|Year : 2020 | Volume
| Issue : 1 | Page : 37-42
The iliac oblique judet view to assess post-operative healing and evaluate anterior acetabular coverage following bernese periacetabular osteotomy
Robert C Kollmorgen1, Brian Lewis2, Carolyn Hutyra2, Steven Olson3
1 Department of Orthopaedic Surgery, University of California San Francisco, Fresno, CA, USA
2 Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA
3 Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC, USA
|Date of Submission||12-Jan-2020|
|Date of Acceptance||22-Sep-2020|
|Date of Web Publication||21-May-2021|
Dr. Robert C Kollmorgen
Department of Orthopaedic Surgery, University of California San Francisco, 2823 Fresno Street, Fresno, CA 93721
Source of Support: None, Conflict of Interest: None
Background: Radiographic measurements defining anterior acetabular coverage show variability in the literature. A reliable radiographic measure to evaluate anterior acetabular coverage following the Bernese Periacetabular Osteotomy during the nonweight bearing healing phase would be helpful to evaluate the quality of reduction.
Questions/Purposes: (1) To compare a new radiographic means to measure the Anterior Center Edge Angle (ACEA) on the iliac oblique (IO) Judet view with the ACEA on False Profile (FP) view with respect to intra-and inter-observer reliability and (2) To describe the utility of the Judet views as an alternative approach monitor postosteotomy healing.
Methods: We defined and validated ACEA measurements for the FP and IO Judet View for 11 post-surgical periacetabular osteotomy (PAO) patients. Intraclass correlation coefficients with 95% confidence intervals were calculated for intra- and inter-observer reliability, Bland Altman plot was created, and paired t-tests were performed between the two sample measurements.
Results: The intra-observer reliability for ACEA measurements was 0.987 and 0.983 for the FP and IO Judet views, respectively. The inter-observer reliability correlation coefficients were 0.978 and 0.934 for the FP and IO Judet views, respectively. When comparing measurements between the two surgeons, the mean standard deviation (SDV) for the FP group was within ± 2.5° for all observations. For the IO Judet group, the SDV was within ± 3.5°.
Conclusion: This study demonstrates a new method of measuring the ACEA utilizing the IO Judet view for nonweight bearing postoperative PAO patients. The results of this study suggest that FP view is no longer necessary postoperatively for this population.
Level of Evidence: III, diagnostic study.
Keywords: Anterior Center Edge Angle, hip dysplasia, periacetabular osteotomy, radiograph
|How to cite this article:|
Kollmorgen RC, Lewis B, Hutyra C, Olson S. The iliac oblique judet view to assess post-operative healing and evaluate anterior acetabular coverage following bernese periacetabular osteotomy. Duke Orthop J 2020;10:37-42
|How to cite this URL:|
Kollmorgen RC, Lewis B, Hutyra C, Olson S. The iliac oblique judet view to assess post-operative healing and evaluate anterior acetabular coverage following bernese periacetabular osteotomy. Duke Orthop J [serial online] 2020 [cited 2023 Feb 6];10:37-42. Available from: https://www.dukeorthojournal.com/text.asp?2020/10/1/37/316553
| Introduction|| |
Acetabular dysplasia in the skeletally mature patient has gained much attention over the last 30 years. The Bernese periacetabular osteotomy (PAO) has shown to be a reliable procedure to restore femoral head containment, improve function, and decrease pain in patients with acetabular dysplasia.,,,,,, Symptomatic hip dysplasia results from the loss of containment and subsequent instability of the hip, and historically, the center-edge angle (CEA) is used to classify severity of dysplasia with <20° being dysplastic and 20°–25° borderline dysplastic.,, As the field of hip preservation continues to grow, so does the evolution of our ability understand the utility of radiographic measurements.
Radiographically, there are many measurements to define hip dysplasia. The false profile (FP) radiographic view is commonly obtained pre- and post-operatively by hip preservation surgeons to assess anterior femoral head coverage, postoperative anterior correction, and to assess for osteotomy healing.,,,,,,,,,,, Lequesne's Anterior CEA (ACEA) or Vertical-Center-Anterior margin (VCA) is commonly measured on the FP view to determine the anterior coverage of the femoral head.
At our institution, the FP view is routinely used as a preoperative tool. In the postoperative period, the senior author (XYZ) obtains Judet views to monitor osteotomy healing. Our clinical observation is that the iliac oblique (IO) Judet view provides a profile of anterior coverage of the femoral head similar to that of the FP view. The ACEA on the IO Judet view appears to correlate with the FP for the same ACEA measurements. We hypothesized that the postoperative ACEA as measured on FP view would be clinically identical to or clinically significant within ±5° of the ACEA as measured on the IO Judet view.
| Methods|| |
This retrospective study underwent exempt review and obtained approval through the Duke Medicine IRB (Protocol ID: Pro0082887). Charts and radiographs were retrospectively evaluated for 11 post-operative patients whom underwent a Bernese PAO from the senior author's hip preservation clinic from August to December 2016. Cohort size was selected based on previously published studies. Both FP and IO Judet views were obtained postoperatively as part of standard of care to assess healing of the osteotomy. ACEA measurements were recorded on both views by two hip preservation surgeons (***). The FP view was obtained using the method originally described by Lequesne in 1961. To obtain this view, the patient stood with the pelvis rotated 65° relative to the Bucky wall stand, with the foot of the affected hip parallel to the radiographic cassette. The beam was positioned at one meter from the affected hip and coned down to show only the affected hip, [Figure 1]. For the IO Judet views, the method as described by Judet was utilized. The patient was in the supine position, and the beam was positioned at one meter from the pelvis. The pelvis was rotated 45° toward and away from the affected side, and images were taken. Care was taken to assure the tip of the coccyx was centered over the femoral head on the obturator oblique view side. For the ACEA (VCA), the center of the femoral head was estimated using a circle fit to the medial and inferior contour of the femoral head. The diameter of the femoral head was measured, and the center of the head was identified. ACEA was then measured from a vertical reference from the identified femoral head center, perpendicular to the radiograph, and the anterior most aspect of the sourcil was used as the anterior reference for the measurement [Figure 2].,,,
|Figure 1: Coned in false profile view. Images were obtained following the methods of Judet and Lequesne. Circle of best fit demonstrated with Anterior Center Edge Angle, measurement in degrees|
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|Figure 2: Left hip iliac oblique Judet view. Images were obtained following the methods of Judet and Lequesne. Iliac oblique judet view with circle of best fit with Anterior Center Edge Angle, measurement in degrees|
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Two observers, a board certified orthopedic surgeon and hip preservation fellow (***) and independent hip preservation faculty member (***), measured the ACEA on the FP and IO Judet views. To attempt to eliminate recall bias, each observer measured the ACEA for each FP and IO Judet view per patient and repeated for 4 different days, minimum of 24 h apart. All measurements were made within a 2-week period. The order the images were presented and evaluated was reversed per the round of measurements. This methodology provided eight measurements for ACEA for the FP and IO Judet views per patient for a total of 88 FP measurements and 88 IO Judet measurements. Microsoft Excel was utilized for the statistical analysis. Intraclass Correlation Coefficients (ICC) with a 95% Confidence interval (CI) were calculated for intra- and inter-observer reliability and interpreted as: minimal < 0.2, poor 0.2–<0.4, moderate 0.4–<0.6, strong 0.6–≤0.8, and excellent > 0.8. Paired t-tests were performed, utilizing hypothesized SDV of 0°, 1°, 2°, and 3°, between the average measurements per patient for each surgeon with all reported P values two-tailed with an alpha level of 0.05 indicating significance. Bland-Altman plots were utilized to analyze the agreement between the FP and IO Judet view for all observations.
| Results|| |
The mean ACEA for both the FP and IO Judet views is listed in [Table 1] for each observer. The intra-observer reliability for ACEA measurement was excellent: 0.987 and 0.983 for the FP and IO Judet views, respectively. The inter-observer reliability was excellent as well: 0.978 and 0.934 for the FP and IO Judet views, respectively [Table 2].
|Table 2: Intraclass correlation coefficient with a 95% confidence interval|
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The paired t-test with a hypothesized mean difference of zero degrees yielded significant P values, <0.05, in 6/11 measurements, (54%). When computing for a mean difference of 3° all measurements reached significant P values [Table 3].
When comparing the two groups, the mean SDV for the FP group is within ± 2.5° for all observers and for the IO Judet group the SDV is within ± 3.5°. Bland-Altman analysis for agreement between the FP and IO Judet view measurements revealed that 170/176 (96.6%) of measurements were within the upper and lower levels of agreement and 6/176 (3.4%) were outside of agreement [Figure 3].
|Figure 3: Bland Altman Plot is shown for all measurements from both observers for the false profile and iliac oblique Judet view. Data points are plotted difference versus mean|
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| Discussion|| |
The Bernese PAO, popularized by Ganz, has been shown to be a reliable procedure for treating adult dysplasia.,,,,,, Postsurgical healing and correction have traditionally been evaluated and monitored by the AP Pelvis and FP radiographic views. This study introduces Judet views as a method to monitor postoperative column healing following PAO and shows an excellent clinical correlation of the ACEA measurement on both the Judet IO and FP radiographic views. Across the study cohort, ICC, with 95% CI, showed exceptional intra- and inter-observer reliability with values of 0.978 and 0.934 for the FP and Judet IO view, respectively. When comparing the two groups, the SDV was clinically significant within 5° with the FP (±2.5°) and IO Judet (±3.5°) views.
Judet et al. in their landmark article described the 45° three-quarter external oblique (IO) view as a means to evaluate the posterior column and the anterior lip of the acetabulum, providing an initial reference to anterior coverage. Initially, Lequesne described the VCA based on the FP view, and while other authors have further described radiographic techniques to calculate ACEA, none have described this observation on the IO Judet view.,,,,,,,,,,,,, In the trauma literature, references are present to Judet views providing variable measurements, an inconsistency that does not necessarily apply to dysplasia patients treated with a PAO.,, PAO patients are not as painful nor traumatized as a typical pelvic fracture patient and can comfortably assume the proper position for the Judet view radiographs. It is important that the technique for obtaining the Judet views be both accurate and precise to allow for the observed excellent intra-and inter-observer correlations. In the senior author's opinion, the AP pelvis combined with Judet views allows for multiple views of the osteotomy to monitor post-operative healing, and early assessment of anterior correction as the patient's do not need to bear weight for the evaluation. In contrast, the weight-bearing position required for a FP radiographic image and assessment of anterior coverage may not be properly obtained until 4–8 weeks postoperatively.
Consideration to postoperative radiation exposure is also of a concern. The Entry Surface Dose of radiation to obtain an AP pelvis is 3.7 mGy, and for a FP a dose of radiation 1.33 mGy is required to 3.7 mGy for the IO view., As a large proportion of patients undergoing this procedure are young women of childbearing age, decreasing the postoperative radiation exposure by avoiding the FP view would be of benefit.
The excellent intra- and inter-observer reliability was consistent with the literature. Anderson et al. described their technique for obtaining ACEA measurements on the FP view. The study utilized 30 patients, 4 observers measuring the FP view twice per patient per observer, and ACEA measurements were compared utilizing two techniques. The first technique the observer estimated the center of the femoral head versus their described technique of calculating the center of the femoral head as templated the center of a sphere drawn on the congruent articular aspect of the femoral head. This study revealed good inter-observer reliability of 0.55 versus 0.76 comparing standing measurements to the spherical method, and they concluded that not accounting for sphericity leads to lateralization of the femoral head center and underestimating acetabular coverage. Their intra-observer reliability was 0.9 with both techniques. We utilized a similar method to calculate the ACEA on both the FP and IO Judet view and achieved perfect intra-and inter-observer reliability of 0.98 and 0.93–0.98. Our measured ACEA on the IO Judet views showed significance to standard FP views within 3° on all measurements.
Bouttier et al. evaluated AP pelvis and FP radiographs of 60 hips and looked at the reproducibility of commonly measured hip radiographic markers, including ACEA (VCA), utilizing two observers. They found excellent ICC values for all measurements and concluded that the ACEA was a reproducible measurement between observers. Our results showed perfect ICC and Bland-Altman analysis revealed 96% of measurements were within the upper and lower levels of agreement, showing excellent correlation. While our study was not aimed at diagnosing dysplasia, as the Bouttier study did, our finding of perfect intra- and inter-class correlation coefficients demonstrates the IO Judet view as compared to the FP view as a reproducible means to measure the ACEA in postoperative PAO patients.
Lequesne's technique for ACEA measurement on the FP view has also been challenged in the literature. Fabeck et al. attempted to analyze the anatomic landmarks of the acetabulum and correlate to the sourcil for ACEA measurement utilizing Lequesne's technique. 15 hemipelvis were utilized, and the anterior acetabulum was marked with radiodense beads and k-wires and FP radiographs were taken. They measured the anatomic VCA on a FP orientation and compared that to the radiological VCA as measured on a FP view. While the authors concluded that Lequesne's technique does allow for a diagnosis of dysplasia they stress the admitted variability in the measurement of ± 5° and show that the Lequesne's FP radiographic measurement for VCA is not measuring a real anatomic structure. This finding can attest to the variability in measurements reported in the literature, and our findings comparing the ACEA measurement on the FP and IO Judet view. While our study shows perfect intra- and inter-observer reliability, our SDV was ± 2.5° on the FP view and ±3.5° on the IO Judet view, and within the above reported ±5°.
Variability between ACEA measurements, as observed in our study, has been reported by other authors. Milcan et al. studied 102 asymptomatic volunteers, 181 hips included, and measured the ACEA (VCA) on the FP view. The technique described utilized the anterior most aspect of the acetabulum, instead of the anterior most aspect of the sourcil. The mean VCA across all observers was 49.27° ± 7.77°, and they concluded that a VCA angle of <24.7° may be a risk factor for dysplasia and OA of the hip. The authors recognize that their measurement is greater than other studies due to redefining the anterior landmark for measurement. This conclusion was further corroborated by Hansen et al., which set out to compare FP view center edge measurements based on bone or sourcil as the reference point for the anterior edge for the ACEA measurement. They defined clinical significant difference of ±5° difference between the two methods. Inter- and intra-observer agreement was excellent for the ACEA as measured on the FP view. They showed that using the anterior bone on the FP view as a reference led to a 10° greater measurement than the sourcil and stressed that proper methods of what landmarks are used in the evaluation is essential. Our study utilized the sourcil as an anterior landmark for ACEA measurements with two observers showed similar variability but at a much smaller scale of ± 2.5° on the FP view and ± 3.5° on the IO Judet view.
There were several limitations involved in the conduct of this study. First, the study was limited by a small sample size, and while a limitation, our study is in line with previously reported studies on the radiographic parameters in hip preservation.,,,,, Wyatt et al. recently reported on the Femoral-Ephiphyseal Acetabular Roof (FEAR) Index. The study described a new radiographic landmark associated with instability of the hip in patients with borderline dysplasia. The radiographic finding was based on 10 radiographs and two observers, similar to our study design. While a small cohort their methodology yielded significant intra-and inter-observer reliability and established the FEAR index as a means of aiding in the diagnosis of instability in boarderline dysplastic patients. Second, when comparing radiographs where one measurement is taken at 45° (Judet) and the other at 65° (FP View), one would not expect correlation of measurements, but our observation shows statistical correlation between the ACEA as measured on the IO Judet view to the FP views. Several authors have reported poor correlation of VCA to actual anterior coverage as well as lack of anatomic correlation to the measurement and that may explain why the radiographic measurements may correlate.,,,
| Conclusion|| |
In conclusion, this study demonstrates a reproducible and reliable means of monitoring column healing after PAO and allows for an earlier, reproducible, and accurately correlated measurements of the femoral head coverage, as measured by the ACEA on the IO Judet views. Given these findings, we would suggest an index FP view and IO Judet view at the initial consultation and follow the IO view over time, thus avoiding postoperative FP view radiation exposure.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]