Changes

====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.

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>

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: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/>

[[File:Femoral offset in hemiarthroplasty(crop).jpg|thumb|170px|Femoral offset in hemiarthroplasty.<ref name="JonesBriffa2017">{{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>.]] The main measure measures after hemiarthroplasty is femoral hemiarthroplastyare:*'''Leg length discrepancy''' as in total arthroplasty above.*'''Femoral (neck) offset''', which is defined as the perpendicular distance between the intramedullary or longitudinal axis of the femur and the center of rotation of the native or prosthetic femoral head. <ref name="JonesBriffa2017"/> An unnatural offset, as compared to the contralateral side, of less than 33 mm is associated with hip dislocation.<ref name="JonesBriffa2017NinhSethi2009">{{cite journal|last1=Ninh|first1=Christopher C.|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 Arthroplasty|volume=24|issue=5|year=2009|pages=768–774|issn=08835403|doi=10.1016/j.arth.2008.02.019}}</ref>

*Prosthesis configuration. If the report is likely to undergo double reading, the parameters need to may be given in numbers even if within normal limits.