Acetabular morphometry and prevalence of hip dysplasia in the South Asian population

The determination of acetabular parameters in a Turkish population sample: CT-based retrospective analysis of side and gender differences

Determination of the acetabular morphology and orientation is important for the total hip arthroplasty applications. In general, preoperative planning for these patients is done on true hip X-rays in orthopedics clinics. But those evaluations may not represent the acetabular architecture in detail, because of 2 dimensional images. The aim of this study is to determine the acetabular morphology of a healthy Turkish adult population sample through examination of acetabular parameters on 3-dimensional computed tomography (CT)-based images according to side and gender. A retrospective evaluation was made of acetabulum CT scans taken for various reasons in a healthy Turkish population sample. The examination parameters were defined as measurements of the acetabular anteversion angle, acetabular abduction angle, lateral center edge angle, acetabular width, acetabular depth, sagittal acetabular angle, and medial wall thickness values. The CT scans including the bone structure were examined of a total of 252 hips of 126 patients. The acetabular index was calculated as depth/width × 100. Lateral center edge angle of < 20° with medial wall thickness > 5 mm was accepted as a criterion of dysplasia of the acetabulum. Evaluation was made of the acetabular CT scans of 73 females and 53 males with a mean age of 44.64 ± 12.31 (19-68) years. A statistically significant difference was determined between the sides in respect of acetabular anteversion angle (P = .007) and between the genders in respect of acetabular depth and acetabular width (P = .001, P = .001). The prevalence of dysplasia was determined to be 1.6% for the whole study group, as 1.9% in males and 1.4% in females. In the current study sample there were parametric differences between sides and genders in terms of acetabulum morphology and orientation. Further studies of larger series will be able to provide a better representation of the Turkish population.

Morphometric study of acetabular depth and coverage and their clinical importance

OBJECTIVES

To measure acetabular parameters and to compare parameters of acetabulum between men and women, and right and left sides.

METHODS

The study was conducted in PNS Shifa Hospital, Karachi from January to June 2021. Anteroposterior radiographs of both hips of 70 adults aged 20-70 years were included. The study consisted of 35 men and an equal number of women. We measured acetabular depth, femoral head coverage, acetabular inclination and acetabular depth and width. The acetabular depth was measured using Wiberg's central edge (CE) angle and Sharp angle techniques. Femoral head coverage was determined using measurements between medial edge of hip joint space, lateral edge of acetabulum and femoral head. To determine acetabular inclination, Tönnis angle was measured. Acetabular depth & width ratio (ADR) was evaluated by dividing acetabular width by depth, and multiplying by 100.

RESULTS

There was significant increase in Sharp angle and Tonnis angle in females on the left side as compared to males. Wiberg's central edge angle and acetabular width to depth ratio showed insignificant increase in males as compared to females, whereas values of femoral head coverage were insignificantly more in women.

CONCLUSION

The acetabular parameters were insignificantly different in gender and between right and left sides, although mean values were within normal range. The larger ADR ratio in men was most likely due to increased body weight in them as compared to women.

Joint disease-specificity at the regulatory base-pair level

Given the pleiotropic nature of coding sequences and that many loci exhibit multiple disease associations, it is within non-coding sequence that disease-specificity likely exists. Here, we focus on joint disorders, finding among replicated loci, that GDF5 exhibits over twenty distinct associations, and we identify causal variants for two of its strongest associations, hip dysplasia and knee osteoarthritis. By mapping regulatory regions in joint chondrocytes, we pinpoint two variants (rs4911178; rs6060369), on the same risk haplotype, which reside in anatomical site-specific enhancers. We show that both variants have clinical relevance, impacting disease by altering morphology. By modeling each variant in humanized mice, we observe joint-specific response, correlating with GDF5 expression. Thus, we uncouple separate regulatory variants on a common risk haplotype that cause joint-specific disease. By broadening our perspective, we finally find that patterns of modularity at GDF5 are also found at over three-quarters of loci with multiple GWAS disease associations.

CT Based Analysis of Acetabular Morphology in Northern Indian Population: A Retrospective Study

PURPOSE

The acetabular morphology has shown to differ among different regions of the world. Multiplanar evaluation by computed tomography (CT) scan is the key to assess acetabular depth, version, and inclination at the same time which have been rarely explored before in the Indian population. We present an anthropometric study of the native acetabulum by CT based coronal, sagittal, and axial parameters in the Northern Indian population.

METHODS

The acetabular anteversion (AA), acetabular angle of sharp (AAS), sagittal acetabular angle (SAA), lateral center edge angle (LCEA), acetabular depth (AD), acetabular horizontal offset (AHO), extrusion index (EI) and acetabular depth ratio (ADR) was measured in CT scans of 122 patients (244 hips) without any bony pathologies. LCEA < 20°, ADR < 250, AD < 9 mm, AAS > 43°, and EI ≥ 25% were taken as criteria for dysplastic acetabulum.

RESULTS

There were 62 males and 60 females included in the study with a mean age of 63.8 ± 17.2 years (21-98 years). In this study, females were having significantly lower ADR (p = 0.002) and higher EI (p = 0.01) than males. The prevalence of dysplasia was 3.2% according to LCEA and 1.6% while combining all of the criteria.

CONCLUSION

There are prominent differences in acetabular depth in the Indian population compared with the population of Western countries or other parts of Asia. Females were shown to have shallower acetabulum than males. The comparative analysis of radiographic parameters obtained from our study with the data available on different country-based studies can help better understanding the acetabular morphology of Indian as well as the worldwide population.

LEVEL OF STUDY

Retrospective cross-sectional study.

Prevalence of radiologic acetabular dysplasia in asymptomatic Asian volunteers

The purpose of this study was to evaluate the prevalence of acetabular dysplasia in an asymptomatic Asian population as one of the most important risk factors of hip osteoarthritis. From December 2014 to March 2015, we investigated the data of 200 asymptomatic volunteers (400 hips) aged 18–50 years recruited from our institution. Pelvic radiographs were taken and reviewed by two experienced orthopaedic surgeons. Lateral centre-edge (LCE) angle, Sharp angle, Tonnis angle and acetabular depth-to-width ratio (AD/WR) were measured. We investigated the mean values and identified the statistical differences between the sexes and evaluated the prevalence and bilaterality of acetabular dysplasia defined by each parameter. Mean LCE angle, Sharp angle, Tonnis angle and AD/WR were 26.2°, 41.3°, 8.5° and 0.28, respectively. All parameters showed more dysplastic results in females than in males and were statistically significantly different, except for AD/WR. When defined acetabular dysplasia as LCE angle <20°, Sharp angle >45°, Tonnis angle >14° or AD/WR <0.25, the prevalence of acetabular dysplasia by each parameter was 15.0%, 12.8%, 13.3% and 12.8%, respectively. There was a higher prevalence in females than in males; however, only Sharp and Tonnis angles showed significant differences. The bilaterality of acetabular dysplasia was 18.6–39.5% for all subjects. There is high prevalence of asymptomatic dysplastic hips in the Asian population.

Upsloping lateral sourcil: a radiographic finding of hip instability

While radiographic findings of frank hip dysplasia are well defined, there is a lack of diagnostic criteria for patients with radiographically ‘normal’ hips who have borderline morphologic deficits and clinical instability. In this study, we aim to define and validate a new radiographic finding associated with hip instability known as the upsloping lateral sourcil (ULS). Patients (316) were reviewed for lateral center edge angles, generalized joint laxity assessed with the Beighton Hypermobility Score and the presence of the ULS. The ULS was defined as a caudal-to-cranial inclination of the middle-to-far lateral aspect of the acetabular sourcil with loss of the normal lateral acetabular concavity. The prevalence of the ULS correspondingly increased with the degree of under-coverage as defined by LCEA. Within the normal coverage group, hips with a ULS had smaller LCEAs than those without ULS (29° versus 32°, P < 0.001). Among hips with a ULS, 59.00% had generalized joint laxity. The association between the ULS finding and generalized joint laxity was statistically significant (P < 0.01). The ULS is seen with higher prevalence in patients with clinical hip laxity and radiographically decreasing LCEA and may serve as an adjunctive finding in patients presenting with hip pain and instability. The ULS may help to characterize patients with borderline hip dysplasia and laxity that fall outside conventional imaging criteria for dysplasia.

What Are the Reference Values and Associated Factors for Center-edge Angle and Alpha Angle? A Population-based Study

BACKGROUND

The available evidence regarding normal ranges for the center-edge angle and the alpha angle derives from a few small studies, and associated factors such as sex and anthropometric factors have not been well evaluated. Knowing more about normal values for these parameters is critical, because this can inform decisions about when to perform elective hip preservation surgery. Population-level studies would provide considerable clarity on these issues, but to our knowledge, no such studies are available.

QUESTIONS/PURPOSES

The purposes of this study were (1) to use MRI in patients of a population-based study to establish normal values for the alpha and center-edge angles in the normal adult hip; and (2) to determine whether age, sex, or anthropometric variables were associated with differences in these values.

METHODS

We used MRI images (1.5 T) of 3226 participants of the Study of Health in Pomerania (SHIP). SHIP is a population-based study that started with 4308 participants in 1997. Participants were recruited randomly from official inhabitant data files as a stratified cluster sample of the population from a defined region in northeastern Germany. To ensure a representative epidemiologic cohort, stratification variables were sex, age, and city of residence. Between 2008 and 2012, 1094 of these participants underwent whole-body MRI with pelvic sequences in the second followup. In parallel, the next cohort, SHIP-Trend, started with the same protocol in which 2132 participants underwent MRI examination. Reference values were calculated by quantile regressions for the 2.5 and 97.5 percentiles. Associations with the demographic features sex, age, weight, height, body mass index (BMI), and waist circumference were analyzed by bivariate linear regression models.

RESULTS

The mean center-edge angle was 31° (± 7°) with a corresponding calculated normal range of 17° to 45°. The mean alpha angle was 55° (± 8°) with a corresponding calculated normal range between 39° and 71°. Men (30° ± 7°) had a lower center-edge angle than women (32° ± 8°) (p < 0.001, β = 1.4°; 95% confidence interval [CI], 0.9°-1.9°) and a higher alpha angle (57° ± 8° versus 52° ± 7°, p < 0.001, β = 5.7°; 95% CI, 5.2°-6.3°). Moreover, a higher center-edge angle for the left side was found (33° ± 8° versus 30° ± 8°, p < 0.001, β =3.2°; 95% CI, 3.0°-3.4°). In addition to sex, we found that age, height, waist circumference, and BMI affected both center-edge angle and alpha angle. Weight was associated with the alpha angle as well. Because of these associations, age- and sex-adjusted reference values with belonging formulas were calculated.

CONCLUSIONS

The range of normal center-edge and alpha angles is quite wide. Therefore, only markedly abnormal angles may be associated with pathology. Moreover, center-edge angle and alpha angle are associated with age, sex, and anthropometric factors, which have to be taken into account for better interpretation.

CLINICAL RELEVANCE

The association of abnormal radiographic values with true clinical hip pathology is tenuous at best. Assuming that a patient with an abnormal radiograph requires treatment is unwise. The clinical picture has to be substantial for therapeutic decisions.

Three-dimensional computed tomography reconstruction measurements of acetabulum in Chinese adults

The present study was designed to define the morphological dimensions of the acetabulum in normal Chinese adults and to statistically compare these data with the available data worldwide. This information is important for the diagnosis of dysplasia and treatment of total hip arthroplasty. In this study, the gender and bilateral differences were evaluated. One-hundred CT scans of patients were retrospectively studied. These individuals showed no signs of developmental disturbances in either of the hip joints. Thirty-five morphometric parameters of the acetabulum were measured. The size of acetabulum was evaluated by the acetabular perimeter, anteroposterior diameter, vertical diameter, the depth and width of fossa ovalis in both transaxial and coronal plane. The parameters of acetabular orientation were the acetabular angle, anterior center edge angle, neck shaft angle, acetabular anteversion, and abduction angle. The coverage of acetabulum was examined as the, acetabular head index, center edge angle, the distance between the femoral head, and acetabulum. Gender and bilateral differences were analyzed for each parameter, and compared with available worldwide data. The results showed statistically significant differences between the Chinese genders and also between the Chinese and other human races in some parameters. In conclusion, gender, bilateral and racial differences exist in the morphology of acetabulum. The data may be helpful for the design of total hip arthroplasty for the Chinese population.