The association between cam morphology and hip pain in males and females within 10 years: A national prospective cohort study (CHECK).

Objectives: To determine the association between baseline cam morphology and self-reported hip pain assessed at annual visits over a 10-year follow-up period stratified by biological sex. The secondary aim was to study the association between the magnitude of cam morphology and the severity of pain in symptomatic hips.

Methods: The nationwide prospective Cohort Hip and Cohort Knee (CHECK) study includes 1,002 participants aged 45-65 years. Logistic regression with generalized estimating equations were used to determine the strength of the associations between (1) baseline cam morphology (both alpha angle ≥60° and as a continuous measure) and the presence of hip pain at 10 annual follow-up visits and (2) the alpha angle (continuous) and the severity of pain as classified by Numerical Rating Scale at 5-,8-, 9-, and 10-years. The results are expressed as odds ratios (OR), adjusted for age, biological sex (only in the sex-combined group), body mass index, and follow-up Kellgren and Lawrence grade.

Results: In total, 1,658 hips were included at baseline (1,335 female hips (79.2%)). The prevalence of cam morphology was 11.1% among all hips (29.1% in males; 6.4% in females). No association was found between cam morphology at baseline and the presence of hip pain at any follow-up in the female or sex-combined group. In males, only at 5-year follow-up, significant adjusted ORs were observed for the presence of cam morphology (1.77 (95%CI: 1.01-3.09)) and the alpha angle (1.02 (95%CI:1.00-1.04)). No evidence of associations was found between the alpha angle and the severity of hip pain in any of three groups.

Conclusion: Within this study, no consistent associations were found between cam morphology and hip pain at multiple follow-ups. There might be a weak relationship between cam morphology and hip pain in males, while no such relation was found in females. We did not identify an association between the alpha angle and severity of hip pain.