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 anatom y 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 ca daver knees were studied (ages 48 to 63 years). Ten knees underwent ar throscopy using four standard arthroscopic portals. Visualization and placement of an arthroscopic guide over each meniscal horn insertion s ite was attempted through the four arthroscopic portals. Guide wires w ere 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 structur es. Five additional knees were dissected free of all soft tissues exce pt the tibial insertions of the meniscal roots and anterior cruciate l igament/posterior cruciate ligament. Each tibia was mounted in a jig a nd 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 comput er program allowing for surface area determination and computer-genera ted topographical maps to assess relative position of each specific in sertion site, Placement of the arthroscope in the anterolateral portal allows optimal visualization and guide wire placement for both latera l meniscal horn insertion sites. Medial meniscal anterior and posterio r horn insertion sites are best visualized with the arthroscope in the anteromedial and posteromedial portals respectively. Each meniscal ho rn was found to have an anatomically distinct bony insertion site with characteristic acid consistent landmarks defining its margins. The an terior horn of the medial meniscus has the largest insertion, two time s greater than that of the posterior horn of the lateral meniscus. Sta tistical analysis showed medial horn insertion sites to be greater tha n lateral insertions and for the medial meniscus, anterior horn insert ion sites larger than posterior horn insertion sites (P < .05). Wherea s the ''footprint'' of the anterior horn insertions are relatively pla nar, the posterior horn insertions are significantly more complex in t hree dimension. In conclusion, we have provided data on the relative s izes, shapes, and locations of the human meniscal bony insertion sites -a critical prerequisite needed before performing meniscal reconstruct ion.