Solving the Mystery of the Antero Lateral Ligament AC01-AC04
Dr. Rathi Sudhakaran,
Professor, Department of Anatomy, Amrita Institute of Medical Sciences, Amrita University, Kochi- 682041, Kerala, India.
Introduction: The cruciate ligaments are essential for the antero-posterior stability of the knee joint. In Anterior Cruciate Ligament (ACL) rupture, though reconstructive surgery is a widely accepted and proven procedure, there is still an unacceptably high re-injury rate. The fact that the rotational instability persists even after the surgical reconstruction of ACL injury has evoked a new interest in the study of the soft tissue structures on the anterolateral aspect of the knee joint. The stability of the knee joint was found to improve dramatically if ACL reconstruction is accompanied with the reconstruction of the anterolateral soft structures of the knee.
Aim: To identify the attachment and observe the measurable parameters of Antero Lateral Ligament (ALL) and its relationship with the adjacent bony landmarks.
Materials and Methods: Twenty six cadaveric specimens of knee joints were collected from the Department of Anatomy, Amrita School of Medicine, Amrita Institute of Medical Sciences, Kochi and were dissected for the anterolateral ligament. Various parameters of ALL in extended knee- the length, width at midpoint and at the femoral-tibial attachments and thickness– were measured. The relationship of femoral attachment of ALL with the lateral femoral epicondyle as well as the tibial attachment with the Gerdy’s Tubercle (GT) and head of fibula were also noted.
Results: ALL was identified in all the 26 cadaveric knee specimens. It was 39.2±7.2 mm in length, 6.5±2.7 mm in width at femoral attachment and 7.4±3.4 mm at tibial attachment, while the thickness was 1.0±0.5 mm. At the femoral attachment it was 7.1±3.4 mm proximal to and 4.0±2.9 mm posterior to the lateral epicondyle while at the distal attachment it was 20.4±3.1 mm posterior to the GT and 21.33±4.6 mm anterior to the head of the fibula.
Conclusion: The ALL was found to be a distinct, supporting anatomical structure on the anterolateral aspect of the human knee. There is a high incidence of ALL lesions in ACL injuries which causes high-grade pivot-shift. The reconstruction of ALL along with that of ACL could lead to a decrease in the re-injury rates. The anatomical descriptions and the morphometry of ALL may be of great value to the orthopaedic surgeons in performing a more effective reconstructive surgery of ACL.