terminology and the relevant anatomy, so that we do not lose each other right from the beginning.
Primary ACL reconstruction
The term 'primary ACL reconstruction' is reserved for the first surgical operation undertaken to restore function after an ACL is torn. This is the surgeon's best opportunity to restore normal ACL function and knee stability.
Revision ACL reconstruction
When an ACL reconstruction fails, a decision may be made to remove the first graft and revise the procedure using a new graft. In rare cases, the first graft is left in place and a second graft is inserted. This is called 'revision' ACL surgery. Revision surgery is likely to be more complicated, as considerable time may have passed and muscles may be wasted, bones may be thinned, the joint surface may be under considerable stress, and tendons may already have been 'harvested' for use in the first operation.
The isometric point was deemed to be a point at which ligament fibres remained in the same position during knee motion, and surgeon took care to position the graft in the position accepted as the isometric position. Although you may come across this concept in the literature, I personally (and several surgeon colleagues) no longer refer to the ACL graft as being placed in an 'isometric position'. This change, after many years of talking about isometricity, is due to the fact that all of the ACL fibers are constantly in motion during flexion and extension. Therefore, I now do not believe it is a truly isometric structure.
Depending on the type of graft material used in the reconstruction, and the surgical procedure chosen, different fixation devices (such as screws and staples) are used to fix the graft onto the bone.
Autograft (autogenous graft)
This is a graft that is taken from the patient's own body. The tissue is harvested and immediately implanted into the anatomically correct ACL attachment sites on the femur and tibia. The most common graft sources are the patellar tendon, the hamstring tendons, and the quadriceps tendon.
This is a graft that uses tissue taken from a donor. The tissue is not fresh, but is processed with chemicals to reduce the risk of disease transmission and stored frozen. The most common allografts are taken from the patellar tendon and Achilles tendon.
I am going to leave you to familiarise yourself with the relevant anatomy, and the links in the text as well as the keyword tags at the top of this page will help you to find this information.
Cruciate ligaments and intercondylar notch
It is important to understand the relationship of the cruciate ligaments to one another, and also to appreciate their attachments in the flat upper surface of the tibia and in the intercondylar notch. For instance, the ACL attachment is located on the lateral femoral sidewall of the notch; no ACL fibers extend to the intercondylar roof. ACL grafts which are placed in the "roof" of the intercondylar notch are vertical in orientation, unlike the native ACL, and are therefore prone to failure. The important anatomic positioning means that any graft has to be placed with great precision that replicates where the original ligament was located. (The illustration shows the structures of the right knee from the side. PCL=posterior cruciate ligament).
Collateral ligaments, menisci and meniscal ligaments
The menisci act as spacers and shock absorbers, cushioning the impact between the rounded ends (condyles) of the femur and the flattened end (plateau) of the tibia. They also play a role in knee stability, with the medial meniscus intimately related to its collateral ligaments and the lateral meniscus intimately related to the structures of the posterolateral corner. (The illustration shows the structures of the right knee from the front. LCL=lateral collateral ligament, MCL=medial collateral ligament).
Posterolateral corner & capsule
The posterolateral corner has a complex anatomy that is often poorly understood by orthopaedic surgeons, but an understanding of its anatomy and contribution to knee stability is essential if one is to avoid many of the problems of failed cruciate ligament surgery.
1 Noyes FR, Barber-Westin SD: Anterior cruciate ligament revision reconstruction: Results using a quadriceps tendon-patellar bone autograft. Am J Sports Med 34: 553-564, 2006.
2 Noyes FR and Barber-Westin SD: Revision anterior cruciate ligament reconstruction: Report of 11-year experience and results in 114 consecutive patients. In Instructional Course Lectures, Vol. 50, Sim FH (ed), American Academy of Orthopaedic Surgeons, Rosemont, IL, 2001, pp. 451-461.
3 Noyes FR and Barber-Westin SD: Revision anterior cruciate ligament surgery with use of bone-patellar tendon-bone autogenous grafts. J. Bone Joint Surg. 83-A: 1131-1143, 2001.
4 Noyes FR and Barber-Westin SD: Revision anterior cruciate ligament surgery with allograft and autograft tissues: Experience from Cincinnati. Clin Orthop 325: 116-129, 1996.
5 Noyes FR, Barber-Westin SD, and Roberts CS: Use of allografts after failed treatment of rupture of the anterior cruciate ligament. J Bone Joint Surg 76-A: 1019-1031, 1994.
6 Noyes FR, Barber-Westin SD: Posterior cruciate ligament revision reconstruction, part 1: Causes of surgical failure in 52 consecutive operations. Am J Sports Medicine 33: 646-654, 2005.
7 Noyes FR, Barber-Westin SD: Posterior cruciate ligament revision reconstruction, part 2: Results of revision using a two-strand quadriceps tendon-patellar bone autograft. Am J Sports Medicine 33: 655-665, 2005.
8 Noyes FR, Barber-Westin SD, Albright JC: An analysis of the causes of failure in 57 consecutive posterolateral operative procedures. Am J Sports Med 34: 1419-1430, 2006.