The online version of this article (doi:10.1186/s12891-015-0791-z) contains supplementary material, which is available to authorized users.
The authors declare that they have no competing interests.
HT performed the subject selection, image analysis and statistical analysis, interpreted the results and drafted the manuscript. KW performed the image analysis, interpreted the results and revised the manuscript. IO provided advice on the image analysis and prepared the corresponding parts of the manuscript. MS provided advice on the statistical analysis and prepared the corresponding parts of the manuscript. YTK provided advice on the research planning, interpreted the results and revised the manuscript. HO supervised the research and completed the final manuscript. HA found focal concavity of posterior superior acetabulum, directed the research and revised the manuscript. All authors read and approved the final manuscript.
Although little is known, a limited number of three-dimensional computed tomography (CT) images of the pelvis present focal concavity of posterior superior acetabulum. The purpose of the present study was to investigate this morphologic deformity and its relation with dysplasia and retroversion in adults who were expected to have the original morphology of the acetabulum after growth.
Consecutive adult patients with hip pain who visited our hospital and had three-dimensional pelvic CT images were retrospectively analyzed after approval of the institutional review board; exclusion criterions included diseases, injuries and operations that affect the morphology of the hip including radiographic osteoarthritis Tönnis grades 2 and 3. Focal concavity of posterior superior acetabulum was evaluated by three-dimensional CT image. Acetabular dysplasia was determined by lateral center edge (LCE) angle <25°, Tönnis angle >10°, and anterior center edge (ACE) angle <25° on standing hip radiographs. Acetabular version angle was measured at the one-fourth cranial level of axial CT image. A subgroup analysis included only younger adult patients up to 50 years.
The subjects analyzed were 46 men (92 hips) and 54 women (108 hips) with a median age of 57.5 (21–79) and 51.0 (26–77) years, respectively. Focal concavity of posterior superior acetabulum was observed in 13 hips; 7 patients had unilaterally, while 3 patients showed bilaterally. Among these hips, pain was observed in 8 hips but 4 hips (2 patients) were associated with injuries. This morphologic abnormality was not associated with acetabular dysplasia determined by LCE angle <25°, Tönnis angle >10° or ACE angle <25°. Of note, no acetabulum with the deformity plus dysplasia was retroverted. These findings were confirmed in a subgroup analysis including 22 men (44 hips) and 27 women (54 hips) with a median age of 31.0 (21–50) and 41.0 (26–50) years, respectively.
Focal concavity of posterior superior acetabulum could be a rare morphologic abnormality of acetabular formation independent of lateral or anterior dysplasia or retroversion.
Additional file 1: Figure S1. Axial, coronal and sagittal two-dimensional pelvic CT images in a 52-year-old woman, showing focal concavity of posterior superior acetabulum as indicated by arrows. These images were from the same patient as the image in Figure 1. (TIFF 463 kb)
Additional file 2: Table S1. Inter-rater reliability between two readers. (DOCX 21 kb)12891_2015_791_MOESM2_ESM.docx
Additional file 3: Figure S2. Inter-rater reliability between two readers of lateral center edge angle, Tönnis angle, anterior center edge angle, and acetabular version angle in all subjects. (TIFF 42 kb)12891_2015_791_MOESM3_ESM.tif
Additional file 4: Figure S3. Inter-rater reliability between two readers of lateral center edge angle, Tönnis angle, anterior center edge angle, and acetabular version angle in subjects at 50 years or younger. (TIFF 42 kb)12891_2015_791_MOESM4_ESM.tif
Additional file 5: Figure S4. A posterior view of three-dimensional pelvic CT image in all subjects at 50 years or younger with focal concavity of posterior superior acetabulum as indicated by arrows. (TIFF 406 kb)12891_2015_791_MOESM5_ESM.tif
Additional file 6: Figure S5. A posterior view of three-dimensional pelvic CT image in all subjects at 51 years or older with focal concavity of posterior superior acetabulum as indicated by arrows. (TIFF 443 kb)12891_2015_791_MOESM6_ESM.tif
Additional file 7: Figure S6. A posterior view of the representative three-dimensional pelvic CT image during growth, showing the fusion site between ilium and ischium. (TIFF 157 kb)12891_2015_791_MOESM7_ESM.tif
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- Focal concavity of posterior superior acetabulum and its relation with acetabular dysplasia and retroversion in adults without advanced hip osteoarthritis
Yoon Taek Kim
- BioMed Central
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