Change of signal intensity in the displaced medial meniscus after its reduction on MRI.
OBJECTIVE
To compare magnetic resonance (MR) signal intensity in the medial meniscus at the time of displacement and after its reduction in patients with a displaced bucket-handle tear of the meniscus associated with anterior cruciate ligament (ACL) injury.


METHODS
Nine chronic ACL-deficient patients (3 male, 6 female, mean age 29 years) with locking due to a displaced fragment of the medial meniscus following a bucket-handle tear were involved in this study. In all patients, the following two-stage surgeries were planned as follows: first operation, arthroscopic reduction of the meniscus; second operation, meniscal repair and ACL reconstruction after immobilization for 1-2 weeks. Magnetic resonance imaging (MRI) evaluation using coronal T2*-weighted images was performed when the knee was locked and after the meniscus was reduced. Signal intensity before and after meniscal reduction was compared in the same patients.


RESULTS
In 8 of the 9 patients, the displaced fragment exhibited high signal intensity in 1 patient and mildly high in 7 patients. After its reduction, the signal intensity changed to low in all 8 patients.


CONCLUSIONS
A high-intensity signal in the displaced fragment of the medial meniscus may change to low after its reduction to its original position. Therefore, at the time of decision-making regarding meniscus repair for a displaced meniscus in a locked knee, surgeons should give priority to arthroscopic findings rather than to signal intensity on MRI.


METHODS
Diagnostic study, Level III.
Department of Orthopedic Sports Medicine, Hoshigaoka Kosei Nenkin Hospital, 4-8-1 Hoshigaoka Hirakata, Osaka, 573-8511, Japan. hamada-m@umin.ac.jp
Masayuki
M
Hamada
Tomohiro
T
Matsui
Kazutaka
K
Kinugasa
Kenji
K
Yoneda
Shuji
S
Horibe
Konsei
K
Shino
D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D001182:Arthroscopy; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery; D019651:Plastic Surgery Procedures; D000070600:Tibial Meniscus Injuries