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Posterior medial meniscus root ligament lesions: MRI classification and associated findings
Ja-Young Choi1, Eric Y Chang, Guilherme M Cunha
11 Department of Radiology, Seoul National University Hospital, Seoul, Korea.
Objective:
The purposes of this study were to determine the prevalence of altered MRI appearances of "posterior medial meniscus root ligament (PMMRL)" lesions, introduce a classification of lesion types, and report associated findings.
Materials And Methods:
We retrospectively reviewed 419 knee MRI studies to identify the presence of PMMRL lesions. Classification was established on the basis of lesions encountered. The medial compartment was assessed for medial meniscal tears in the meniscus proper, medial meniscal extrusion, insertional PMMRL osseous changes, regional synovitis, osteoarthritis, insufficiency fracture, and cruciate ligament abnormality.
Results:
PMMRL abnormalities occurred in 28.6% (120/419) of the studies: degeneration, 14.3% (60/419) and tear, 14.3% (60/419). Our classification system included degeneration and tearing. Tearing was categorized as partial or complete with delineation of the point of failure as entheseal, midsubstance, or junction to meniscus. Of all tears, 93.3% (56/60) occurred at the meniscal junction. Univariate analysis revealed significant differences between the knees with and without PMMRL lesions in age, medial meniscal tear, medial meniscal extrusion, insertional PMMRL osseous change, regional synovitis, osteoarthritis, insufficiency fracture (p=0.017), and cruciate ligament degeneration (p<0.001).
Conclusion:
PMMRL lesions are commonly detected in symptomatic patients. We have introduced an MRI classification system. PMMRL lesions are significantly associated with age, medial meniscal tears, medial meniscal extrusion, insertional PMMRL osseous change, regional synovitis, osteoarthritis, insufficiency fracture, and cruciate ligament degeneration.
Insights
Posterior medial meniscus root ligament (PMMRL) lesions are common in symptomatic knees, with degeneration and tearing observed. These PMMRL lesions are significantly associated with various knee abnormalities and patient age.
Area of Science:
- Orthopedic imaging
- Knee MRI analysis
- Meniscal pathology
Background:
- The posterior medial meniscus root ligament (PMMRL) is crucial for knee stability.
- Altered MRI appearances of PMMRL lesions are increasingly recognized.
- A standardized classification for PMMRL lesions is needed.
Purpose of the Study:
- To determine the prevalence of altered MRI findings of PMMRL lesions.
- To introduce a classification system for PMMRL lesion types.
- To report associated knee abnormalities found with PMMRL lesions.
Main Methods:
- Retrospective review of 419 knee MRI studies.
- Identification and classification of PMMRL lesions based on observed types.
- Assessment of the medial compartment for associated pathologies including meniscal tears, extrusion, synovitis, osteoarthritis, and cruciate ligament abnormalities.
Main Results:
- PMMRL abnormalities were present in 28.6% of studies, with equal prevalence of degeneration and tearing (14.3% each).
- Tears predominantly occurred at the meniscal junction (93.3%).
- Significant associations were found between PMMRL lesions and increased age, medial meniscal tears, medial meniscal extrusion, osseous changes, synovitis, osteoarthritis, insufficiency fractures, and cruciate ligament degeneration.
Conclusions:
- PMMRL lesions are frequently detected in symptomatic patients via MRI.
- A novel MRI classification system for PMMRL lesions has been established.
- PMMRL lesions are significantly associated with multiple knee pathologies and patient age.
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