How Common Is Femoroacetabular Impingement Morphology in Asymptomatic Adults? A 3D CT-Based Insight into Hidden Risk

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Femoroacetabular impingement (FAI) morphology involves hip joint structural abnormalities that can lead to osteoarthritis.
• FAI morphology is prevalent in both symptomatic and asymptomatic individuals, highlighting the need for early detection.
• Understanding asymptomatic FAI morphology is crucial for preventive strategies and managing joint health.

Purpose of the Study:

• To evaluate the three-dimensional (3D) congruence of hip joint surfaces in asymptomatic individuals.
• To assess FAI morphology and its prevalence in asymptomatic hips using 3D reconstructions.
• To investigate gender and side differences in FAI-related measurements like alpha angle and lateral center-edge angle (LCEA).

Main Methods:

• Retrospective analysis of 86 hip joints using 3D reconstructions from CT scans.
• Utilized Mimics software for creating 3D models from computed tomography data.
• Measured alpha angles and LCEA to identify FAI features in asymptomatic hips.

Main Results:

• Significant gender differences were observed in alpha angles, with males exhibiting higher mean values.
• An alpha angle >50°, indicative of cam-type FAI, was found in 25.6% of right hips and 13.9% of left hips.
• LCEA values did not show significant gender or side differences, averaging 30.21°.

Conclusions:

• A notable proportion of asymptomatic hips, especially in males, display FAI-consistent morphology.
• Cam-type FAI features were often bilateral, while pincer-type morphologies were more sporadic and unilateral.
• Elevated alpha and LCEA measurements in asymptomatic individuals suggest subclinical FAI may not always signify disease, requiring longitudinal studies.