<?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>2306-4102</journal-id>
<journal-title><![CDATA[Acta ortopédica mexicana]]></journal-title>
<abbrev-journal-title><![CDATA[Acta ortop. mex]]></abbrev-journal-title>
<issn>2306-4102</issn>
<publisher>
<publisher-name><![CDATA[Colegio Mexicano de Ortopedia y Traumatología A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S2306-41022021000300257</article-id>
<article-id pub-id-type="doi">10.35366/102363</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Concordancia interobservador en la clasificación de Paprosky en un hospital de un país de una economía emergente]]></article-title>
<article-title xml:lang="en"><![CDATA[Inter-observer agreement in the Paprosky classification in a hospital in a country of an emerging economy]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Macedonio-García]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Rivera-Villa]]></surname>
<given-names><![CDATA[AH]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Quiroz-Williams]]></surname>
<given-names><![CDATA[J]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Aguilera-Martínez]]></surname>
<given-names><![CDATA[P]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Unidad Médica de Alta Especialidad «Dr. Victorio de la Fuente Narváez» Hospital de Ortopedia ]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>México</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Unidad Médica de Alta Especialidad «Dr. Victorio de la Fuente Narváez» Departamento Clínico de Reemplazos Articulares ]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>México</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Unidad Médica de Alta Especialidad «Dr. Victorio de la Fuente Narváez» Departamento de Investigación en Salud ]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>México</country>
</aff>
<aff id="Af4">
<institution><![CDATA[,Unidad Médica de Alta Especialidad «Dr. Victorio de la Fuente Narváez» Servicio de Reemplazos Articulares ]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>México</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2021</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2021</year>
</pub-date>
<volume>35</volume>
<numero>3</numero>
<fpage>257</fpage>
<lpage>260</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S2306-41022021000300257&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S2306-41022021000300257&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S2306-41022021000300257&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen:  Introducción:  La evaluación y manejo de la pérdida ósea acetabular en la artroplastía total de cadera es un desafío para los cirujanos ortopédicos, deseamos en este estudio determinar la concordancia interobservador en la clasificación de Paprosky para defectos acetabulares.  Material y métodos:  Estudio observacional, descriptivo, longitudinal, prospectivo. Se realizó utilizando las radiografías anteroposteriores de cadera de pacientes programados para artroplastía total de cadera primaria o de revisión con defecto óseo acetabular, sistema de rayos X local Sinapse, se valoraron 20 radiografías por observador tomadas de manera aleatoria (médicos adscritos al servicio de reemplazos articulares con experiencia mínima de cinco años) utilizando la clasificación de Paprosky de manera espontánea (sin clases previas) de defectos acetabulares, se evaluó la concordancia interobservador mediante el coeficiente de kappa de Cohen.  Resultados:  Se obtuvo una concordancia interobservador en promedio para la clasificación de Paprosky de defectos acetabulares utilizando el coeficiente de kappa de Cohen, el análisis de concordancia se hizo empleando el programa estadístico Statistical Package for the Social Sciences de 0.237.  Conclusiones:  Tanto la hipótesis nula (kappa mayor de 0.80 valor considerado óptimo) como la hipótesis alternativa (kappa de 0.41 a 0.80 valor igual a moderada a buena) no concordaron con nuestro estudio (kappa igual a 0.237) valor igual a leve, además se demostró que a mayor defecto acetabular menor es la concordancia interobservador en cirujanos en nuestra institución.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract:  Introduction:  The evaluation and management of acetabular bone loss in total hip arthroplasty is a challenge for orthopedic surgeons, we wish in this study to determine the inter-observer concordance in the Paprosky classification for acetabular defects.  Material and methods:  Observational, descriptive, longitudinal, prospective study. It was performed using anteroposterior hip radiographs of patients scheduled for primary total hip arthroplasty or revision with acetabular bone defect, Sinapse local X-ray system, 20 X-rays were assessed per observer taken randomly (doctors assigned to the joint replacement service with minimum experience of five years) using the Paprosky classification spontaneously, (without previous classes) for acetabular defects, inter-observer concordance was assessed using Cohen&#8217;s Kappa coefficient.  Results:  An interobserver agreement was obtained on average for the Paprosky classification of acetabular defects using the Cohen&#8217;s Kappa coefficient, the concordance analysis was done using the statistical program statistical package for the social sciences of 0.237.  Conclusions:  Both the null hypothesis (Kappa greater than 0.80 value considered optimal) and the alternative hypothesis (Kappa from 0.41 to 0.80 value equal to moderate to good) did not agree with our study (Kappa equal to 0.237) value equal to mild, in addition , it was shown that the greater the acetabular defect, the lower the interobserver agreement in surgeons in our institution.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Paprosky]]></kwd>
<kwd lng="es"><![CDATA[defecto acetabular]]></kwd>
<kwd lng="es"><![CDATA[concordancia]]></kwd>
<kwd lng="es"><![CDATA[prótesis de cadera]]></kwd>
<kwd lng="en"><![CDATA[Paprosky]]></kwd>
<kwd lng="en"><![CDATA[acetabular defect]]></kwd>
<kwd lng="en"><![CDATA[concordance]]></kwd>
<kwd lng="en"><![CDATA[hip prosthesis]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<label>1</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Deirmengianreali]]></surname>
<given-names><![CDATA[GK]]></given-names>
</name>
<name>
<surname><![CDATA[Zmitowski]]></surname>
<given-names><![CDATA[B]]></given-names>
</name>
<name>
<surname><![CDATA[O&#8217;Neil]]></surname>
<given-names><![CDATA[JT]]></given-names>
</name>
<name>
<surname><![CDATA[Hozack]]></surname>
<given-names><![CDATA[WJ]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Management of acetabular bone loss in revision total hip arthroplasty]]></article-title>
<source><![CDATA[J Bone Joint Surg Am]]></source>
<year>2011</year>
<volume>93</volume>
<numero>19</numero>
<issue>19</issue>
<page-range>1842-52</page-range></nlm-citation>
</ref>
<ref id="B2">
<label>2</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kurtz]]></surname>
<given-names><![CDATA[S]]></given-names>
</name>
<name>
<surname><![CDATA[Ong]]></surname>
<given-names><![CDATA[K]]></given-names>
</name>
<name>
<surname><![CDATA[Lau]]></surname>
<given-names><![CDATA[E]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Proyections of primary and revision hip and knee arthroplasty in the United States from de 2005 to 2030]]></article-title>
<source><![CDATA[J Bone Joint Surg Am]]></source>
<year>2007</year>
<volume>89</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>780-5</page-range></nlm-citation>
</ref>
<ref id="B3">
<label>3</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Bozic]]></surname>
<given-names><![CDATA[KJ]]></given-names>
</name>
<name>
<surname><![CDATA[Kurtz]]></surname>
<given-names><![CDATA[SM]]></given-names>
</name>
<name>
<surname><![CDATA[Lau]]></surname>
<given-names><![CDATA[E]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[The epidemiology of revision total hip arthroplasty in the United States]]></article-title>
<source><![CDATA[J Bone Joint Surg Am]]></source>
<year>2009</year>
<volume>91</volume>
<page-range>128-33</page-range></nlm-citation>
</ref>
<ref id="B4">
<label>4</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sporer]]></surname>
<given-names><![CDATA[SM]]></given-names>
</name>
<name>
<surname><![CDATA[Paprosky]]></surname>
<given-names><![CDATA[WG]]></given-names>
</name>
<name>
<surname><![CDATA[O&#8217;Rourke]]></surname>
<given-names><![CDATA[MR]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Managing bone loss in acetabular revision]]></article-title>
<source><![CDATA[Instr Course Lect]]></source>
<year>2006</year>
<volume>55</volume>
<page-range>287-97</page-range></nlm-citation>
</ref>
<ref id="B5">
<label>5</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Paprosky]]></surname>
<given-names><![CDATA[WG]]></given-names>
</name>
<name>
<surname><![CDATA[Bradford]]></surname>
<given-names><![CDATA[MS]]></given-names>
</name>
<name>
<surname><![CDATA[Younger]]></surname>
<given-names><![CDATA[TI]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Classification of bone defects in failed prostheses]]></article-title>
<source><![CDATA[Chir Organi Mov]]></source>
<year>1994</year>
<volume>79</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>285-91</page-range></nlm-citation>
</ref>
<ref id="B6">
<label>6</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Paprosky]]></surname>
<given-names><![CDATA[WG]]></given-names>
</name>
<name>
<surname><![CDATA[Perona]]></surname>
<given-names><![CDATA[PG]]></given-names>
</name>
<name>
<surname><![CDATA[Lawrence]]></surname>
<given-names><![CDATA[JM]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Acetabular defect classification and surgical reconstruction in revision arthroplasty. A 6-year follow-up evaluation]]></article-title>
<source><![CDATA[J Arthroplasty]]></source>
<year>1994</year>
<volume>9</volume>
<page-range>33-44</page-range></nlm-citation>
</ref>
<ref id="B7">
<label>7</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[D&#8217;Antonio]]></surname>
<given-names><![CDATA[JA]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Periprosthetic bone loss of the acetabulum: classification and management]]></article-title>
<source><![CDATA[Orthop Clin North Am]]></source>
<year>1992</year>
<volume>23</volume>
<page-range>279-90</page-range></nlm-citation>
</ref>
<ref id="B8">
<label>8</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Saleh]]></surname>
<given-names><![CDATA[KJ]]></given-names>
</name>
<name>
<surname><![CDATA[Holtzman]]></surname>
<given-names><![CDATA[J]]></given-names>
</name>
<name>
<surname><![CDATA[Gafni]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<name>
<surname><![CDATA[Saleh]]></surname>
<given-names><![CDATA[L]]></given-names>
</name>
<name>
<surname><![CDATA[Jaroszynski]]></surname>
<given-names><![CDATA[G]]></given-names>
</name>
<name>
<surname><![CDATA[Wong]]></surname>
<given-names><![CDATA[P]]></given-names>
</name>
<name>
<surname><![CDATA[Woodgate]]></surname>
<given-names><![CDATA[I]]></given-names>
</name>
<name>
<surname><![CDATA[Davis]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<name>
<surname><![CDATA[Gross]]></surname>
<given-names><![CDATA[AE]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Development, test reliability and validation of a classification for revision hip arthroplasty]]></article-title>
<source><![CDATA[J Orthop Res]]></source>
<year>2001</year>
<volume>19</volume>
<page-range>50-6</page-range></nlm-citation>
</ref>
<ref id="B9">
<label>9</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gustilo]]></surname>
<given-names><![CDATA[RB]]></given-names>
</name>
<name>
<surname><![CDATA[Pasternak]]></surname>
<given-names><![CDATA[HS]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Revision total hip arthroplasty with titanium ingrowth prosthesis and bone grafting for failed cemented femoral component loosening]]></article-title>
<source><![CDATA[Clin Orthop Relat Res]]></source>
<year>1988</year>
<volume>235</volume>
<page-range>111-9</page-range></nlm-citation>
</ref>
<ref id="B10">
<label>10</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gross]]></surname>
<given-names><![CDATA[AE]]></given-names>
</name>
<name>
<surname><![CDATA[Duncan]]></surname>
<given-names><![CDATA[CP]]></given-names>
</name>
<name>
<surname><![CDATA[Garbuz]]></surname>
<given-names><![CDATA[D]]></given-names>
</name>
<name>
<surname><![CDATA[Mohamed]]></surname>
<given-names><![CDATA[EM]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Revision arthroplasty of the acetabulum in association with loss of bone stock]]></article-title>
<source><![CDATA[Instr Course Lect]]></source>
<year>1999</year>
<volume>48</volume>
<page-range>57-66</page-range></nlm-citation>
</ref>
<ref id="B11">
<label>11</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Parry]]></surname>
<given-names><![CDATA[MC]]></given-names>
</name>
<name>
<surname><![CDATA[Whitehouse]]></surname>
<given-names><![CDATA[MR]]></given-names>
</name>
<name>
<surname><![CDATA[Mehendale]]></surname>
<given-names><![CDATA[SA]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[A comparison of the validity and reliability of established bone stock loss classification systems and the proposal of a novel classification system]]></article-title>
<source><![CDATA[Hip Int]]></source>
<year>2010</year>
<volume>20</volume>
<page-range>50-5</page-range></nlm-citation>
</ref>
<ref id="B12">
<label>12</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[O&#8217;Rourke]]></surname>
<given-names><![CDATA[MR]]></given-names>
</name>
<name>
<surname><![CDATA[Paprosky]]></surname>
<given-names><![CDATA[WG]]></given-names>
</name>
<name>
<surname><![CDATA[Rosenberg]]></surname>
<given-names><![CDATA[AG]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Use of structural allografts in acetabular revision surgery]]></article-title>
<source><![CDATA[Clin Orthop Relat Res]]></source>
<year>2004</year>
<volume>420</volume>
<page-range>113-21</page-range></nlm-citation>
</ref>
<ref id="B13">
<label>13</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gozzard]]></surname>
<given-names><![CDATA[C]]></given-names>
</name>
<name>
<surname><![CDATA[Blom]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<name>
<surname><![CDATA[Taylor]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<name>
<surname><![CDATA[Smith]]></surname>
<given-names><![CDATA[E]]></given-names>
</name>
<name>
<surname><![CDATA[Learmonth]]></surname>
<given-names><![CDATA[I]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[A comparison of the reliability and validity of bone stock loss classification systems used for revision hip surgery]]></article-title>
<source><![CDATA[J Arthroplasty]]></source>
<year>2003</year>
<volume>18</volume>
<numero>5</numero>
<issue>5</issue>
<page-range>638-42</page-range></nlm-citation>
</ref>
<ref id="B14">
<label>14</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Garbuz]]></surname>
<given-names><![CDATA[DS]]></given-names>
</name>
<name>
<surname><![CDATA[Masri]]></surname>
<given-names><![CDATA[BA]]></given-names>
</name>
<name>
<surname><![CDATA[Esdaile]]></surname>
<given-names><![CDATA[J]]></given-names>
</name>
<name>
<surname><![CDATA[Duncan]]></surname>
<given-names><![CDATA[CP]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Classification systems in orthopaedics]]></article-title>
<source><![CDATA[J Am Acad Orthop Surg]]></source>
<year>2002</year>
<volume>10</volume>
<page-range>290-7</page-range></nlm-citation>
</ref>
<ref id="B15">
<label>15</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Yu]]></surname>
<given-names><![CDATA[R]]></given-names>
</name>
<name>
<surname><![CDATA[Hofstaetter]]></surname>
<given-names><![CDATA[JG]]></given-names>
</name>
<name>
<surname><![CDATA[Sullivan]]></surname>
<given-names><![CDATA[T]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Validity and reliability of the Paprosky acetabular defect classification]]></article-title>
<source><![CDATA[Clin Orthop Relat Res]]></source>
<year>2013</year>
<volume>471</volume>
<numero>7</numero>
<issue>7</issue>
<page-range>2259-65</page-range></nlm-citation>
</ref>
<ref id="B16">
<label>16</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Campbell]]></surname>
<given-names><![CDATA[DG]]></given-names>
</name>
<name>
<surname><![CDATA[Garbuz]]></surname>
<given-names><![CDATA[DS]]></given-names>
</name>
<name>
<surname><![CDATA[Masri]]></surname>
<given-names><![CDATA[BA]]></given-names>
</name>
<name>
<surname><![CDATA[Duncan]]></surname>
<given-names><![CDATA[CP]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Reliability of acetabular bone defect classification systems in revision total hip arthroplasty]]></article-title>
<source><![CDATA[J Arthroplasty]]></source>
<year>2001</year>
<volume>16</volume>
<page-range>83-6</page-range></nlm-citation>
</ref>
<ref id="B17">
<label>17</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Davis]]></surname>
<given-names><![CDATA[AM]]></given-names>
</name>
<name>
<surname><![CDATA[Schemitsch]]></surname>
<given-names><![CDATA[EH]]></given-names>
</name>
<name>
<surname><![CDATA[Gollish]]></surname>
<given-names><![CDATA[JD]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Classifying failed hip arthroplasty: generalizability of reliability and validity]]></article-title>
<source><![CDATA[Clin Orthop Relat Res]]></source>
<year>2003</year>
<volume>415</volume>
<page-range>171-9</page-range></nlm-citation>
</ref>
<ref id="B18">
<label>18</label><nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sackett]]></surname>
<given-names><![CDATA[DL]]></given-names>
</name>
<name>
<surname><![CDATA[Haynes]]></surname>
<given-names><![CDATA[BR]]></given-names>
</name>
<name>
<surname><![CDATA[Tugwell]]></surname>
<given-names><![CDATA[P]]></given-names>
</name>
<name>
<surname><![CDATA[Guyatt]]></surname>
<given-names><![CDATA[GH]]></given-names>
</name>
</person-group>
<source><![CDATA[Clinical epidemiologya basic science for clinical medicine]]></source>
<year>1991</year>
<edition>2</edition>
<publisher-loc><![CDATA[Boston ]]></publisher-loc>
<publisher-name><![CDATA[Brown and Company]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B19">
<label>19</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Masri]]></surname>
<given-names><![CDATA[BA]]></given-names>
</name>
<name>
<surname><![CDATA[Masterson]]></surname>
<given-names><![CDATA[EL]]></given-names>
</name>
<name>
<surname><![CDATA[Duncan]]></surname>
<given-names><![CDATA[CP]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[The classification and radiographic evaluation of bone loss in revision hip arthroplasty]]></article-title>
<source><![CDATA[Orthop Clin North Am]]></source>
<year>1998</year>
<volume>29</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>219-27</page-range></nlm-citation>
</ref>
<ref id="B20">
<label>20</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Telleria]]></surname>
<given-names><![CDATA[JJM]]></given-names>
</name>
<name>
<surname><![CDATA[Gee]]></surname>
<given-names><![CDATA[AO]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Paprosky classification of acetabular bone loss]]></article-title>
<source><![CDATA[Clin Orthop Relat Res]]></source>
<year>2013</year>
<volume>471</volume>
<numero>119</numero>
<issue>119</issue>
<page-range>3725-30</page-range></nlm-citation>
</ref>
<ref id="B21">
<label>21</label><nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Johanson]]></surname>
<given-names><![CDATA[NA]]></given-names>
</name>
<name>
<surname><![CDATA[Driftmier]]></surname>
<given-names><![CDATA[KR]]></given-names>
</name>
<name>
<surname><![CDATA[Cerynik]]></surname>
<given-names><![CDATA[DL]]></given-names>
</name>
<name>
<surname><![CDATA[Stehman]]></surname>
<given-names><![CDATA[CC]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Grading acetabular defects: the need for a universal and valid system]]></article-title>
<source><![CDATA[J Arthroplasty]]></source>
<year>2010</year>
<volume>25</volume>
<numero>3</numero>
<issue>3</issue>
<page-range>425-31</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
