MRI of acute meniscal injury associated with tibial plateau fractures: prevalence, type, and location.

OBJECTIVE: The purpose of this study was to evaluate the prevalence, type, and location of meniscal injuries, particularly to assess the prevalence of unstable meniscal tears in acute knee trauma with tibial plateau fractures.
MATERIALS AND METHODS: A total of 78 menisci were evaluated in 39 patients who had undergone knee MDCT and MRI. Meniscal tears were classified as horizontal, vertical (subdivided into longitudinal and radial), flap, bucket-handle, or complex. The presence of meniscal contusion was documented. The anterior horn, body, and posterior horn were assessed separately for both menisci. Knee arthroscopy was performed on 28 patients.
RESULTS: Of the 39 patients in the study, 24 had detectable abnormal menisci, for a total of 33 abnormal menisci (42%). Among the 33 meniscal abnormalities were 11 longitudinal tears (33%), 17 contusions (52%), four flap tears (12%), six horizontal tears (18%), and six radial tears (18%). Among the 16 patients with meniscal tears (41% of the 39), 14 patients had an unstable tear. No significant correlation was found between degree of articular depression and site or morphologic features of the meniscal injury. Correspondingly, no statistical correlation was evident between normal menisci and degree of articular depression, nor was a significant correlation found between differing fracture groups and meniscal findings.
CONCLUSION: A high percentage of patients (36%) with a tibial plateau fracture had an unstable meniscal tear. If a meniscal tear is detected preoperatively, meniscal surgery can be combined with fracture fixation, and reoperation can be avoided. A large number of meniscal contusions were found. Awareness of this abnormality can help radiologists increase specificity by avoiding false-positive findings of meniscal tear.