Individualized Anatomic Anterior Cruciate Ligament Reconstruction

Carola F. van Eck, MD, PhD

Freddie H. Fu, MD

Dr. Fu or an immediate family member serves as a paid consultant to or is an employee of Medicrea – son Gordon; serves as an unpaid consultant to Smith & Nephew; and serves as a board member, owner, officer, or committee member of the American Orthopaedic Society for Sports Medicine, the International Society of Arthroscopy, Knee Surgery, and Orthopaedic Sports Medicine, and the World Endoscopy Doctors Association. Neither Dr. van Eck nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

This chapter is adapted from Macalena J, van Eck C, Fu F: Anatomic anterior cruciate ligament double-bundle reconstruction, in Flatow E, Colvin AC, eds: Atlas of Essential Orthopaedic Procedures. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2013, pp 109-116.

INTRODUCTION

The anterior cruciate ligament (ACL) is a dynamic structure, rich in neurovascular supply and comprised of distinct bundles, which function synergistically to facilitate normal knee kinematics in concert with bony morphology and other ligaments, meniscus, and capsular attachments. Characterized by individual uniqueness, the ACL is inherently subject to both anatomic and morphological variations as well as physiologic aging.

Injury to the ACL is common. Each year, more than 100,000 ACL reconstructions are done in the United States alone.¹ Traditionally, only one of the two native bundles of the ACL is reconstructed. These traditional “single-bundle” reconstructions place the ACL outside the native insertion site area, in a nonanatomic position.²^,³^,⁴ They have been shown to return the knee to normal International Knee Documentation Committee (IKDC) scores in only 61% to 67% of patients.⁵ Several studies have shown that Anatomic double-bundle reconstruction better re-creates the native knee kinematics and function.⁶^,⁷ Furthermore, we believe that performing anatomic reconstruction and respecting the native anatomy may improve the long-term health of the knee and decrease the risk of degenerative arthritis.⁸

PATIENT SELECTION

Ruptures to the ACL are diagnosed based on the patient’s history and physical examination. A detailed history is of utmost importance to the diagnosis of ACL injuries. Most ACL ruptures are secondary to noncontact trauma to the knee sustained during cutting or pivoting sports. Athletes frequently report hearing a pop and noticing an immediate effusion.

The physical examination is also important to the workup of athletes with an injured knee. Attention to Lachman and pivot shift testing is very important. In the isolated injuries to the ACL, most cases involve both bundles, but in rare occasions one or the other may be torn. Isolated injuries to the posterolateral (PL) bundle are suggested by the presence of a positive pivot shift test with an intact end point on Lachman testing. Isolated injuries to the anteromedial (AM) bundle are indicated by increased anterior translation without a firm end point on Lachman testing and a negative pivot shift examination. KT-1000 and KT-2000 arthrometer testing (MEDmetric) can be used to further objectify the physical examination.

Contraindications

The senior author’s relative contraindications to anatomic ACL double-bundle reconstruction include the following:

A small femoral or tibial insertion site. Tibial insertion sites smaller than 14 mm will not support the bone tunnels necessary for anatomic double-bundle reconstruction.⁹ This can be determined on MRI preoperatively, but the ultimate decision is made at the time of surgery by arthroscopic measurement of the ACL insertion site. When the insertion site is smaller than 14 mm, an anatomic single-bundle reconstruction is performed.
Notch size of less than 12 mm in the medial-to-lateral dimension.¹⁰^,¹¹ Small notch widths do not allow for the placement of both tunnels, and an anatomic single-bundle reconstruction is preferred.

As with all surgical procedures, absolute contraindications to ACL reconstruction exist. Active infection is

an absolute contraindication to ACL reconstruction, as is malalignment in the setting of a chronic ACL-deficient knee. In knees with a chronic ACL deficiency, any malalignment needs to be corrected before proceeding with ACL reconstruction. Malalignment is best judged on standing pelvis-to-ankle radiographs on a 32-in. cassette. Instability to varus or valgus stress also needs to be evaluated and corrected if present. ACL reconstructions performed in the setting of incompetency of the posterior cruciate ligament, the posterolateral corner, or the medial collateral ligament complex will increase the rate of failure. As with any combined ACL tear with meniscal injuries, the meniscal tears should be treated with either repair or partial meniscectomy as clinically indicated. Chondral lesions should be evaluated and treated accordingly.

FIGURE 1 Algorithm for anatomic single- and double-bundle ACL reconstruction.⁷^,⁸^,¹⁴^,¹⁸^,¹⁹^,²⁰^,²¹^,²²^,²³^,²⁴ ACL = anterior cruciate ligament, AM = anteromedial, PCL = posterior cruciate ligament, PL = posterolateral. (Adapted with permission from van Eck C, Lesniak B, Schreiber V, Fu F: Anatomic single- and double-bundle anterior cruciate ligament flowchart. Arthroscopy 2010;26[2]:258-268.)

PREOPERATIVE IMAGING

Well done weight-bearing heavy radiograph should be obtained when possible. Careful evaluation for changes associated boney avulsions (spine fractures, segond fractures, etc) should be made. MRI is used to evaluate for concomitant ligament injury as well as associated meniscal or chondral pathology. For the senior author, the MRI can also be used for preoperative planning of the ACL bundles and insertion sites. Using special planes, such as the oblique sagittal and oblique coronal planes,¹²^,¹³ both the AM and the PL bundles of the ACL can be adequately evaluated. In addition, measurements of the ACL femoral and tibial insertion sites can be performed. If the senior author also used an MRI of the contralateral knee to assess, the native ACL inclination angle can be measured (Figure 2). We have also found that the preoperative MRI can also be used to determine autograft length and the diameter of the quadriceps and bone-patellar tendon-bone graft.

FIGURE 2 Sagittal magnetic resonance images of the knee, showing a cut through the anterior cruciate ligament (ACL). A, The two-bundle anatomy of the ACL can be observed, as well as the presence of an isolated anteromedial (AM) bundle tear; the posterolateral (PL) bundle remains intact. B, The ACL insertion site is measured on MRI; it measures 18 mm in this patient. C, The inclination angle of the ACL is measured on MRI; it measures 46° in this patient.

VIDEO 18.1 Anatomic Single- and Double-Bundle Anterior Cruciate Ligament Reconstruction. Jeffrey Macalena, MD; Carola van Eck, MD, PhD; Freddie H. Fu, MD (11 min)

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Video 18.1

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