To quantitatively evaluate the position, size, and shape of the menisci in subjects with radiographic knee osteoarthritis (OA) compared to subjects without OA, using magnetic resonance imaging (MRI). Methods
We studied the right knees of 39 Osteoarthritis Initiative participants (24 women and 15 men with a mean age of 59.6 +/- 8.7 years) with medial compartment radiographic tibiofemoral OA (Kellgren/Lawrence grade of 2 or 3). Subjects were matched individually for age, sex, and height to controls without knee OA and without risk factors for knee OA. The right knees of the controls were used as references. One observer performed manual segmentation of the tibial plateau and the medial and lateral meniscus based on a coronally reconstructed double-echo steady-state sequence with water excitation, focusing on 5 central 3T MRIs. ResultsIn OA knees, there was less meniscal coverage of the medial tibial plateau (435 mm(2) versus 515 mm(2); P = 0.0004), the medial meniscus body showed more extrusion (2.64 mm versus 0.53 mm; P < 0.0001), and the peripheral margin had a more convex shape, i.e., bulged more (mean 0.61 mm versus 0.27 mm; P < 0.0001). The thickness or volume of the medial meniscus body of OA knees did not differ substantially from reference knees. In contrast, in OA knees the lateral meniscus body had a larger volume (mean 266 mm(3) versus 224 mm(3); P = 0.0005) and extruded more (mean 1.16 mm versus -1.01 mm; P < 0.0001), and the external margin bulged more (mean 0.53 mm versus 0.35 mm; P < 0.0001), than in reference knees. Conclusion
Our findings indicate altered meniscal position and shape (i.e., more bulging) in both compartments in medial compartment knee OA. These changes may be important features of OA pathogenesis and/or disease consequences.
"The tendency in the present study to increased extrusion of the medial meniscus body with time, not affecting coverage and overlap distance to the same extent, might potentially indicate increased bulging of the peripheral meniscal margin (more convex shape), i.e., not so much radial displacement (shift in position). Of note, meniscal extrusion is a combined construct of radial displacement and potential change in meniscus width, e.g., due to bulging of the peripheral meniscus margin and/or meniscus hypertrophy [32,33]. The clinical relevance of our longitudinal findings is unknown, and is a question for forthcoming studies. "
[Show abstract][Hide abstract] ABSTRACT: A high degree of meniscal body extrusion on knee magnetic resonance imaging has been shown to be strongly associated with development of knee osteoarthritis However, very little is known about meniscal position in the asymptomatic knee and its natural history. Hence our objective was to study meniscal body position and its change over 4 years in asymptomatic adults.
Cohort study using data from the Osteoarthritis Initiative (OAI) involving four clinical sites in United States (Baltimore, Maryland, Pawtucket, Rhode Island, Columbus, Ohio, and Pittsburgh, Pennsylvania). We studied both knees from 118 subjects (mean age 55 years, 61% women, mean body mass index 24.4) from the OAI "non-exposed" reference cohort free of knee pain, radiographic knee osteoarthritis and risk factors for knee osteoarthritis at baseline. We assessed mid-coronal intermediate-weighted 3-Tesla magnetic resonance images from baseline and the 2- and 4-year follow-up visit. One observer measured tibia plateau, meniscal body width and meniscal body extrusion in both compartments. We calculated meniscal overlap distance on the tibial plateau,% coverage, and extrusion index compared to tibia width. Potential trends in position over the 4-year period were evaluated using a linear mixed-effects regression model.
The mean (SD) values at baseline for medial meniscal body extrusion and overlap distance were 1.64 mm (0.92) and 10.1 mm (3.5), and coverage was 34.4% (11.9). The corresponding values for the lateral compartment were 0.63 mm (0.73), 9.8 mm (2.4), and 31.0% (7.7). Medial meniscus body extrusion index was greater in female knees (p = 0.03). There was slight increase in medial meniscal body extrusion over 4 years (0.040 mm/year [95% CI: 0.019-0.062]). The other variables were relatively stable.
In asymptomatic adults, the relative degree of meniscus body extrusion is more pronounced in female knees. Although a slight increase in extrusion over time was noted for the medial body, positions were relatively stable within subjects over time.
[Show abstract][Hide abstract] ABSTRACT: Magnetic resonance imaging (MRI) has become an increasingly important imaging technique in osteoarthritis (OA) research, and is widely used in the ongoing endeavor to understand the pathogenesis of OA and to develop structure and disease-modifying OA drugs. MRI offers semiquantitative, quantitative and compositional evaluation of knee OA, and enables visualization of tissues that are not seen by radiography, including but not limited to cartilage, meniscus, bone marrow lesions, synovitis, and muscles. It is now recognized that contrast-enhanced MRI enables more accurate evaluation of synovitis than MRI without contrast. Because of its ability to visualize multiple pain-related tissue pathology in three dimensions, MRI is the best modality for imaging of OA.
Current Rheumatology Reports 01/2014; 16(1):391. DOI:10.1007/s11926-013-0391-6 · 2.87 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Osteoarthritis (OA) is the most prevalent joint disorder with no approved disease-modifying treatment available. The importance of imaging in assessing all joint structures involved in the disease process, including articular cartilage, meniscus, subarticular bone marrow, and synovium for diagnosis, prognostication, and follow-up, has been well recognized. In daily clinical practice, conventional radiography is still the most commonly used imaging technique for the evaluation of a patient with known or suspected OA and radiographic outcome measures are still the only approved end point by regulatory authorities in clinical trials. The ability of magnetic resonance imaging (MRI) to visualize all joint structures in three-dimensional fashion including tissue ultrastructure has markedly deepened our understanding of the natural history of the disease. This article describes the roles and limitations of different imaging modalities for clinical practice and research in OA, with a focus on radiography and MRI and an emphasis on the knee joint.
Best practice & research. Clinical rheumatology 02/2014; 28(1):31-60. DOI:10.1016/j.berh.2014.02.002 · 2.60 Impact Factor
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