Intraoperative: Surgical Technique

Introduction

Modern techniques in anterior cruciate ligament reconstruction (ACLR) continue to evolve as surgeons endeavor to restore the anatomy and kinematics of the native knee. Among the reported complications associated with ACLR, tunnel malposition has been recognized as the most commonly observed technical error. ^{, ,} Although errors in the femoral tunnel position are the most frequently reported technical errors in ACLR, tibial tunnel malposition can occur as well. Tunnel malposition can have a number of deleterious consequences, including iatrogenic chondral and meniscal injury, restricted knee range of motion, and inadequate restoration of sagittal plane and/or rotatory stability, which may increase the likelihood of graft rupture. ^{, , , , ,}

The purposes of this chapter are to: (1) review the relevant anatomic relationships pertinent to anatomic ACLR, (2) offer strategies to mitigate the likelihood of femoral and tibial tunnel malposition, and (3) describe techniques that can be employed intraoperatively to deal with tibial and femoral tunnel malposition once recognized.

Visualization is Key: Three-Portal Knee Arthroscopy

The avoidance of tunnel malposition is contingent upon the surgeon obtaining adequate visualization of each patient’s unique anatomy and injury pattern. This process begins with correct placement of the arthroscopic portals. The anterolateral portal should be placed just lateral to the lateral border of the patella tendon and at the level of the inferior pole of the patella ( Fig. 7.1 ). Placing the anterolateral portal as proximal as possible provides the surgeon with a “bird’s eye” view of the tibial insertion of the anterior cruciate ligament (ACL). Additional portals are subsequently placed under spinal needle visualization. The medial portal is created so as to accommodate the proper angle of attack for instruments used for preparation of the medial wall of the lateral femoral condyle and drilling of the femoral tunnel, while avoiding iatrogenic damage to the articular surface of the medial femoral condyle. A more central, anterior portal is placed in line with the midpoint of the tibial remnant of the ACL. Once placed, the central portal can be used to more directly visualize the intercondylar notch, the femoral remnant of the ACL, and the back wall of the lateral femoral condyle ( Fig. 7.2 ). Viewing through this portal, guide pin insertion and femoral tunnel drilling are accomplished without obstruction from the lateral femoral condyle, in many cases obviating the necessity for an aggressive notchplasty and ensuring appropriate tunnel position on the wall. More broadly, this three-portal technique provides the surgeon with an enhanced perspective on all relevant intraarticular structures and allows for a precise understanding of the patient’s unique anatomy.