Qualitative and Quantitative Anatomic Analysis of the Posterior Root Attachments of the Medial and Lateral Menisci

Background: The clinical importance of the meniscal posterior root attachments has been recently reported by both biomechanical and clinical studies. Although several studies have been performed to evaluate surgical techniques, there have been few studies on the quantitative arthroscopically pertinent anatomy of the posterior meniscal root attachments. Hypothesis: The posterior root attachments of the medial and lateral menisci are consistent among specimens, and repeatable quantitative measurements using arthroscopically pertinent landmarks are achievable. Study Design: Descriptive laboratory study. Methods: Twelve nonpaired, fresh-frozen cadaveric knees were used. The positions of the posterior root attachments of the medial and lateral menisci were identified, and 3-dimensional measurements to arthroscopically pertinent landmarks were performed using a coordinate measuring system. Results: The direct distance (+/- standard error of the mean) between the medial tibial eminence apex and the medial meniscus posterior root attachment center was 11.5 (+/- 0.9) mm. When split into directional components along the knee's main axes, the medial meniscus posterior root attachment center was 9.6 (+/- 0.8) mm posterior and 0.7 (+/- 0.4) mm lateral along the bony surface from the medial tibial eminence apex. It was located 3.5 (+/- 0.4) mm lateral from the medial articular cartilage inflection point and directly 8.2 (+/- 0.7) mm from the nearest tibial attachment margin of the posterior cruciate ligament. The direct distance between the lateral tibial eminence apex and the lateral meniscus posterior root attachment center was 5.3 (+/- 0.3) mm. When it was split into directional components using the knee's main axes, the lateral meniscus posterior root attachment center was 4.2 (+/- 0.4) mm medial and 1.5 (+/- 0.7) mm posterior from the lateral tibial eminence apex. The lateral meniscus posterior root attachment center was located 4.3 (+/- 0.5) mm medial from the nearest articular cartilage margin and directly 12.7 (+/- 1.1) mm from the nearest margin of the tibial attachment of the posterior cruciate ligament. Conclusion: This quantitative study reproducibly identified the posterior root attachment centers of the medial and lateral menisci in relation to arthroscopically pertinent landmarks and guidelines.