Anatomic Anterior Cruciate Ligament Reconstruction with Quadriceps Tendon Autograft
Keywords
• Anterior cruciate ligament • Quadriceps tendon • Autograft • Harvest
Key Points
Introduction
Blauth1 first described use of the quadriceps tendon for ACL reconstruction in 1984. The original description of this technique describes a double-bundle reconstruction, by which the central third quadriceps tendon is harvested with a bone block from the superior pole of the patella. The bone block was then fixed within the tibia; 1 bundle was fixed to the medial wall of the lateral femoral condyle and the other bundle of the quadriceps tendon was fixed in the over-the-top position. Staubli and colleagues2 elaborated on this technique, including fluoroscopic evaluation and the development of a press fit, outside in modification. This technique was further popularized because studies reported biomechanical advantages and good clinical outcomes comparing the patellar tendon and quadriceps tendon grafts.2–4 Harvesting quadriceps tendon grafts showed promise, with less apparent anterior knee pain when compared with patellar tendon grafts.5,6 Still, a risk of patellar fracture exists not only during harvest but as a result of the defect within the patella postoperatively.6 Fulkerson and Langeland7 later described harvesting of the central third quadriceps tendon as a free-tendon graft, thereby reducing the morbidity of harvest regarding anterior knee pain and patellar fracture.5 The effect of patellar tendon and quadriceps tendon graft harvest on extensor mechanism strength has not been clearly answered, because some studies show an apparent benefit for quadriceps tendon harvest, whereas others show no difference.8,9
Anatomy and biomechanics
Anatomy and Biomechanics of the Native ACL
The ACL originates on the medial wall of the lateral femoral condyle. Osseous landmarks have been described to improve anatomic ACL reconstruction.10 The lateral intercondylar ridge identifies the anterior border of the ACL, whereas the bifurcate ridge marks the junction of the AM and PL bundles. The AM and PL bundles are named for their relative insertion on the tibia. Anatomic landmarks used to locate the tibial insertion of the ACL include the intercondylar eminence, anterior horn of the lateral meniscus, and the posterior cruciate ligament. The insertion of the ACL is variable, especially with regartd to the orientation of the AM and PL bundles. As a result, preserving the ACL remnant can aid in determining tunnel position, and may be even more important when a double-bundle reconstruction is planned.11
Anatomy and Biomechanics of the Quadriceps Tendon
The quadriceps tendon is formed by the tendinous insertion of the anterior thigh musculature, with the central third primarily consisting of a confluence of the rectus femoris and vastus intermedius. The resultant insertion maintains this relationship by maintaining a natural plane within the tendon. This division within the tendon can be useful, especially in double-bundle ACL reconstructions. The quadriceps tendon inserts directly onto the anterior half of the patella in an oblique orientation.3 The quadriceps tendon has an average thickness of 8 mm, which is nearly twice the thickness of the patellar tendon and more closely replicates the dimensions of the native ACL. Furthermore, the quadriceps tendon has shown similar biomechanic properties, capable of exceeding those of the intact ACL (Table 1).4,12