Measurement of acetabular wall indices: comparison between CT and plain radiography

Nazaroff, J.; Mark, Bryan J.; Learned, James; Wang, Dean

doi:10.1093/jhps/hnab008

Cited by 8 publications

(8 citation statements)

References 30 publications

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“…In this case, the anterior coverage of the hip joint was greatly overestimated on the pelvic AP radiograph because of the effect of the AIIS. This can also explain why there is only a moderate correlation between AWI on pelvic radiographs and CT. [39] In the same patient, after the acetabulum was reoriented in PAO, the supporting area of the acetabulum rotated laterally and anteriorly. As the anterior hip coverage signi cantly increased, the ACEA increased signi cantly as well (Fig.…”

Section: Discussionmentioning

confidence: 92%

Can we determine anterior hip coverage from pelvic anteroposterior radiographs? A study of patients with hip dysplasia

Cheng

Zhang

Sun

et al. 2023

Preprint

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Purpose: Insufficient coverage causes hip joint instability and results in hip pain. Anterior hip coverage can be determined on both pelvic anteroposterior (AP) radiographs and false profile (FP) radiographs. Four parameters are commonly used to determine the anterior coverage on pelvic AP radiographs: the crossover index, crossover sign, anterior wall index (AWI), and rule of thirds. This study aims to clarify the relationship between these 4 parameters on AP radiographs and the anterior center edge angle (ACEA) on FP radiographs. Methods: In this study, 53 patients who underwent periacetabular osteotomy for hip dysplasia at our center between July 2020 and October 2020 were retrospectively reviewed. Four parameters on AP radiographs and the ACEA on FP radiographs before surgery and 6 months after surgery were measured and compared for each hip. Results: Upon examining the 53 hips in this study, there was no correlation between either the crossover index and the ACEA (P=0.66) or the crossover sign before surgery. The postoperative correlation between the crossover index and the ACEA was weak (r=0.36, P=0.007), and that between the crossover sign and the ACEA was moderate (r=0.41, P=0.003). There was a weak correlation between the AWI and ACEA both before (r=0.288, P=0.036) and after (r=0.349, P=0.011) the operation. Evaluation of the anterior coverage by the rule of thirds was also not consistent when determining the anterior coverage with the ACEA. Conclusion: Anterior coverage on AP radiographs is largely inconsistent with ACEA on FP radiographs, especially before the surgery. It is recommended to take FP radiographs routinely for determining anterior hip coverage.

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Section: Discussionmentioning

confidence: 92%

Can we determine anterior hip coverage from pelvic anteroposterior radiographs? A study of patients with hip dysplasia

Cheng

Zhang

Sun

et al. 2023

Preprint

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“…However, some authors have reported that values of radiographic acetabular wall indices are consistently larger for AWI and smaller for PWI relative to CT-based measurements of the same indices and that a standardization of measurements is needed. 24 Radiographic ACEA has traditionally been used to quantify anterior coverage, with normal values ranging from 25°to 40°. 8,22 A recent multicenter prospective cohort study suggested that obtaining a false-profile radiograph adds strong value to the diagnosis of hip dysplasia in the young adult in cases that would otherwise remain missed with a single anteroposterior view.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Anterior Center-Edge Angle Is Less Reliable Than Anterior Wall Index to Predict Anterior Coverage of the Femoral Head

et al. 2023

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Background: No consensus is available regarding which radiographic measurement most accurately correlates with anterior coverage of the femoral head. Purpose: (1) To determine the correlation between 2 measurements of anterior wall coverage: total anterior coverage (TAC) calculated from radiographs and equatorial anterior acetabular sector angle (eAASA) calculated from computed tomography (CT) scans; (2) to define the correlation between anterior center-edge angle (ACEA) and anterior wall index (AWI) with TAC and eAASA; and (3) to investigate what other radiographic metrics may help predict anterior coverage. Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: The authors retrospectively reviewed 77 hips (48 patients) for which radiographs and CT scans were obtained for reasons other than hip-related pain. Mean age of the population was 62 ± 22 years; 48 (62%) hips were from female patients. Two observers measured lateral center-edge angle (LCEA), AWI, Tönnis angle, ACEA, CT-based pelvic tilt, and CT-based acetabular version, with all Bland-Altman plots within 95% agreement. Correlation between intermethod measurements was estimated with a Pearson coefficient. Linear regression was used to test the ability of baseline radiographic measurements to predict both TAC and eAASA. Results: Pearson coefficients were r = 0.164 (ACEA vs TAC; P = .155), r = 0.170 (ACEA vs eAASA; P = .140), r = 0.58 (AWI vs TAC; P = .0001), and r = 0.693 (AWI vs eAASA; P < .0001). Multiple linear regression model 1 showed that AWI (β = 17.8; 95% CI, 5.7 to 29.9; P = .004), CT acetabular version (β = −0.45; 95% CI, −0.71 to −0.22; P = .001), and LCEA (β = 0.33; 95% CI, 0.19 to 0.47; P = .001) were useful to predict TAC. Multiple linear regression model 2 revealed that AWI (β = 25; 95% CI, 15.67 to 34.4; P = .001), CT acetabular version (β = −0.48; 95% CI, −0.67 to −0.29; P = .001), CT pelvic tilt (β = 0.26; 95% CI, 0.12 to 0.4; P = .001), and LCEA (β = 0.21; 95% CI, 0.1 to 0.3; P = .001) accurately predicted eAASA. Model-based estimates and 95% CIs using 2000 bootstrap samples from the original data were 6.16 to 28.6 for AWI in model 1 and 15.1 to 34.26 for AWI in model 2. Conclusion: There was a moderate to strong correlation between AWI and both TAC and eAASA, whereas ACEA correlated weakly with the former measurements, thus not being useful to quantify anterior acetabular coverage. Other variables such as LCEA, acetabular version, and pelvic tilt may also help predict anterior coverage in asymptomatic hips.

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“…Thus, low-dose CT assessment appears to offer critical insight into anterior coverage and deficiency that is not gained from plain radiographs alone. Nazaroff et al 25 previously attempted to correlate measurements of AWI and PWI on plain radiographs to similar measurements made on CT in a general population. They found a moderate correlation between the 3D and plain radiographic measurements for the AWI, while a poor correlation was seen for the PWI.…”

Section: Discussionmentioning

confidence: 99%

Defining the Borderline Dysplastic Hip: High Variability in Acetabular Coverage and Femoral Morphology on Low-Dose Computed Tomography

et al. 2023

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Background: Borderline acetabular dysplasia is commonly radiographically defined as a lateral center-edge angle (LCEA) of 20° to 25°. While the variability of plain radiographic assessment of this population has been reported, an understanding of the variability of 3-dimensional (3D) hip morphology remains to be better defined. Purpose: To investigate the variability of 3D hip morphology present on low-dose computed tomography (CT) in the setting of symptomatic borderline acetabular dysplasia and to determine if plain radiographic parameters correlate with 3D coverage. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 70 consecutive hips with borderline acetabular dysplasia undergoing hip preservation surgery were included in the current study. Plain radiographic evaluation included LCEA, acetabular inclination, anterior center-edge angle (ACEA), anterior wall index (AWI), posterior wall index (PWI), and alpha angles on anteroposterior, 45° Dunn, and frog-leg views. All patients underwent low-dose pelvic CT for preoperative planning, which allowed detailed characterization of 3D morphology relative to normative data. Acetabular morphology was assessed with radial acetabular coverage (RAC) calculated according to standardized clockface positions from 8:00 (posterior) to 4:00 (anterior). Coverages at 10:00, 12:00, and 2:00 were classified as normal, undercoverage, or overcoverage relative to 1 SD from the mean of normative RAC values. Femoral morphology was assessed with femoral version, alpha angle (measured at 1:00 increments), and maximum alpha angle. Correlation was assessed with the Pearson correlation coefficient ( r). Results: Lateral coverage (12:00 RAC) was deficient in 74.1% of hips with borderline dysplasia. Anterior coverage (2:00 RAC) was highly variable, with 17.1% undercoverage, 72.9% normal, and 10.0% overcoverage. Posterior coverage (10:00 RAC) was also highly variable, with 30.0% undercoverage, 62.9% normal, and 7.1% overcoverage. The 3 most common patterns of coverage were isolated lateral undercoverage (31.4%), normal coverage (18.6%), and combined lateral and posterior undercoverage (17.1%). The mean femoral version was 19.7°± 10.6° (range, −4° to 59°), with 47.1% of hips having increased femoral version (>20°). The mean maximum alpha angle was 57.2° (range, 43°-81°), with 48.6% of hips having an alpha angle ≥ 55°. The ACEA and AWI were poorly correlated with radial anterior coverage ( r = 0.059 and 0.311, respectively), while the PWI was strongly correlated with radial posterior coverage ( r = 0.774). Conclusion: Patients with borderline acetabular dysplasia demonstrate highly variable 3D deformities, including anterior, lateral, and posterior acetabular coverage; femoral version; and alpha angle. Plain radiographic assessments of anterior coverage are poorly correlated with anterior 3D coverage on low-dose CT.

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Measurement of acetabular wall indices: comparison between CT and plain radiography

Cited by 8 publications

References 30 publications

Can we determine anterior hip coverage from pelvic anteroposterior radiographs? A study of patients with hip dysplasia

Can we determine anterior hip coverage from pelvic anteroposterior radiographs? A study of patients with hip dysplasia

Anterior Center-Edge Angle Is Less Reliable Than Anterior Wall Index to Predict Anterior Coverage of the Femoral Head

Defining the Borderline Dysplastic Hip: High Variability in Acetabular Coverage and Femoral Morphology on Low-Dose Computed Tomography

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