Single-Bundle Anterior Cruciate Ligament Reconstruction: Technique Overview and Comprehensive Review of Results

Abstract

The purpose of this scientific exhibit is to review the single-bundle anterior cruciate ligament reconstruction theory and technique, focusing on technical pearls used to avoid the most commonly encountered errors, and to provide a comprehensive review of outcomes after single-bundle anterior cruciate ligament reconstruction. Avertically oriented femoral tunnel is one of the most common causes of failure after anterior cruciate ligament reconstruction1-3. In this situation, patients may demonstrate a normal result on the Lachman examination but have instability as demonstrated by a pivot shift phenomenon on clinical examination. As opposed to the two-incision anterior cruciate ligament reconstruction, in which the femoral and tibial tunnels are drilled independently of each other, the femoral tunnel position in a single-incision, transtibial technique is dependent on the position and orientation of the tibial tunnel. ### Problem: Instability Due to Vertical Graft When the transtibial, single-incision technique is used for reconstruction of the anterior cruciate ligament, it is possible for surgeons to inadvertently create a vertically oriented graft (Fig. 1). Such a vertical graft may not adequately restore either the translational or rotational kinematic properties of an intact knee. Clinical failure in these patients commonly presents as subjective instability, with a positive pivot shift, despite a negative result on the Lachman test. ### Anatomy: Anteromedial Bundle Provides Anterior Stability and Posterolateral Bundle Provides Rotational Stability To further investigate this problem, the contributions of the anteromedial and posterolateral bundles of the native anterior cruciate ligament have been studied. The anteromedial bundle has been shown to be located more toward the eleven o'clock position in a right knee and primarily provides a restraint to anteriorly directed forces, while the posterolateral bundle is located more laterally near the nine o'clock position and provides restraint to both anterior as well as rotational forces4,5 (Fig. 2). Fig. 1 Arthroscopic image of a vertically oriented anterior cruciate ligament graft in a right knee. This patient …