title: Radiographic Assessment of Femoral Stem Torsion in Total Hip Arthroplasty-A Comparison of a Caput-Collum-Diaphyseal Angle-Based Technique With the Budin View.
abstract: Correct assessment of femoral stem torsion is crucial in total hip arthroplasty (THA). In this study, we aimed to compare a recently published novel method based on anteroposterior (AP) hip radiographs using the projected caput-collum-diaphyseal (CCD) angle (AP CCD) with the modified posteroanterior Budin view.
  
  
  
  AP radiographs, modified Budin views, and 3-dimensional computed tomography (3D-CT) images were obtained in 30 patients after minimally invasive, cementless THA. Radiographic measurements performed by 4 observers twice in a 6-week interval were compared with 3D-CT measurements. Furthermore, correlations between the radiographic deviation to 3D-CT and patient specific characteristics were evaluated.
  
  
  
  We found a mean difference of 2.2 ± 6.8° between AP CCD and 3D-CT measurements of femoral stem torsion and -0.5 ± 4.2° between the modified Budin view and 3D-CT. We found a high correlation between mean radiographic and 3D-CT stem torsion (r = 0.78, P < .001 for AP CCD and r = 0.84, P < .001 for Budin view). The observers had excellent agreements within (intraclass correlation coefficient, ≥0.88 for AP CCD and intraclass correlation coefficient, ≥0.94 for Budin view) and between (mean concordance correlation coefficient, ≥0.79 for AP CCD and concordance correlation coefficient, ≥0.86 for Budin view) their radiographic measurements.
  
  
  
  Both radiographic methods enable a simple orientation and a practical conventional radiographic estimation of stem torsion on hip radiographs after THA. However, CT remains the golden standard for exact estimation of stem torsion.
authors.affiliation: Department of Orthopedic Surgery, Regensburg University Medical Center, Bad Abbach, Germany.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Woerner
authors.affiliation: Department of Orthopedic Surgery, Regensburg University Medical Center, Bad Abbach, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Weber
authors.affiliation: Department of Orthopedic Surgery, Regensburg University Medical Center, Bad Abbach, Germany.
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Craiovan
authors.affiliation: Department of Orthopedic Surgery, Regensburg University Medical Center, Bad Abbach, Germany.
authors.forename: H Robert
authors.initials: HR
authors.lastname: Springorum
authors.affiliation: Department of Orthopedic Surgery, Regensburg University Medical Center, Bad Abbach, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
authors.affiliation: Department of Orthopedic Surgery, Regensburg University Medical Center, Bad Abbach, Germany.
authors.forename: Tobias F
authors.initials: TF
authors.lastname: Renkawitz
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D017760:Bone Malalignment / Q000000981:diagnostic imaging*; D018483:Diaphyses / Q000000981:diagnostic imaging; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011184:Postoperative Period; D011446:Prospective Studies; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods; D014102:Torsion Abnormality / Q000000981:diagnostic imaging*
keywords: hip; hip biomechanics; radiography; stem torsion; total hip arthroplasty