Prevalence of Pincer Morphology in Early Adolescents From the General Population: A Population-Based Study

Objective: 

Pincer morphology can lead to femoroacetabular impingement syndrome (FAIS) and may be a modifiable risk factor for hip osteoarthritis (OA). Currently, no studies investigate the prevalence of pincer morphology in early adolescence, which is the period when this bony shape likely develops. The purpose of this study was to estimate the prevalence and birth-assigned sex distribution of pincer morphology in early adolescents from the general population in the Netherlands. 

Methods: 

This study was embedded in the Generation R Study, a population-based prospective cohort in Rotterdam, the Netherlands. Around the age of 13 years, participants underwent high-resolution dual-energy x-ray absorptiometry of their full-body and right hip. The lateral center edge angle (LCEA) was automatically determined based on landmarks outlining the hip contour, and pincer morphology was defined as a LCEA ≥ 40°. The overall and birth-assigned sex-specific prevalence was presented as a percentage with 95% confidence interval (CI). 

Results: 

A total of 3,986 adolescents (median age 13.5 years [2.5th–97.5th percentile: 13.2–14.6]; 46.8% male) were included. The overall prevalence of pincer morphology was 3.1% (95% CI 2.6–3.6). The prevalence in male and female adolescents was 3.0% (95% CI 2.2–3.7) and 3.3% (95% CI 2.5–4.0), respectively. 

Conclusion: 

Among early adolescents from the general population in the Netherlands, the estimated prevalence of pincer morphology was 3.1%. Male and female adolescents had a similar prevalence of pincer morphology. These findings could inform the timing of prevention strategies for pincer morphology and potentially reduce the risk of FAIS and hip OA.