INSERTION-SITE ANATOMY OF THE HUMAN MENISCI - GROSS, ARTHROSCOPIC, AND TOPOGRAPHICAL ANATOMY AS A BASIS FOR MENISCAL TRANSPLANTATION

A cadaveric study was performed to determine the insertion-site anatomy of the human menisci, their topographical relationships to adjacent intra-articular structures, and which arthroscopic portal provides for optimal visualization of each insertion site. Fifteen fresh-frozen cadaver knees were studied (ages 48 to 63 years). Ten knees underwent arthroscopy using four standard arthroscopic portals. Visualization and placement of an arthroscopic guide over each meniscal horn insertion site was attempted through the four arthroscopic portals. Guide wires were drilled to mark horn insertions followed by a gross dissection to evaluate accuracy of the guide wire placement and to isolate meniscal horn insertion sites. Insertion sites were outlined and evaluated for size and topographical relationships to other intra-articular structures. Five additional knees were dissected free of all soft tissues except the tibial insertions of the meniscal roots and anterior cruciate ligament/posterior cruciate ligament. Each tibia was mounted in a jig and a digitizing system was used to record coordinates of points along the outline of each bony meniscal horn insertion site, the ACL tibial insertion, and the articular surface of each tibial plateau, The x, y, z coordinates for each point were calculated and loaded into a computer program allowing for surface area determination and computer-generated topographical maps to assess relative position of each specific insertion site, Placement of the arthroscope in the anterolateral portal allows optimal visualization and guide wire placement for both lateral meniscal horn insertion sites. Medial meniscal anterior and posterior horn insertion sites are best visualized with the arthroscope in the anteromedial and posteromedial portals respectively. Each meniscal horn was found to have an anatomically distinct bony insertion site with characteristic acid consistent landmarks defining its margins. The anterior horn of the medial meniscus has the largest insertion, two times greater than that of the posterior horn of the lateral meniscus. Statistical analysis showed medial horn insertion sites to be greater than lateral insertions and for the medial meniscus, anterior horn insertion sites larger than posterior horn insertion sites (P < .05). Whereas the ''footprint'' of the anterior horn insertions are relatively planar, the posterior horn insertions are significantly more complex in three dimension. In conclusion, we have provided data on the relative sizes, shapes, and locations of the human meniscal bony insertion sites-a critical prerequisite needed before performing meniscal reconstruction.