Transverse geniculate ligament of the knee: appearance and frequency on plain radiographs

Abstract

The aims of the study were to determine the frequency of visualization of the normal transverse geniculate ligament (TGL) of the knee on lateral plain radiographs with magnetic resonance imaging (MRI) as a reference, and to determine features that make this ligament apparent on plain radiographs. 50 consecutive lateral plain radiographs and sagittal T1-weighted images of corresponding knees were evaluated prospectively. A TGL was considered visualized on plain radiographs when an opacity of soft-tissue density was apparent in the posterior part of the Hoffa's fat pad. The TGL was identified in 29 of the 50 (58%) sagittal MR images; a TGL was observed on the lateral plain radiographs of six patients (12%). Correlation with the MR images showed that, when visualized on plain radiographs, the ligament is at least 3 mm thick and completely surrounded by fat. Our study shows that the TGL is a normal variant that can be recognized frequently on lateral plain radiographs of the knee.

MR imaging of the anterior intermeniscal ligament: classification according to insertion sites

“…Several cadaveric and imaging studies of this ligament have been made and it has been shown to be of variable thickness when present [4,5,6,7,8,9]. In a recent cadaveric study, three distinct types of AIL were described with regard to its insertion on or near the anterior horns of the menisci [4].…”

“…The AIL can sometimes be depicted in a lateral knee radiograph when there is enough surrounding fat to create adequate contrast around it [7,8]; however, it is with MR imaging that the AIL can best be visualized non-invasively. When present, this ligament is usually seen easily in the anterior part of the knee joint as a lowintensity band in MR imaging examinations of the knee [8,9].…”

“…When present, this ligament is usually seen easily in the anterior part of the knee joint as a lowintensity band in MR imaging examinations of the knee [8,9]. There is a single MR imaging study reporting the frequency of AIL in 50 patients [8]; however, no MR imaging investigation to classify this structure with regard to its insertion sites has been reported. Moreover, arthroscopic verification of MR imaging findings regarding the AIL has not been previously reported.…”

The reference point to measure the anterior intermeniscal ligament's thickness: an MRI study

“…This structure is also called the transverse geniculate ligament, meniscomeniscal ligament, anterior transverse ligament, and intermeniscal ligament. There have been a few studies considering its properties on plain radiography and on magnetic resonance imaging (MRI) [5,6,8]. Watanabe et al [8] retrospectively reviewed sagittal MRI findings of 200 knees to determine the frequency with which normal ligamentous and tendinous structures mimic pathological changes within the knee.…”

“…They then confirmed this by MRI. Another study by the same authors [6] prospectively evaluated findings by lateral plain radiography and sagittal MRI in 50 consecutive knees and in the corresponding knees. They found that anterior intermeniscal ligament was visible in 12% of cases by plain radiography and 58% of cases by MRI.…”