Osteonecrosis of the femoral head
Updates to Article Attributes
Body
was changed:
The hip is one of the most frequent sites for avascular necrosis, presumably due to a combination of precarious blood supply and high loading when standing. It can be thought of as traumatic (secondary to neck of femur fractures) or non-traumatic. In non-traumatic cases it is bilateral in 40%.
Typically it affects the superior articular surface (between 10-2 Oo'clock) and begins in the more anterior part of the hip.
Pathology
Aetiology
- traumatic
- chronic corticosteroid therapy
- alcoholism
- smoking
- SLE
- hyperlipidemias
- HIV
- haemoglobinopathies
- chronic renal failure
- diabetes
Clinical presentation
The most common presenting symptom is pain in the region of affected hip, thigh, groin and buttock. Although few patients may remain asymptomatic until late stages.
Radiographic features
Specific staging system (Ficat staging) exists for the hip which includes X-ray, MRI and bone scan appearance, and covers much of the imaging appearances, thus please refer to that article.
Other than describing the general appearance of the affect region the following are important to include in the report as they have and effect on prognosis and treatment:
- position
- estimating
%percentage volume of the head involved (axial) and% wtpercentage weight bearing surface involved (coronal) - coexisting osteoarthritis
/or secondary degenerative change - joint effusion
- presence of a potentially unstable osteochondral fragment: rim sign
MRI
MRI is the most sensitive modality, with sensitivity of 71-100% and specificity of 94-100%1. As there is a high rate of bilateral involvement both hips should be included in the field of view of at least some sequences.
-
T1:
:usually the initial specific findings are areas of low intensities represent oedema, which can be bordered by a hyper-intense line which represents blood products -
T2:
:it may show a second hyper-intense inner line between normal marrow and ischaemic marrow. This appearance is highly specific for AVN hip and known as "double line sign"
Differential diagnosis
General imaging differential considerations include
- haematopoetic marrow (see bone marrow)
- Pitt's pit
- fovea centralis
- idiopathic transient osteoporosis of the hip (ITOH)
- chondroblastoma
- metastases
See also
-<p>The <strong>hip</strong> is one of the most frequent sites for <a href="/articles/avascular-necrosis">avascular necrosis</a>, presumably due to combination of precarious blood supply and high loading when standing. It can be thought of as traumatic (secondary to <a href="/articles/proximal_femoral_fracture">neck of femur fractures</a>) or non-traumatic. In non-traumatic cases it is bilateral in 40%.</p><p>Typically it affects the superior articular surface (between 10-2 O'clock) and begins in the more anterior part of the hip.</p><h4>Pathology</h4><h5>Aetiology</h5><ul>-<li>traumatic</li>-<li>chronic corticosteroid therapy</li>-<li>alcoholism</li>-<li>smoking</li>-<li>SLE</li>-<li>hyperlipidemias</li>-<li>HIV</li>-<li>haemoglobinopathies</li>-<li>chronic renal failure</li>-<li>diabetes</li>-</ul><h4>Clinical presentation</h4><p>The most common presenting symptom is pain in the region of affected hip, thigh, groin and buttock. Although few patients may remain asymptomatic until late stages.</p><h4>Radiographic features</h4><p>Specific staging system (<a href="/articles/avascular-necrosis-of-the-hip-classification">Ficat staging</a>) exists for the hip which includes X-ray, MRI and bone scan appearance, and covers much of the imaging appearances, thus please refer to that article. </p><p>Other than describing the general appearance of the affect region the following are important to include in the report as they have and effect on prognosis and treatment:</p><ul>-<li>position </li>-<li>estimating % volume of the head involved (axial) and % wt bearing surface involved (coronal)</li>-<li>coexisting <a href="/articles/osteoarthritis">osteoarthritis</a> / secondary degenerative change</li>-<li>joint effusion</li>-<li>presence of a potentially unstable osteochondral fragment : <a href="/articles/rim-sign-of-avn-1">rim sign</a>-</li>-</ul><h5>MRI</h5><p>MRI is the most sensitive modality, with sensitivity of 71-100% and specificity of 94-100%<sup>1</sup>. As there is a high rate of bilateral involvement both hips should be included in the field of view of at least some sequences.</p><ul>-<li>-<strong>T1</strong>: usually the initial specific findings are areas of low intensities represent oedema, which can be bordered by a hyper-intense line which represents blood products</li>-<li>-<strong>T2</strong>: it may show a second hyper-intense inner line between normal marrow and ischaemic marrow. This appearance is highly specific for AVN hip and known as "double line sign" </li>-</ul><h4>Differential diagnosis</h4><p>General imaging differential considerations include</p><ul>-<li>haematopoetic marrow (see <a href="/articles/bone-marrow">bone marrow</a>)</li>-<li><a href="/articles/pitts-pit">Pitt's pit</a></li>-<li><a href="/articles/fovea-centralis">fovea centralis</a></li>-<li><a href="/articles/idiopathic-transient-osteoporosis-of-the-hip">idiopathic transient osteoporosis of the hip (ITOH)</a></li>-<li><a href="/articles/chondroblastoma">chondroblastoma</a></li>-<li>metastases</li>- +<p>The <strong>hip</strong> is one of the most frequent sites for <strong><a href="/articles/avascular-necrosis">avascular necrosis</a></strong>, presumably due to a combination of precarious blood supply and high loading when standing. It can be thought of as traumatic (secondary to <a href="/articles/proximal_femoral_fracture">neck of femur fractures</a>) or non-traumatic. In non-traumatic cases it is bilateral in 40%.</p><p>Typically it affects the superior articular surface (between 10-2 o'clock) and begins in the more anterior part of the hip.</p><h4>Pathology</h4><h5>Aetiology</h5><ul>
- +<li>traumatic</li>
- +<li>chronic corticosteroid therapy</li>
- +<li>alcoholism</li>
- +<li>smoking</li>
- +<li>SLE</li>
- +<li>hyperlipidemias</li>
- +<li>HIV</li>
- +<li>haemoglobinopathies</li>
- +<li>chronic renal failure</li>
- +<li>diabetes</li>
- +</ul><h4>Clinical presentation</h4><p>The most common presenting symptom is pain in the region of affected hip, thigh, groin and buttock. Although few patients may remain asymptomatic until late stages.</p><h4>Radiographic features</h4><p>Specific staging system (<a href="/articles/avascular-necrosis-of-the-hip-classification">Ficat staging</a>) exists for the hip which includes X-ray, MRI and bone scan appearance, and covers much of the imaging appearances, thus please refer to that article. </p><p>Other than describing the general appearance of the affect region the following are important to include in the report as they have and effect on prognosis and treatment:</p><ul>
- +<li>position </li>
- +<li>estimating percentage volume of the head involved (axial) and percentage weight bearing surface involved (coronal)</li>
- +<li>coexisting <a href="/articles/osteoarthritis">osteoarthritis</a> or secondary degenerative change</li>
- +<li>joint effusion</li>
- +<li>presence of a potentially unstable osteochondral fragment: <a href="/articles/rim-sign-of-avn-1">rim sign</a>
- +</li>
- +</ul><h5>MRI</h5><p>MRI is the most sensitive modality, with sensitivity of 71-100% and specificity of 94-100%<sup>1</sup>. As there is a high rate of bilateral involvement both hips should be included in the field of view of at least some sequences.</p><ul>
- +<li>
- +<strong>T1:</strong> usually the initial specific findings are areas of low intensities represent oedema, which can be bordered by a hyper-intense line which represents blood products</li>
- +<li>
- +<strong>T2:</strong> it may show a second hyper-intense inner line between normal marrow and ischaemic marrow. This appearance is highly specific for AVN hip and known as "double line sign" </li>
- +</ul><h4>Differential diagnosis</h4><p>General imaging differential considerations include</p><ul>
- +<li>haematopoetic marrow (see <a href="/articles/bone-marrow">bone marrow</a>)</li>
- +<li><a href="/articles/pitts-pit">Pitt's pit</a></li>
- +<li><a href="/articles/fovea-centralis">fovea centralis</a></li>
- +<li><a href="/articles/idiopathic-transient-osteoporosis-of-the-hip">idiopathic transient osteoporosis of the hip (ITOH)</a></li>
- +<li><a href="/articles/chondroblastoma">chondroblastoma</a></li>
- +<li>metastases</li>
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