Bony landmark between the attachment of the medial meniscus posterior root and the posterior cruciate ligament: CT and MR imaging assessment

Objectives: (1) To reveal the prevalence of the bony recess (posterior dimple) and (2) to determine the position of the posterior dimple on the tibial plateau using three-dimensional computed tomography (3DCT). Materials and methods: In this study, a retrospective review of 112 patients was performed to identify the posterior dimple and to evaluate its position on 3DCT. Magnetic resonance images (MRIs) were also used to determine the positional relationship among the posterior cruciate ligament (PCL), medial meniscus posterior insertion (MMPI), and posterior dimple. Results: The posterior dimple was observed in 100 of 112 knees (89.3%) on 3DCT. The center of the posterior dimple was 13.6 ± 0.8 mm from the medial tibial eminence apex. MRI showed that the posterior dimple separated the tibial attachment of the PCL and MMPI. Conclusion: This is the first study to discuss the prevalence and position of the bony recess in the posterior intercondylar fossa.