Evaluation of the Peripheral Rim Instability of the Discoid Meniscus in Children by Using Weight-Bearing Magnetic Resonance Imaging

Objective The aim of the study was to assess the peripheral rim instability and the clinical value of discoid meniscus. Methods We retrospectively studied 79 magnetic resonance imaging (MRI) examinations of discoid meniscus from May 2017 to September 2019. The patient symptoms and physical findings were documented. The patients underwent “dedicated” 0.25 T supine and weight-bearing MRI examination. Finally, all patients underwent arthroscopy. Results Sound/clicking during motion ( P = 0.009) and limited extension ( P = 0.044) of subjective symptoms, clunk during motion ( P = 0.035), and flexion contracture ( P = 0.012) of physical findings were significant predictors of peripheral rim instability. The comparison of the weight-bearing MRI with the supine position MRI demonstrated that the disformed discoid meniscus was shifted significantly and that no shift was displaced centrally ( P = 0.001). A correlation between discoid meniscal displacement and the presence of peripheral rim instability in arthroscopy was noted ( P < 0.001) using weight-bearing MRI. Conclusions The clinical symptoms of the patients combined with weight-bearing MRI can determine peripheral rim instability optimally.