This article is more than 5 years old. Information may no longer be current.

Anatomic ACL reconstruction restores rotational knee stability

Preliminary results of the first 100 cases seem promising.

Issue: November 2004

ByFreddie H. Fu, MD, DSc(Hon), DPs(Hon)

Add topic to email alerts

Receive an email when new articles are posted on

Please provide your email address to receive an email when new articles are posted on .

Subscribe

Added to email alerts

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

Back to Healio

We were unable to process your request. Please try again later. If you continue to have this issue please contact customerservice@slackinc.com.

Back to Healio

Surgical anterior cruciate ligament reconstruction has become one of the most common procedures in sports medicine, and the reported clinical outcomes following ACL reconstruction are usually satisfactory. In certain cases, however, patients may have persistent complaints and do not return to their previous activity level. For that reason, we should continue to critically evaluate the clinical outcomes following ACL reconstruction. Further improvements in the treatment of the ACL-injured patient are necessary to optimize the clinical outcomes. The following article will introduce a new concept of anatomic ACL reconstruction and restoration of rotational knee stability.

The ACL originates from the lateral femoral condyle on its medial surface and inserts anteriorly on the proximal portion of the tibia. Anatomic studies demonstrated that the ACL is not a single cord, but it is a collection of individual fascicles. The anteromedial bundle originates from the proximal aspect of the femoral attachment and inserts on the anteromedial aspect of the tibial attachment. The posterolateral bundle originates more distally and anteriorly on the femoral site and inserts onto the posterolateral aspect of the tibial attachment. The posterolateral bundle tightens with knee extension, whereas the anteromedial bundle tightens with knee flexion.

Complete ruptures of the anterior cruciate ligament may lead to persistent knee instability, meniscal tears and articular cartilage degeneration. Thus, ACL reconstruction has become one of the most common procedures in sports medicine. The majority of ACL reconstruction techniques focus on replacing the anteromedial bundle of the ACL (single bundle technique) while the posterolateral bundle is usually not reconstructed. A careful review of the literature reveals that as many as 90% of the patients may benefit from surgical ACL reconstruction. In some cases, however, complaints of knee pain, instability and giving-way may persist. Thus, the question arises how the clinical outcomes following ACL reconstruction can be further improved.

Restores knee kinematics

Recent cadaveric studies from our laboratories demonstrated that ACL single bundle reconstructions were successful in limiting anterior tibial translation but were unable to provide rotational knee stability. In contrast, combined reconstruction of the anteromedial bundle and the posterolateral bundle of the ACL provides sufficient rotational knee stability and results in a better restoration of the normal knee kinematics (Yagi et al 2002). Based on these data from basic science studies, we have established the concept of anatomic ACL reconstructions at our center. This anatomic ACL reconstruction includes the restoration of both the anteromedial bundle and the posterolateral bundle of the torn ACL. For approximately one year, we have performed anatomic ACL reconstructions, and our preliminary results of the first 100 cases are promising.

The anatomic ACL reconstruction is performed arthroscopically, and we prefer to use two tibialis anterior tendon allografts to restore the two bundles of the ACL. These allograft tendons are doubled and attached to an Endobutton (Smith & Nephew) loop for the graft fixation on the femoral side. The prepared tendon grafts are usually 12 cm to 13 cm long and have a cross-sectional diameter of 7 mm to 8 mm (Figure 1).

Two convergent tunnels are drilled into the tibia (one tunnel for the anteromedial bundle and one tunnel for the posterolateral bundle), and two divergent tunnels are drilled into lateral femoral condyle (one tunnel for the anteromedial bundle and one tunnel for the posterolateral bundle) (Figure 2A-B).

The nomenclature of the two ACL bundles goes by the tibial footprint.

First, the posterolateral graft is passed with the Endobutton loop and flipped in the usual manner. The anteromedial bundle graft is passed after that and fixed proximally with an Endobutton in a similar manner (Figure 3). For the tibial fixation, we prefer the use of staple fixation in combination with a Bioscrew fixation (Figure 4A-B). The posterolateral bundle and anteromedial bundle are tensioned and secured at 45° and 10° of flexion, respectively.

Patients undergoing anatomic ACL reconstruction follow the same rehabilitation protocol as patients undergoing ACL single bundle reconstruction. Our preliminary clinical outcome data show that patients undergoing anatomic ACL reconstruction recover quickly from their surgery and major complications associated with this procedure have not been observed. In our experience, patients undergoing anatomic ACL reconstruction demonstrate great postoperative knee stability with excellent range of motion post-surgery.

I believe that the concept of anatomic ACL reconstruction and rotational knee stability represents one of the most important recent advances in ACL surgery, and the current research activities in my department focus on the further investigation of these concepts. Currently, my research fellows Boris A. Zelle, MD, Peter U. Brucker, MD, and Thore Zantop, MD, are investigating the embryological, anatomical, biomechanical and clinical considerations of anatomic ACL reconstruction and rotational knee stability.

A major focus of our research will be the development of a valid examination technique for measuring the rotational knee stability in vivo. As of now, we have various techniques for measuring the anteroposterior knee stability, such as the KT-1000. However, examination techniques for measuring rotational knee stability are not well established in the literature. The successful development of such an examination technique will allow us to quantify the clinical long-term outcomes of patients undergoing ACL reconstruction with regard to their rotational knee stability.

A long-term goal of my research group will be to identify the specific importance of the posterolateral bundle for the overall knee stability and to identify the specific patient population that depends on the rotational stability component of the knee.

For more information:

• Yagi M, Wong EK, Kanamori A, et al. Biomechanical analysis of an anatomic anterior cruciate ligament reconstruction. Am J Sports Med. 2002;30:660-66.

• Freddie H. Fu, MD, is chairman of the department of orthopedic surgery at the University of Pittsburgh School of Medicine.