<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>2183-1351</journal-id>
<journal-title><![CDATA[Acta Radiológica Portuguesa]]></journal-title>
<abbrev-journal-title><![CDATA[Acta Radiol Port]]></abbrev-journal-title>
<issn>2183-1351</issn>
<publisher>
<publisher-name><![CDATA[Sociedade Portuguesa de Radiologia e Medicina Nuclear]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S2183-13512026000100803</article-id>
<article-id pub-id-type="doi">10.25748/arp.43212</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Avulsion Fracture of the Lateral Patellofemoral Ligament: A Rare Case Report]]></article-title>
<article-title xml:lang="pt"><![CDATA[Fratura Avulsiva do Ligamento Patelofemoral Lateral: Um Caso Clínico Raro]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Martins]]></surname>
<given-names><![CDATA[Ricardo Silva]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Rodrigues]]></surname>
<given-names><![CDATA[Susana Lopes]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Martins]]></surname>
<given-names><![CDATA[Patrícia A.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Freixo]]></surname>
<given-names><![CDATA[Beatriz]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Fonseca]]></surname>
<given-names><![CDATA[Diogo]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Instituto Português de Oncologia Francisco Gentil Serviço de Imagiologia ]]></institution>
<addr-line><![CDATA[Porto ]]></addr-line>
<country>Portugal</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Unidade Local de Saúde Matosinhos Serviço de Ortopedia e Traumatologia ]]></institution>
<addr-line><![CDATA[Porto ]]></addr-line>
<country>Portugal</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Hospital Lusíadas Porto Serviço de Imagiologia ]]></institution>
<addr-line><![CDATA[Porto ]]></addr-line>
<country>Portugal</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>01</month>
<year>2026</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>01</month>
<year>2026</year>
</pub-date>
<volume>38</volume>
<numero>1</numero>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://scielo.pt/scielo.php?script=sci_arttext&amp;pid=S2183-13512026000100803&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.pt/scielo.php?script=sci_abstract&amp;pid=S2183-13512026000100803&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.pt/scielo.php?script=sci_pdf&amp;pid=S2183-13512026000100803&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract We present the case of an adolescent with anterior knee pain after a sprint, without history of knee trauma or surgery, diagnosed with a lateral patellofemoral retinaculum avulsion fracture. Signs of Osgood-Schlatter disease were also present. Radiography revealed a small calcific fragment adjacent to the lateral patellar border, while MRI confirmed lateral patellar bone marrow edema, retinacular thickening and periosteal avulsion. Additional findings included bone marrow edema of the medial femoral condyle, which is suggestive of a transient medial patellar dislocation, even though the patient didn&#8217;t recall any traumatic event. Avulsions at the lateral retinacular insertion are extremely rare, with most reports focusing on iatrogenic medial instability. Recognition of this entity is crucial, as its clinical overlap with other anterior knee pain causes can obscure diagnosis. The combination of radiography and MRI is essential to ensure accurate identification and appropriate management in the suspicion of patellar avulsion fractures in adolescents.]]></p></abstract>
<abstract abstract-type="short" xml:lang="pt"><p><![CDATA[Resumo Apresentamos o caso de um adolescente com dor anterior no joelho após uma corrida, sem antecedentes traumáticos ou cirúrgicos, diagnosticado com fratura avulsiva do retináculo patelofemoral lateral. Coexistiam sinais de doença de Osgood-Schlatter. As radiografias evidenciaram pequeno fragmento calcificado adjacente ao bordo lateral da rótula, enquanto a ressonância magnética demonstrou edema medular ósseo da vertente lateral da rótula, espessamento do retináculo e avulsão periosteal lateral. Identificou-se ainda edema medular do côndilo femoral medial, sugerindo luxação medial transitória da rótula, apesar de o doente não recordar nenhum evento traumático. As fraturas avulsivas na inserção do retináculo lateral são extremamente raras, sendo a maioria dos casos no contexto de instabilidade medial iatrogénica. O reconhecimento desta entidade é fundamental, uma vez que a sua sobreposição clínica com outras causas de dor anterior no joelho pode dificultar o diagnóstico. A combinação da radiografia e ressonância magnética é essencial para garantir a identificação precisa do diagnóstico e uma abordagem adequada na suspeita de lesões avulsivas da patela em adolescentes.]]></p></abstract>
<kwd-group>
<kwd lng="pt"><![CDATA[Rótula]]></kwd>
<kwd lng="pt"><![CDATA[Luxação da rótula]]></kwd>
<kwd lng="pt"><![CDATA[Fraturas por avulsão]]></kwd>
<kwd lng="pt"><![CDATA[Retináculo patelofemoral lateral]]></kwd>
<kwd lng="pt"><![CDATA[Ligamento patelofemoral lateral]]></kwd>
<kwd lng="pt"><![CDATA[Doença de Osgood-Schlatter.]]></kwd>
<kwd lng="en"><![CDATA[Patella]]></kwd>
<kwd lng="en"><![CDATA[Patellar dislocation]]></kwd>
<kwd lng="en"><![CDATA[Avulsion fractures]]></kwd>
<kwd lng="en"><![CDATA[Lateral patellofemoral retinaculum]]></kwd>
<kwd lng="en"><![CDATA[Lateral patellofemoral ligament]]></kwd>
<kwd lng="en"><![CDATA[Osgood-Schlatter disease.]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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