The Condylar Cutoff Sign: Quantifying Lateral Femoral Condylar Hypoplasia in a Complete Discoid Meniscus

Abstract

We describe the condylar cutoff sign, a radiographic sign in knees with a discoid lateral meniscus, for diagnosis of complete discoid meniscus. We retrospectively reviewed tunnel-view radiographs of 100 patients (100) knees including 50 with complete discoid lateral meniscus and 50 with normal menisci. All patients were 18 years of age or older. All of the knees were arthroscopically examined. We developed a method to measure the prominence of the femoral condyle adjacent to the intercondylar notch on a tunnel view of the knee. The prominence ratio, the ratio of the medial and lateral condylar prominence, was compared and analyzed. The measurements were performed by three observers on two separate occasions to determine reliability. The intraobserver and interobserver variability study revealed high reliability with correlation coefficients ranging from 0.86 to 0.99. Using a cutoff ratio of 0.8, we observed a major difference between the two groups and found the ratio had 76% sensitivity, 96% specificity, 95% positive predictive value, and 80% negative predictive value in every set of measurements. The sign has high specificity and reliability but might not apply to younger patients.

Characteristic morphology of the proximal tibiofibular joint in patients with discoid lateral meniscus

“…Numerous studies have outlined the morphological characteristics of DLM [7,[21][22][23][24][25] and, compared with a normal meniscus, patients with DLM have a higher frequency of meniscal tears [5,6]. In this study, we showed that most patients with DLM have a horizontal-type PTFJ.…”

Tibial eminence width can predict the presence of complete discoid lateral meniscus: A preliminary study

“…There has also been recent report of a significant difference in the condylar cut-off sign, which is a plain radiographic finding, between CDLM knees and normal knees [15]. However, the technique used in this report is not particularly convenient as the imaging method differs from normal frontal knee radiography.…”

Arthroscopic treatment of discoid lateral meniscus in children

“…Radiographs do not play a significant role in diagnosis [3], in our series we didn't see so called the condylar cutoff sign with the lateral space widening, hypoplasia of the lateral femoral condyle and the lateral tibial spine [10]. MRI can accurately show a discoid meniscus.…”

“…Zdjęcia rentgenowskie nie odgrywają istotnej roli w diagnostyce łąkotki tarczowatej [3], w naszej serii nie widzieliśmy poszerzenia przestrzeni przedziału bocznego kolana, ani niedorozwoju kłykcia bocznego kości udowej i wyniosłości międzykłykciowej kości piszczelowej [10]. Rezonans magnetyczny pozwala na najlepsze obrazowanie łąkotki tarczowatej, swoistość tego badania waha się pomiędzy 92-99% [3].…”