Anterior Cruciate Ligament Reconstruction Using a Flexible Reamer System: Technique and Pitfalls

Abstract

Anatomic reconstruction of the anterior cruciate ligament (ACL) has been shown to improve stability of the knee, particularly rotational stability, potentially leading to superior clinical outcomes and a shorter return to sport. Nonanatomic ACL reconstruction has been linked to graft failure and abnormal cartilage loading thought to contribute to progression of degenerative joint disease. Use of the far anteromedial portal (FAMP) to uncouple the tibial and femoral tunnels has led to improved reproduction of the femoral footprint and facilitates drilling of the femoral tunnel in an anatomic position. The use of the FAMP and straight reamer systems introduces its own set of potential complications, including short femoral tunnels and peroneal nerve injury. These potential complications have been addressed by drilling the femoral tunnel in a hyperflexed position, which can lead to difficulty with positioning the operative extremity, visualization, and identification of anatomic landmarks. The purpose of this case report was to review the advantages and technical aspects of using a flexible reamer system and the FAMP to achieve an anatomic ACL reconstruction while avoiding potential complications and pitfalls. Flexible reamer systems allow an additional way of uncoupling the tibial and femoral tunnels to clearly visualize and establish an anatomic starting point within the femoral footprint of the native ACL while avoiding the complications associated with knee hyperflexion and straight reamers with the far anteromedial portal. In the authors' experience, an anatomic reconstruction of the ACL can be achieved safely using flexible reamers while avoiding some of the difficulties seen with straight reamers used in conjunction with an uncoupled, far anteromedial approach.

Keywords: ACL reconstruction; anatomic ACL reconstruction; far anteromedial portal; flexible reamer.

Figure 1.

Position of the far anteromedial portal. Spinal needle entering just superior to the anterior horn of the medial meniscus and passing just anterior to the medial femoral condyle.

Figure 2.

Bony anatomy of the lateral femoral condyle and anterior cruciate ligament femoral footprint demonstrated with a curved curette positioned within the anteromedial bundle footprint, just inferior to the lateral intercondylar ridge and slightly deep to the bifurcate ridge.

Figure 3.

Offset guide, nitinol wire, and flexible reamer with eccentric cutting flutes (VersiTomic Flexible Reaming System; Stryker).

Figure 4.

View obtained from the tight anteromedial parapatellar portal using a 30° arthroscope with knee flexed to 110°. The offset flexible reamer guide is passed safely by the medial femoral condyle under direct visualization.

Figure 5.

The offset flexible reamer guide used to place the flexible guide wire at the chosen anatomic location of the femoral tunnel.

Figure 6.

Knee flexed to 110° for the placement of the flexible guide wire and reaming of the femoral tunnel demonstrating the correct anterolateral exit trajectory of the flexible guide wire with the knee flexed to 110°. Approximately 2 to 3 cm of guide wire exiting the lateral thigh keeps adequate nitinol wire medially out the far anteromedial portal (FAMP) to avoid kinking and breakage of the flexible reamers.

Figure 7.

Arthroscopic view from the tight anteromedial parapatellar portal demonstrating passage of the eccentrically fluted (cutting flutes directed away from the articular surface) flexible reamer under direct visualization, taking care to avoid iatrogenic damage to the medial femoral condyle.

Figure 8.

View down the femoral tunnel from the far anteromedial portal with a 30° arthroscope demonstrating an intact posterior wall and far cortex.