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MR imaging of tears of discoid lateral menisci
1Department of Diagnostic Radiology, College of Medicine, Kyung Hee University, Seoul, Korea.
Objective:
The purpose of this study was to determine the positive predictive value (PPV) for diagnosis of discoid lateral meniscal tear using MR imaging and to describe various patterns of such tears in the knee.
Subjects And Methods:
MR reports of 77 patients (10-67 years old) who underwent prospective MR imaging that led to a diagnosis of discoid lateral meniscal tear were correlated with arthroscopic results. MR images obtained in 71 patients confirmed to have discoid lateral meniscial tear were retrospectively reviewed for the presence, site, and pattern of discoid lateral meniscal tear, including type of displacement of the torn segment. MR abnormalities were correlated with arthroscopic findings.
Results:
For the prospective MR interpretations, the PPV for discoid meniscus was 92%. PPV for discoid meniscal tear was 57%. PPVs for individual types of discoid meniscal tears were 46% (peripheral tear, 19/41), 76% (peripheral tear with horizontal tears, 16/21), 56% (horizontal tear, 5/9), 50% (transverse tear, 1/2), 67% (horizontal tear combined with transverse tear, 2/3), and 100% (longitudinal tear, 1/1). Peripheral tear alone and peripheral tear with horizontal tear were the most common types of tears (n = 20, 28%). Multiple tears (n = 34, 48%) were common. Displacement of the torn segments was seen in 51 patients (72%).
Conclusion:
MR imaging has a low PPV for diagnosing discoid lateral meniscal tear. Peripheral tear alone and peripheral tear with horizontal tear were the most common types of tears, and displacement of the torn segment was frequent.
Insights
Magnetic Resonance (MR) imaging has a limited positive predictive value (PPV) for diagnosing discoid lateral meniscal tears. Peripheral tears with or without horizontal components were most frequent, often with displaced segments.
Area of Science:
- Orthopedics
- Radiology
- Sports Medicine
Background:
- Discoid lateral meniscus is a congenital anomaly.
- Tears of the discoid lateral meniscus can cause knee pain and mechanical symptoms.
- Accurate diagnosis is crucial for appropriate management.
Purpose of the Study:
- To determine the positive predictive value (PPV) of MR imaging for diagnosing discoid lateral meniscal tears.
- To characterize the various patterns and locations of these tears.
Main Methods:
- Retrospective review of MR images from 71 patients with confirmed discoid lateral meniscal tears.
- Correlation of MR findings with arthroscopic results.
- Analysis of tear presence, site, pattern, and displacement.
Main Results:
- The PPV for discoid meniscus diagnosis was 92%, but for discoid meniscal tear, it was 57%.
- Peripheral tears (alone or with horizontal components) were most common (47%).
- Tear displacement occurred in 72% of cases, and multiple tears were frequent (48%).
Conclusions:
- MR imaging demonstrates a low PPV for discoid lateral meniscal tears.
- Peripheral tears and peripheral tears with horizontal components are the most prevalent tear types.
- Displacement of torn meniscal segments is a common finding.