J Korean Soc Magn Reson Med.  2014 Sep;18(3):219-224. 10.13104/jksmrm.2014.18.3.219.

Pseudoradial Tear of the Medial Meniscus: A Relatively Common Potential Pitfall

• You WY
• Choi JA
• Oh KJ
• Min SJ
• Choi JJ
• Chang SK
• Hwang DH
• Kang IW

• KMID: 1999921
• DOI: http://doi.org/10.13104/jksmrm.2014.18.3.219

Abstract

PURPOSE
To determine the incidence of truncated triangle appearance of anterior horn (AH) to body of medial meniscus (MM) and determine its clinical significance.
MATERIALS AND METHODS
IRB approval was obtained, and informed consent waived for this study. The criteria of "pseudoradial tear" was truncated triangle appearance of the tip of AH to body of MM on one or more coronal images with adjacent fluid signal intensity at the blunted tip. Two musculoskeletal radiologists retrospectively evaluated 485 knee MR images independently for the presence and number of sections with "pseudoradial tear" of AH to body of MM using proton density-weighted coronal MR images. Inter-and intraobserver agreement was calculated using kappa coefficients. Medical records were reviewed for arthroscopic correlation.
RESULTS
A pseudoradial tear in the AH to body of MM was present in 381 (78.6%) patients. Locations were 112 in AH (29.4%), 143 in AH to body (37.5%), and 126 in body (33.1%). Number of consecutive sections of pseudoradial tear were 1 in 100 (26.2%), 2 in 164 (43.0%), 3 in 94 (24.7%), 4 in 21 (5.5%), and 5 in 2 (0.5%). Interobserver agreement was 0.99 for presence and 0.43 for number of sections of pseudoradial tear. Arthroscopies were performed in 96 patients and none of the pseudoradial tears were proven as true radial tears on arthroscopy.
CONCLUSION
Pseudoradial tears are frequently seen in AH to body of MM on coronal MR images and may be another pitfall that a radiologist needs to be aware of and be able to differentiate from true radial tear.

Keyword

Knee; Meniscus; Magnetic resonance imaging

MeSH Terms

Animals
Arthroscopy
Ethics Committees, Research
Horns
Humans
Incidence
Informed Consent
Knee
Magnetic Resonance Imaging
Medical Records
Menisci, Tibial*
Protons
Retrospective Studies
Tears*
Protons

Figure

• 

  Fig. 1 Pseudoradial tear at the junction of anterior horn to body of the medial meniscus in a 11-year-old girl on proton densityweighted spectral presaturation inversion recovery (SPIR) coronal image (TR/TE, 2718/7.617; 3-mm section thickness) shown as blunting of the tip of the medial meniscus (arrow). Meniscus was intact at arthroscopy.

• 

  Fig. 2 Pseudoradial tear at the junction of anterior horn to body of the medial meniscus in a 39-year-old women on proton density-weighted coronal image (TR/TE, 2651/12; 4-mm section thickness) shows adjacent fluid signal intensity at the blunted tip of the medial meniscus (arrow). Meniscus was intact at arthroscopy.

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