American Journal of Roentgenology, Vol 170, 57-61, Copyright © 1998 by American Roentgen Ray Society

ARTICLES

The absent bow tie sign in bucket-handle tears of the menisci in the knee

CA Helms, A Laorr and WD Cannon Jr
Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA.

OBJECTIVE: Bucket-handle tears of the menisci are one of the most frequently missed diagnoses in MR examinations of the knee. This article describes the "absent bow tie sign," which can be used to identify bucket-handle tears on routine MR examinations of the knee. MATERIALS AND METHODS: The arthroscopic surgical reports (n = 350) from a single orthopedic surgeon's practice during a 24-month period were examined for patients who had a diagnosis of bucket-handle tear and who underwent MR imaging before surgery (n = 32). The MR examinations were retrospectively evaluated for the presence of a bow tie sign. The bow tie sign was considered normal when two sagittal images showed the body segment (a bow tie appearance). The bow tie sign was considered abnormal, consistent with a bucket-handle tear, when only one or no body segment was seen (the absent bow tie sign). Coronal images were evaluated for a truncated meniscus. Also, each MR examination was scrutinized for a displaced fragment and a double posterior cruciate ligament (PCL) sign. RESULTS: Thirty-three bucket-handle tears were found at arthroscopy in 32 patients. One patient had tears of the medial and lateral menisci. The absent bow tie sign was seen in 32 of the 33 cases (sensitivity, 97%) and correlated with the medial or lateral meniscus that was reported torn at arthroscopy. The single false-negative result occurred in a patient with a nondisplaced bucket- handle tear. The findings in 31 contralateral normal menisci were all negative for an absent bow tie sign (specificity, 100%). A displaced fragment was found in 30 (94%) of 32 cases. The coronal images showed a truncated meniscus in 21 (64%) of 33 cases. A double PCL sign was seen in 10 (30%) of 33 cases. CONCLUSION: The absent bow tie sign is an easily applied finding that can be used with good sensitivity to diagnose bucket-handle tears of the menisci on MR imaging. This sign has a higher accuracy rate than other findings common with bucket- handle tears, such as displaced fragments, a truncated appearance of the meniscus on coronal images, and the double PCL sign.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				B. C. Vande Berg, J. Malghem, P. Poilvache, B. Maldague, and F. E. Lecouvet Meniscal Tears with Fragments Displaced in Notch and Recesses of Knee: MR Imaging with Arthroscopic Comparison Radiology, March 1, 2005; 234(3): 842 - 850. [Abstract] [Full Text] [PDF]

				M. A. Camacho The Double Posterior Cruciate Ligament Sign Radiology, November 1, 2004; 233(2): 503 - 504. [Full Text] [PDF]

				C. A. Helms The Meniscus: Recent Advances in MR Imaging of the Knee Am. J. Roentgenol., November 1, 2002; 179(5): 1115 - 1122. [Full Text] [PDF]

				D. R. McAllister and A. R. Motamedi Spontaneous Healing of a Bucket-Handle Lateral Meniscal Tear in an Anterior Cruciate Ligament-Deficient Knee: A Case Report Am. J. Sports Med., September 1, 2001; 29(5): 660 - 662. [Full Text] [PDF]

				K. A. Lieberman The Absent Bow Tie Sign Radiology, April 1, 2000; 215(1): 263 - 265. [Full Text]

				L. K. Lecas, C. A. Helms, F. J. Kosarek, and W. E. Garret Inferiorly Displaced Flap Tears of the Medial Meniscus: MR Appearance and Clinical Significance Am. J. Roentgenol., January 1, 2000; 174(1): 161 - 164. [Abstract] [Full Text] [PDF]