Anterior Cruciate Ligament Tibial Footprint Anatomy: Systematic Review of the 21st Century Literature

Purpose: The purpose of this study was to systematically review current arthroscopic and related literature and to characterize the anatomic centrum of the anterior cruciate ligament (ACL) tibial footprint. Methods: On January 31, 2011, 2 independent reviewers performed a Medline search using the terms "anterior cruciate ligament" or "ACL," "tibia" or "tibial," and "anatomy" or "footprint." We included anatomic, cadaveric, and radiographic studies of adult, human, ACL tibial anatomy. Studies not published in the English language, studies published before January 1, 2000, and review articles were excluded. References of included articles were also searched according to our inclusion/ exclusion criteria. Included studies were subjectively synthesized, to define the anatomic centrum of the ACL tibial footprint. Results: The Medline search produced 1,224 articles. After application of our inclusion and exclusion criteria and additional search of article references, 19 articles were included and systematically reviewed. With regard to arthroscopically relevant landmarks, (1) in the anterior-to-posterior plane, the anatomic centrum of the ACL tibial footprint as a whole is 15 mm anterior to the posterior cruciate ligament (PCL), the anatomic centrum of the anteromedial bundle is 20 mm anterior to the PCL, and the anatomic centrum of the posterolateral bundle is 11 mm anterior to the PCL and (2) in the medial-to-lateral (ML) plane, the anatomic centrum of the ACL tibial footprint as a whole is two-fifths the ML width of the interspinous distance, the anatomic centrum of the anteromedial bundle is one-half the ML width of the interspinous distance, and the anatomic centrum of the posterolateral bundle is one-fourth the ML width of the interspinous distance. Conclusions: Our results show that the anatomic centrum of the ACL tibial footprint is 15 mm anterior to the PCL and two-fifths the ML width of the interspinous distance. Clinical Relevance: This systematic review of basic science studies may have clinical relevance for surgeons who believe that anatomic ACL reconstruction can result in improved outcomes.