Radiographic findings of patients with femoroacetabular impingement can vary significantly depending on the patient’s age and sex, researchers find.
Femoroacetabular Impingement by Age, Sex
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Secondary#femoroacetabularimpingement#camvariants#pincervariants
“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,” they wrote.
In the study, “Prevalence of Morphological Variations Associated With Femoracetabular Impingement According to Age and Sex: A Study of 187 Asymptomatic Hips in Nonprofessional Athletes”, they determined the most common radiographic signs of cam-pincer type variants. The findings were published on February 5, 2021 in the Orthopaedic Journal of Sports Medicine.
Three independent observers who retrospectively analyzed the 939 anteroposterior pelvic radiographs (1878 hips) of patients aged 18 to 50 years who didn’t have hip symptoms and who weren’t professional athletes. Mean age of patients was 31.0±9.2 years and 68.2% were male.
The observers determined the prevalence of the cam and pincer variants, according to the alpha angle and lateral center-edge angle and the presence of other radiographic signs commonly associated with these variables.
According to the data, the prevalence of the cam-type variant was 29.7% (558/1878), and that of the pincer-type variant was 24.3% (456/1878).
Overall, the radiographic signs most associated with the cam and pincer variants were a pistol-grip deformity and the crossover sign, respectively. There were significant differences in the prevalence of these variants between men and women in both variants. However, there were no differences in the alpha angle or LCEA according to sex or age.
“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,” they wrote.
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This is a fascinating development. In my practice we've seen similar outcomes with the revised protocol. The key differentiator seems to be patient selection criteria. Has anyone else noticed the correlation with BMI thresholds?
Great point. I'd push back slightly on the conclusion, the sample size in the cited study is too small to draw population-level inferences. That said, the directional signal is compelling and worth a larger RCT.
We implemented a similar approach last year. Early results are promising but we're still gathering 12-month follow-up data. Happy to share our protocol if anyone is interested.
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