Joint effusion
Updates to Article Attributes
This article is dedicated to the humble joint effusion, particularly the plain radiographic appearances.
A joint effusion is defined as an increased amount of fluid within the synovial compartment of a joint. There is normally only a small physiological amount of fluid. Abnormal fluid accumulation can result from inflammation, infection or trauma and may be an exudate, transduate, blood or fat.
Recognition of a joint effusion on plain radiographs can be difficult, particularly for the non-radiologist. Appreciation of the typical appearances and signs of joint effusions can assist diagnosis.
Knee
A knee joint effusion appears as well-defined rounded homeogeneous soft tissue density within the suprapatellasuprapatellar recess on a lateral radiograph. The effusion will displace the quadraceps tendon and patella anteriorly.
Lipohaemarthrosis is a particular type of effusion that occurs in the setting of intra-articular fracture where a fat-fluid level is seen due to marrow fat leaking into the joint via the fracture.
Elbow
The sail sign is the key to recognising an elbow joint effusion. On a lateral radiograph, an effusion causes displacement of the anterior and posterior fat pads surrounding the distal humerus. The triangular appearance of the displaced low density fat pad simmulates the appearance of a sail.
An elbow joint effusion in the setting of trauma is very often a sign of an occult fracture. In adults the occult fracture is most commonly of the radial head while in children a non-displaced supracondylar fracture should be suspected.
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Ankle
An ankle joint effusion is best seen as a teardrop-shaped soft tissue density displacing the anterior fat pad on a lateral film. Effusion within the posterior recess is usually less well defined.
-<p>This article is dedicated to the humble <strong>joint effusion</strong>, particularly the plain radiographic appearances. </p><p>A joint effusion is defined as an increased amount of fluid within the synovial compartment of a joint. There is normally only a small physiological amount of fluid. Abnormal fluid accumulation can result from inflammation, infection or trauma and may be an exudate, transduate, blood or fat. </p><p>Recognition of a joint effusion on plain radiographs can be difficult, particularly for the non-radiologist. Appreciation of the typical appearances and signs of joint effusions can assist diagnosis. </p><h5>Knee</h5><p>A knee joint effusion appears as well-defined rounded homeogeneous soft tissue density within the suprapatella recess on a lateral radiograph. The effusion will displace the quadraceps tendon and patella anteriorly. </p><p><a href="/articles/lipohaemarthrosis" title="Lipohaemarthrosis of the knee">Lipohaemarthrosis</a> is a particular type of effusion that occurs in the setting of intra-articular fracture where a fat-fluid level is seen due to marrow fat leaking into the joint via the fracture. </p><h5>Elbow</h5><p>The <a href="/articles/sail_sign" title="Sail sign">sail sign</a> is the key to recognising an <a href="/articles/elbow-joint-effusion" title="Elbow joint effusion">elbow joint effusion</a>. On a lateral radiograph, an effusion causes displacement of the anterior and posterior fat pads surrounding the distal humerus. The triangular appearance of the displaced low density fat pad simmulates the appearance of a sail. </p><p>An <a href="/articles/elbow-joint-effusion" title="Elbow joint effusion">elbow joint effusion</a> in the setting of trauma is very often a sign of an occult fracture. In adults the occult fracture is most commonly of the radial head while in children a non-displaced <a href="/articles/supracondylar-fracture" title="Supracondylar fracture">supracondylar fracture </a>should be suspected. </p><p>{{youtube:http://www.youtube.com/watch?v=k1UYfi9zdOg}}</p><h5>Ankle </h5><p>An ankle joint effusion is best seen as a teardrop-shaped soft tissue density displacing the anterior fat pad on a lateral film. Effusion within the posterior recess is usually less well defined.</p>- +<p>This article is dedicated to the humble <strong>joint effusion</strong>, particularly the plain radiographic appearances. </p><p>A joint effusion is defined as an increased amount of fluid within the synovial compartment of a joint. There is normally only a small physiological amount of fluid. Abnormal fluid accumulation can result from inflammation, infection or trauma and may be an exudate, transduate, blood or fat.</p><p>Recognition of a joint effusion on plain radiographs can be difficult, particularly for the non-radiologist. Appreciation of the typical appearances and signs of joint effusions can assist diagnosis.</p><h5>Knee</h5><p>A knee joint effusion appears as well-defined rounded homeogeneous soft tissue density within the suprapatellar recess on a lateral radiograph. The effusion will displace the quadraceps tendon and patella anteriorly. </p><p><a href="/articles/lipohaemarthrosis">Lipohaemarthrosis</a> is a particular type of effusion that occurs in the setting of intra-articular fracture where a fat-fluid level is seen due to marrow fat leaking into the joint via the fracture.</p><h5>Elbow</h5><p>The <a href="/articles/sail_sign">sail sign</a> is the key to recognising an <a href="/articles/elbow-joint-effusion">elbow joint effusion</a>. On a lateral radiograph, an effusion causes displacement of the anterior and posterior fat pads surrounding the distal humerus. The triangular appearance of the displaced low density fat pad simmulates the appearance of a sail.</p><p>An <a href="/articles/elbow-joint-effusion">elbow joint effusion</a> in the setting of trauma is very often a sign of an occult fracture. In adults the occult fracture is most commonly of the radial head while in children a non-displaced <a href="/articles/supracondylar-fracture">supracondylar fracture </a>should be suspected. </p><p>{{youtube:http://www.youtube.com/watch?v=k1UYfi9zdOg}}</p><h5>Ankle </h5><p>An ankle joint effusion is best seen as a teardrop-shaped soft tissue density displacing the anterior fat pad on a lateral film. Effusion within the posterior recess is usually less well defined.</p>
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Image 4 X-ray (Lateral) ( update )
Image 5 X-ray (Lateral) ( update )
Image 6 X-ray (Lateral) ( update )
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