The meniscal insertion of the knee anterolateral ligament

Purpose The aim of this study is to characterize in detail the meniscal insertion of the anterolateral ligament (ALL) of the knee, establishing parameters regarding the circumference of the lateral meniscus and the popliteal muscle tendon (PMT) groove in addition to its histological analysis. Methods A total of 33 knees of cadavers were dissected. The ALL and the lateral meniscus were removed en bloc. After removal of the anatomical specimen, the meniscus circumference, the ALL insertion points on the external surface of the lateral meniscus, and the PMT groove were measured. Eight menisci were subjected to histological analysis. Results The ALL was found in all dissections performed. The ALL insertion occurred macroscopically in the transition between the anterior horn and the lateral meniscus body, specifically beginning at 36.0 % and ending at 41.9 % of the meniscal circumference, occupying a mean area of 5.6 mm. The distance between the end of the ALL meniscal insertion and the beginning of the PMT groove averaged 12.9 mm. In the histological evaluation, in longitudinal sections, we observed dense collagen fibers of the ligament inserting on the external surface of the meniscus. It is possible to observe a spreading of collagen fibers at the moment of meniscal insertion. Conclusions The ALL meniscal insertion was found in all dissected specimens, beginning with approximately 36 % of the meniscal outer diameter, 12.9 mm anterior to the beginning of the PMT groove. The histological analysis confirmed the presence of true ligamentous tissue in the dissected specimens.