Prevalence of Radiographic Morphology of Femoroacetabular Impingement in Indian Population: A Multicenter Study

Prevalence of Morphological Variations Associated With Femoroacetabular Impingement According to Age and Sex: A Study of 1878 Asymptomatic Hips in Nonprofessional Athletes

Background:

Radiographic findings related to the cam and pincer variants of femoroacetabular impingement (FAI) include measurements of the alpha angle and lateral center-edge angle (LCEA). The function of these radiographic findings has been put into question because of high heterogeneity in reported studies.

Purpose:

The aim of this study was 3-fold: (1) to determine the prevalence of cam and pincer variants according to sex and age on anteroposterior (AP) pelvic radiographs from an asymptomatic nonathletic population, (2) to identify the most common radiographic signs of cam- and pincer-type variants, and (3) to determine if there are variations in the prevalence of these radiographic signs according to sex and age.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

There were 3 independent observers who retrospectively analyzed the 939 AP pelvic radiographs (1878 hips) of patients aged 18 to 50 years who did not have hip symptoms and who were not professional athletes. The prevalence of the cam and pincer variants according to the alpha angle and LCEA, respectively, and the presence of other radiographic signs commonly associated with these variables were determined in the overall population and by subgroup according to sex and age group (18-30, 31-40, and 41-50 years). Descriptive and inferential statistics were used to analyze the study sample.

Results:

The mean age of the included population was 31.0 ± 9.2 years, and 68.2% were male. The prevalence of the cam-type variant was 29.7% (558/1878), and that of the pincer-type variant was 24.3% (456/1878). The radiographic signs that were most associated with the cam and pincer variants were a pistol-grip deformity and the crossover sign, respectively. Significant differences (P < .001) in the prevalence of these variants were identified between men and women in both variants. No differences were observed in the alpha angle or LCEA according to sex or age.

Conclusion:

Radiographic findings suggestive of FAI had significant variations with respect to sex and age in this study sample. This study provides information to determine the prevalence of these anatomic variants in the general population.

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.