Changes

[[File:Hip prosthesis components.jpg|thumb|160px|Main components of a hip prosthesis<ref>{{cite web|url=http://illumin.usc.edu/61/total-hip-replacement/|title=Total Hip Replacement|website=[[University of Southern California]]|author=Andrew Still|date=2002-11-02|accessdate=2017-01-05}}</ref>]]{{AuthorsTop

For '''[[X-ray of the hip joint]]''' in the presence of a prosthesis, this article first deals with the first postoperative image which is more focused at prosthesis configuration, and separately describes subsequent follow-ups which are more focused at complications. ==Quality checking==*The referral or complementary information needs to specify the type of prosthesis and when it was inserted.<ref name=SOA>{{cite web|url=http://www.ortopedi.se/pics/1/5/Hoftradiologisk_undersokning.pdf|title=Hip - Radiologic evaluation of prosthetic surgery (Swedish title: HÖFT - Radiologisk undersökning vid proteskirurgi)|website=Swedish Orthopaedic Association (SOA)|author=Radiologists: Torsten Boegård, Mats Geijer, Marianne Petrén-Mallmin. Orthopedic surgeons: Lennart Sanzén, Christer Strömberg, Torbjörn Ahl}} Publication #18, 2006</ref>*Images that need to be available include the first postoperative ones, as well as the most recent previous exam.<ref name=SOA/> ==First postoperative image: Configuration==

===Planning===Necessary projections are:*Frontal and axial image of the hip joint*Frontal image of the inferior parts of the hip bone (to include the [[ischium]] bones for measurements). ===Evaluation===Evaluate:*Prosthesis configuration*Cement coverage, where applicable*Any intraoperative fractures ====Configuration of total arthroplasty====The direction of the acetabular cup influences the range of motion of the leg, and also affects the risk of dislocation.<ref name=Watt/> For this purpose, the ''acetabular inclination'' and the ''acetabular anteversion'' are measurements of cup angulation in the [[coronal plane]] and the [[sagittal plane]], respectively.<gallery widths="230330" heights="150">File:Acetabular inclination of hip prosthesis.jpg|'''Acetabular inclination'''.<ref name=Vanrusselt2015/> This parameter is calculated on an anteroposterior radiograph as the angle between a line through the lateral and medial margins of the acetabular cup and the ''transischial line'' which is tangential to the inferior margins of the [[ischium]] bones.<ref name=Vanrusselt2015>{{cite journal|last1=Vanrusselt|first1=Jan|last2=Vansevenant|first2=Milan|last3=Vanderschueren|first3=Geert|last4=Vanhoenacker|first4=Filip|title=Postoperative radiograph of the hip arthroplasty: what the radiologist should know|journal=Insights into Imaging|volume=6|issue=6|year=2015|pages=591–600|issn=1869-4101|doi=10.1007/s13244-015-0438-5|pmid=26487647}}</ref>

<gallery widths="230330" heights="150">File:Acetabular anteversion of hip prosthesis.jpg|'''Acetabular anteversion'''.<ref name="ShinLee2015"/> This parameter is calculated on a lateral radiograph as the angle between the [[transverse plane]] and a line going through the (anterior and posterior) margins of the acetabular cup.<ref name="ShinLee2015">{{cite journal|last1=Shin|first1=W. C.|last2=Lee|first2=S. M.|last3=Lee|first3=K. W.|last4=Cho|first4=H. J.|last5=Lee|first5=J. S.|last6=Suh|first6=K. T.|title=The reliability and accuracy of measuring anteversion of the acetabular component on plain anteroposterior and lateral radiographs after total hip arthroplasty|journal=The Bone & Joint Journal|volume=97-B|issue=5|year=2015|pages=611–616|issn=2049-4394|doi=10.1302/0301-620X.97B5.34735}}</ref>File:Range of acetabular anteversion.png|Acetabular anteversion is normally between 5 and 25°.<ref name=Watt/> An anteversion below or above this range increases the risk of dislocation.<ref name=Watt/> There is an [[intra-individual variability]] in this method because the pelvis may be tilted in various degrees in relation to the transverse plane.<ref name=Watt/></gallery><gallery widths="330" heights="150">File:Leg length discrepancy after hip replacement.jpg|'''Leg length discrepancy''' after hip replacement is calculated as the vertical distance between the middle of the minor trochanters, using the acetabular tear drops<ref name=Vanrusselt2015/> or the transischial line<ref name=Watt/> as references for the horizontal plane. A discrepancy of up to 1&nbsp;cm is generally tolerated.<ref name=Vanrusselt2015/><ref name=Watt/>File:Center of rotation of hip prosthesis.jpg|'''Center of rotation''': The horizontal center of rotation is calculated as the distance between the acetabular teardrop and the center of the head (or caput) of the prosthesis and/or the native femoral head on the contralateral side.<ref name=Vanrusselt2015/> The vertical center of rotation instead uses the transischial line for reference.<ref name=Vanrusselt2015/> The parameter should be equal on both sides.<ref name=Vanrusselt2015/>

 ====Configuration of hemiarthroplasty====[[File:Femoral offset in hemiarthroplasty (crop).jpg|thumb|170px|Femoral offset in hemiarthroplasty.<gallery widthsref name="230JonesBriffa2017">{{cite journal|last1=Jones|first1=Carl|last2=Briffa|first2=Nikolai|last3=Jacob|first3=Joshua|last4=Hargrove|first4=Richard|title=The Dislocated Hip Hemiarthroplasty: Current Concepts of Etiological factors and Management|journal=The Open Orthopaedics Journal|volume=11|issue=Suppl-7, M4|year=2017|pages=1200–1212|issn=1874-3250|doi=10.2174/1874325001711011200}}</ref>.]] FileThe main measures after hemiarthroplastyare:*'''Leg length discrepancy after hip replacement''' as in total arthroplasty above.jpg|*'''Femoral (neck) offset'Leg length discrepancy'' after hip replacement , which is calculated defined as the vertical perpendicular distance between the middle intramedullary or longitudinal axis of the minor trochanters, using femur and the center of rotation of the acetabular tear dropsnative or prosthetic femoral head.<ref name=Vanrusselt2015"JonesBriffa2017"/> or the transischial lineAn offset of less than 33 mm is associated with hip dislocation.<ref name=Watt/"NinhSethi2009"> as references for the horizontal plane{{cite journal|last1=Ninh|first1=Christopher C. A discrepancy |last2=Sethi|first2=Anil|last3=Hatahet|first3=Mohammed|last4=Les|first4=Clifford|last5=Morandi|first5=Massimo|last6=Vaidya|first6=Rahul|title=Hip Dislocation After Modular Unipolar Hemiarthroplasty|journal=The Journal of up to 1&nbsp;cm is generally toleratedArthroplasty|volume=24|issue=5|year=2009|pages=768–774|issn=08835403|doi=10.1016/j.arth.2008.02.019}}</ref name> ====Cement coverage====Vanrusselt2015/>Cement coverage is regarded as acceptable when there are no translucent zones on an anteroposterior image in at least 6 of 7 Gruen-zones.<ref name=WattSOA/> [[File:Center of rotation of hip Hip prosthesiszones by DeLee and Charnley system, and Gruen system.jpg|''Center thumb|250px|center|Hip prosthesis zones according to DeLee and Charnley,<ref>{{cite book|title=The Adult Hip, Volume 1|url=https://books.google.com/books?id=-fwULYB1gJIC&pg=PA958|author=John J. Callaghan, Aaron G. Rosenberg, Harry E. Rubash|publisher=Lippincott Williams & Wilkins|year=2007|isbn=978-0-7817-5092-9|page=958}}</ref> and Gruen.<ref>{{cite journal|last1=Neumann|first1=Daniel R.P.|last2=Thaler|first2=Christoph|last3=Hitzl|first3=Wolfgang|last4=Huber|first4=Monika|last5=Hofstädter|first5=Thomas|last6=Dorn|first6=Ulrich|title=Long-Term Results of rotation'': a Contemporary Metal-on-Metal Total Hip Arthroplasty|journal=The horizontal center Journal of rotation is calculated as Arthroplasty|volume=25|issue=5|year=2010|pages=700–708|issn=0883-5403|doi=10.1016/j.arth.2009.05.018}}</ref> These are used to describe the distance between the acetabular teardrop and the center location of for example areas of loosening.]] Absence of the head cement in zone 7 (or caputmedially-proximally) needs to be noted. On a lateral image, the distal tip of the prosthesis should be centered, and/or not be in contact with the native femoral head on the contralateral sidecortex.<ref name=Vanrusselt2015SOA/> The vertical center cup should not have translucent zones in zone 1 and 2. It is acceptable to have translucent zones in parts of rotation instead uses the transischial line for referencezone 3.<ref name=Vanrusselt2015SOA/> The parameter should be equal on both sides ====Fractures====Have at least a glance at bony contours around the prosthesis in order to detect intraoperative fractures.<ref name=Vanrusselt2015/gallery>File:Intraoperative acetabular fracture, annotated.jpg|Intraoperative acetabular fracture

===Report===The postoperative report should include:<ref name=SOA/>*Prosthesis configuration. If the report is likely to undergo double reading, the parameters may be given in numbers even if within normal limits.*Cement coverage. {|class="wikitable"|+ Normal report! Basic !! Comprehensive|-| (Total) hip replacement with unremarkable configuration and cement coverage | Post-operative images of total hip replacement with unremarkable configuration:*Acetabular inclination: ___°*Acetabular anteversion: ___°*The right leg is ___ longer than the left, as measured at the minor trochanters.*Equal centers of rotation.*Proper cement coverage.|}{{Public Domain examples}}{{Reporting}} ==Further follow-ups: Complications==Further follow-ups after the initial postoperative image are focused on various complications. 

<gallerywidths=200 heights=200>

On radiography, it is normal to see thin radiolucent areas of less than 2&nbsp;mm around hip prosthesis components, or between a cement mantle and bone. However, these may still indicate loosening of the prosthesis if they are new or changing, and areas greater than 2&nbsp;mm may be harmless if they are stable.<ref name="RothMaertz2012"/> The most important prognostic factors of cemented cups are absence of radiolucent lines in DeLee and Charnley zone I, as well as adequate cement mantle thickness.<ref>{{cite book|title=The Well-Cemented Total Hip Arthroplasty: Theory and Practice|url=https://books.google.se/books?id=PQ6NZAeJUXcC&pg=PA337&lpg=PA336|author=Steffen Breusch, Henrik Malchau|publisher=Springer Science & Business Media|year=2005|isbn=978-3-540-24197-3|page=336}}</ref> In the first year after insertion of uncemented femoral stems, it is normal to have mild subsidence (less than 10&nbsp;mm).<ref name="RothMaertz2012">{{cite journal|last1=Roth|first1=Trenton D.|last2=Maertz|first2=Nathan A.|last3=Parr|first3=J. Andrew|last4=Buckwalter|first4=Kenneth A.|last5=Choplin|first5=Robert H.|title=CT of the Hip Prosthesis: Appearance of Components, Fixation, and Complications|journal=RadioGraphics|volume=32|issue=4|year=2012|pages=1089–1107|issn=0271-5333|doi=10.1148/rg.324115183}}</ref>  ===Report===Further follow-up reports should include at least:*Dates of the images used for comparison*Absence of change in position, or a description of any change.<ref name=SOA/>*Absence or of loosening, or a description of it.<ref name=SOA/> {{Reporting}}

==References=={{ReflistBottom}}