Anatomical Study of the Medial Region of the Knee: Qualitative, Quantitative Analysis and Description of the Anterior Oblique Ligament

Objective To describe all ligamentous, capsular, tendinous and bone landmarks structures of the medial region of the knee, as well as a new ligamentous structure identified in a series of anatomical dissections of cadaveric specimens. Methods Twenty cadaver knees were dissected to study the medial compartment. The main structures of this region were identified during dissection. The morphology of the structures and their relationship with known anatomical parameters were determined both qualitatively and quantitatively. The collected data were analyzed and interpreted using descriptive statistics. Results In the dissection of all specimens, all ligamentous structures previously described in the anatomical study of the medial part of the knee were identified, and objective measures that can help as parameters for surgical ligament reconstruction were identified. When dissecting the medial collateral ligament, a bony prominence immediately distal to its proximal tibial insertion was observed and described, as well as a bursa below the ligament, in which it was not inserted. We also described a ligamentous structure with extracapsular location, originated anteriorly to the medial epicondyle and following obliquely towards the tibia. These structures were named, respectively, interinsertional tubercle, interinsertional bursa and anterior oblique ligament. Conclusion In addition to the description and measurement of the structures and parameters already existing in the anatomical study of the medial part of the knee, it was possible to describe three new structures not yet described in the literature: the interinsertional tubercle, the interinsertional bursa, and the anterior oblique ligament. These structures were found in all dissections performed.