Date: Monday, November 9, 2015
Session Title: Orthopedics, Low Back Pain and Rehabilitation Poster
Session Type: ACR Poster Session B
Session Time: 9:00AM-11:00AM
Although the pathogenesis of spontaneous osteonecrosis of the knee (SONK) remains unclear, two main etiologies have been suggested in the pathogenesis of SONK: vascular and traumatic. Recently, the presence of medial meniscus tear has been proposed as a potential third etiology behind development of SONK. Meniscal extrusion is associated with the progression of osteoarthritis. However, there has been no information on correlation between meniscal extrusion and SONK. Our purpose was to determine whether the extent of meniscal extrusion is associated with the severity of SONK.
We examined 12 knees in 12 patients with a diagnosis of SONK in the medial femoral condyle between November 2010 and April 2015. All patients were examined by plain radiography and magnetic resonance imaging (MRI), which confirmed the diagnosis of SONK. No patient had a history of taking steroids or excessive alcohol consumption. There were four men and eight women, with a mean age of 70 years (55 to 82). The stage of progression of SONK was determined according to the radiological classification system. After measurement of anteroposterior, mediolateral, and superoinferior dimensions of the lesion by magnetic resonance imaging (MRI), its ellipsoid volume was calculated from the three dimensions. The extent of medial meniscus extrusion and its degeneration and tear were also evaluated by MRI.
The mean volume of the lesions in 12 patients with SONK was 2837 mm3 (324 to 7464). Degeneration and tear of the medial meniscus were found in 12 and 11 patients, respectively. The mean extrusion of the medial meniscus was 6.7 mm (3.0 to 10.2). Of the 12 knees with SONK, 2 knees showed the radiographic stage 2 lesions, 7 knees the stage 3, and 3 knees the stage 4. When the ellipsoid volume of SONK lesion was compared among stages, the volume tended to increase with the stage progression (P=0.062 by ANOVA). Medial meniscal extrusion was likely to increase with the stage progression, although no statistically significant difference was found (P=0.234 by ANOVA). The simple linear regression of the ellipsoid volume of SONK lesion on medial meniscal extrusion showed a significant correlation (R=0.761, P=0.004).
The extent of medial meniscal extrusion was significantly associated with the size of the lesion of SONK, which could determine the prognosis of the disease.
To cite this abstract in AMA style:Yasuda T, Masuda S, Miyazaki Y, Hayashi M, Yamawaki Y, Watanabe M, Takeuchi H, Ota S, Fujita S, Onishi E, Iwaki K, Yamamoto H. Medial Meniscus Extrusion and Spontaneous Osteonecrosis of the Knee [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/medial-meniscus-extrusion-and-spontaneous-osteonecrosis-of-the-knee/. Accessed July 8, 2020.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/medial-meniscus-extrusion-and-spontaneous-osteonecrosis-of-the-knee/