MRI study of the transverse ligament of knee, anterior and posterior meniscofemoral ligament and the application in the diagnosis of " pseudotears sign" of lateral meniscus

Abstract

Objective To investigate the anatomic features of the MRI of the transverse ligament of knee(TLK) , anterior meniscofemoral ligament(aMFL) and posterior meniscofemoral ligament(pMFL) of the knee, and the value of identifying the true and false tear of the lateral meniscus of the knee joint. Methods One hundred and one patients with knee joint surgery in the Department of Orthopedics of the Third Affiliated Hospital of Guangxi Medical University from August 2014 to August 2015 were retrospectively analyzed, and all of patients with meniscus true tear were excluded. There were 60 males and 41 females with an average age of 42 (18-75) years. Multiple sequence and plane of MR scan were performed to observe the display rates of the TLK, aMFL and pMFL, the mid-point, the way of walking and the appearance of pseudo-tears sign of them. Chi square test was used on the gender and sides of the pseudo-tears sign rate. Results The TLK was presented in 67.3%(68/101), the cross section more presentation oval-like and circular-like, the average of the mid-point of the sagittal diameter was (1.88±0.35)mm, coronary diameter was (1.79±0.60)mm, the pseudo-tears sign displayed in the anterior horn of the lateral meniscus was presented in 2.9%(2/68). The aMFL and pMFL was presented in 13.9%(14/101) and 77.2%(78/101), respectively, the cross section of the aMFL were oval-like, flat-like and irregular-like, the average of the mid-point of the aMFL of the sagittal diameter was (1.53±0.39)mm, coronary diameter was (2.8±0.92)mm, the average of the mid-point of pMFL of the sagittal diameter was (2.0±1.03)mm, coronary diameter was (3.10±1.08)mm, the pseudo-tears sign displayed in the posterior horn of the lateral meniscus was presented in 18.5%(17/92). There was no significant difference in the pseudo-tears sign of the lateral meniscus in different genders and sides(all P values﹥0.05). Conclusions In the MRI examination of the knee joint, pseudo-tears sign is sometimes displayed in the lateral meniscus, and these three ligaments studied in this way can improve the recognition of them, based on the anatomy and position of these ligaments, and the direction and location of pseudo-tears, the pseudo-tears can be distinguished from the true tear of posterior horn of the lateral meniscus so as to reduce the unnecessary surgical treatment. Key words: Knee joint; Menisci, tibial; Magnetic resonance imaging; Transverse ligament of knee; Anterior meniscofemoral ligament; Posterior meniscofemoral ligament; Pseudo-tears sign