The use of contralateral knee magnetic resonance imaging to predict meniscal size during meniscal allograft transplantation

Purpose: The purpose of this study was to determine the size of each meniscus and compare it with the contralateral limb using conventional knee magnetic resonance imaging (MRI) taken from previously uninjured, healthy, young volunteers. Methods: The knee joints of 60 healthy volunteers (aged 21 to 43 years, 30 men and 30 women) were enrolled in this study. Standard 3.0-T MRI in a controlled setting was used. By use of the mid-coronal images, the height and width of each medial and lateral meniscus were measured. By use of the mid-sagittal images, the height and width of the anterior and posterior horns of each meniscus was measured. The whole length spanning from the most anterior margin to the most posterior margin of each meniscus was also measured. Mean, standard deviation, and 95% confidence interval values were determined for each measurement. Results: There were 3 incomplete discoid lateral menisci (10%) in men and 2 incomplete discoid menisci (6.7%) in women. The study group with non-discoid knees comprised 27 men and 28 women. The power of this study ranged from 0.57 to 0.66. All values showed good reliability (intraclass correlation coefficient range, 0.887 to 0.974). There were no significant differences between right and left menisci (all P > .05). There were significant differences between genders. All parameters showed significant differences (P < .05) except the medial meniscus width (P = .221). Conclusions: In this small subset of patients, there were no differences between right and left meniscal measurements according to MRI. Therefore, when one is performing meniscal allograft transplantation, contralateral knee MRI may be useful to determine the required size. Identifying both the overall width and length of each meniscus is important when preparing an allograft. Clinical Relevance: Contralateral knee MRI may be used for more accurate meniscal size measurement in patients undergoing meniscal allograft transplantation.