Pelvic orientation and assessment of hip dysplasia in adults

Jacobsen, Søren; Sonne‐Holm, Stig; Lund, B.; Søballe, Kjeld; Kiaer, T; Rovsing, Hans; Monrad, Henrik

doi:10.1080/00016470410004094

Cited by 62 publications

(53 citation statements)

References 23 publications

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“…Except for Tönnis angle, as the pelvis tilted anteriorly toward or posteriorly away from the beam, the acetabular parameters showed increased or decreased acetabular coverage, respectively. Consistent with our findings from a cadaver with varying abnormal morphologic features of the pincer, Jacobsen et al [14] found rotation and tilt affected lateral center-edge angle and Sharp angle in two cadavers with normal morphologic features of the hip. Siebenrock et al [26] found an anterior tilt of 9°and rotation of 6°away from the x-ray beam produced a crossover sign in every pelvis.…”

Section: Discussionsupporting

confidence: 91%

Reliability of Overcoverage Parameters With Varying Morphologic Pincer Features: Comparison of EOS® and Radiography

Monazzam¹,

Agashe²,

Hosalkar³

2013

Clinical Orthopaedics &Amp; Related Research

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Background Multiple radiographic parameters used for diagnosis and quantification of morphologic pincer features have emerged, but the degree to which pelvic tilt or rotation affects conventional radiography and EOS 1 is unknown. Question/purposes We asked: (1) What is the reliability of EOS 1 and conventional radiography at increasing sizes of morphologic pincer features with varying degrees of tilt and rotation? (2) What is the effect of tilt and rotation on acetabular overcoverage measurements? Methods Using a dry cadaveric pelvis, AP conventional radiographs and EOS 1 images were taken at intervals of increasing modeled pincer size with 0°to 15°varying tilt and rotation. Lateral center-edge angle, Sharp angle, Tönnis angle, crossover sign, and retroversion index were measured on all images. Statistical analysis was conducted. Results The intermodality intraclass correlation coefficients for conventional radiography and EOS 1 radiography across all pincer sizes, rotations, and tilts were excellent (0.93-0.98). Crossover sign was in perfect agreement in conventional radiography and EOS 1 . Rotation of the hip away from the beam source and/or increased anterior tilt falsely increased all overcoverage parameters except for Tönnis angle. Rotation away from the beam of 10°or greater or anterior tilt of 5°or greater produced a false-positive crossover sign. Conclusions EOS 1 radiography maintained excellent reliability in comparison to conventional radiography but both were equally vulnerable to the effects of tilt and rotation for quantification of hip parameters used in acetabular overcoverage assessment. A standardized pelvic radiograph ensuring that the pelvis is not excessively tilted or rotated should be used for assessing acetabular overcoverage parameters.

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Section: Discussionsupporting

confidence: 91%

Reliability of Overcoverage Parameters With Varying Morphologic Pincer Features: Comparison of EOS® and Radiography

Monazzam¹,

Agashe²,

Hosalkar³

2013

Clinical Orthopaedics &Amp; Related Research

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“…Accurate assessment of acetabular version and anterior and posterior femoral head coverage can be difficult, and changes in patient positioning can lead to errors in measurement [4,24,45,48]. Two-dimensional CT studies have become an integral part of diagnosis and preoperative planning, especially when assessing deficiencies in the transverse plane [5,26,29,33,41,59].…”

Section: Introductionmentioning

confidence: 99%

Pelvic Positioning Creates Error in CT Acetabular Measurements

Bosse¹,

Lee

Henderson

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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Background CT allows for accurate measurement of acetabular orientation and shape, but malpositioning of the pelvis may lead to measurement variance. Purpose We therefore sought to determine: (1) whether acetabular anteversion measurements using the femoral head centers differed from those using the posterior ischia, and (2) the extent to which changing obliquity, rotation, and tilt of a pelvis in a CT scanner affected the measurement of acetabular variables. Methods A radiopaque human pelvis model with articulated hips was suspended from a plastic sheet as part of an adjustable frame. Changes in the transverse and sagittal planes created rotation and tilt, while rotating the frame in the coronal plane created obliquity. CT scans were obtained, varying the combinations of obliquity, rotation, and tilt by intervals of 5°, up to 20°. Acetabular anteversion (AA), anterior acetabular sector angle (AASA), posterior acetabular sector angle (PASA), and horizontal acetabular sector angle (HASA) were measured. Results The two methods for measuring AA yielded values differing by 1°to 4°but correlated (r = 0.981) across the spectrum of pelvis positioning. Pelvic obliquity and tilt were linearly associated with changes in the measurements. For each 1°-increase in pelvic obliquity, AA changed À0.4°, and AASA, PASA, and HASA changed 1.93°, 0.99°, and 2.80°, respectively. For each 1°-increase in pelvic tilt, AA changed 0.8°, and AASA, PASA, and HASA changed À1.07°, 0.52°, and À0.51°, respectively. Rotation had no affect on the variables. Conclusions Small changes in pelvic obliquity and tilt were associated with variances in acetabular measurements. The measured changes were directly proportional to the changes in obliquity and tilt, and were additive. Pelvic rotation created no changes in measurement. Clinical Relevance Incorrect interpretation of acetabular anteversion and coverage may lead to unsatisfactory acetabular fragment positioning during reorientational surgery. Although intraoperative positioning of an acetabular fragment may not be as precise as the tools for preoperative planning, it is important for a surgeon to have the most precise data available for planning a procedure, and know where error can occur in collecting the data.Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.

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“…In a previous cadaver study we found that extreme pelvic rotation and inclination/reclination had significant influence on hip dysplasia assessment [12]. To stay inside ±3°of error of measurements of the CE angle, FOI inclusion limits of 0.7-1.8 were applied to radiographs.…”

Section: Exclusion Of Radiographsmentioning

confidence: 99%