Trochlear facet asymmetry
Updates to Article Attributes
Trochlear facet asymmetry (FA) in refers to the condition of the medial facet being abnormally small if compared to the lateral facet in trochlear dysplasia 1.
Usage
Facet asymmetry (FA) is also used as a measurement in magnet resonance imaging for trochlear dysplasia to make it more objective 1-3, this concept was adapted from axial radiographs 3.
Measurement
One option to measure facet asymmetry is the ratio between medial versus lateral trochlear facet length calculated as (medial facet) / (lateral facet) 1. Another option is to calculate it the other way around, that is (lateral facet) / (medial facet) 2.
Facet asymmetry traditionally measured 3cm above the joint line 1,3.
Interpretation
A threshold of < 0.4 or 40% was suggestive of trochlear dysplasia and showed a sensitivity and specificity of 100% and 96% in that study 2.
History and etymology
The principle has been adapted for magnetic resonance imaging by Pfirrmann 1.
See also
-<p><strong><strong>Trochlear facet asymmetry (FA)</strong></strong> in refers to the condition of the medial facet being abnormally small if compared to the lateral facet in trochlear dysplasia <sup>1</sup>.</p><h4>Usage</h4><p>Facet asymmetry (FA) is also used as a measurement in magnet resonance imaging for <a href="/articles/trochlear-dysplasia">trochlear dysplasia</a> to make it more objective <sup>1-3</sup>, this concept was adapted from axial radiographs <sup>3</sup>.</p><h4>Measurement</h4><p>One option to measure facet asymmetry is the ratio between medial versus lateral trochlear facet length calculated as (medial facet) / (lateral facet) <sup> 1</sup>. Another option is to calculate it the other way around, that is (lateral facet) / (medial facet) <sup>2</sup>.</p><p>Facet asymmetry traditionally measured 3cm above the joint line <sup>1,3</sup>. <sup> </sup></p><h4>Interpretation</h4><p>A threshold of < 0.4 or 40% was suggestive of trochlear dysplasia and showed a sensitivity and specificity of 100% and 96% in that study <sup>2</sup>.</p><h4>History and etymology</h4><p>The principle has been adapted for magnetic resonance imaging by Pfirrmann <sup>1</sup>.</p><h4>See also</h4><ul>- +<p><strong><strong>Trochlear facet asymmetry (FA)</strong></strong> refers to the condition of the medial facet being abnormally small if compared to the lateral facet in trochlear dysplasia <sup>1</sup>.</p><h4>Usage</h4><p>Facet asymmetry (FA) is also used as a measurement in magnet resonance imaging for <a href="/articles/trochlear-dysplasia">trochlear dysplasia</a> to make it more objective <sup>1-3</sup>, this concept was adapted from axial radiographs <sup>3</sup>.</p><h4>Measurement</h4><p>One option to measure facet asymmetry is the ratio between medial versus lateral trochlear facet length calculated as (medial facet) / (lateral facet) <sup> 1</sup>. Another option is to calculate it the other way around, that is (lateral facet) / (medial facet) <sup>2</sup>.</p><p>Facet asymmetry traditionally measured 3cm above the joint line <sup>1,3</sup>. <sup> </sup></p><h4>Interpretation</h4><p>A threshold of < 0.4 or 40% was suggestive of trochlear dysplasia and showed a sensitivity and specificity of 100% and 96% in that study <sup>2</sup>.</p><h4>History and etymology</h4><p>The principle has been adapted for magnetic resonance imaging by Pfirrmann <sup>1</sup>.</p><h4>See also</h4><ul>
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