Patients With Generalized Joint Hypermobility Have Thinner Superior Hip Capsules and Greater Hip Internal Rotation on...

Area of Science:

• Orthopedics
• Radiology
• Human Anatomy

Background:

• Femoroacetabular impingement syndrome (FAIS) is a common cause of hip pain.
• Joint hypermobility may influence hip biomechanics and morphology.
• Understanding these relationships is crucial for diagnosis and treatment.

Purpose of the Study:

• To compare hip range of motion (ROM), capsular thickness (MRI), and bony morphology (radiographs/CT) between patients with and without joint hypermobility (Beighton Test score - BTS).
• To analyze differences based on sex and age.

Main Methods:

• Retrospective review of patients undergoing hip arthroscopy for FAIS.
• Data collected included BTS, hip ROM, demographics, and imaging findings (capsular thickness, bony morphology).
• Statistical analyses, including multivariable regression, controlled for BTS, age, and sex.

Main Results:

• Forty percent of patients had a BTS ≥4; females and younger patients were more likely to have higher BTS.
• Male patients had thicker superior capsules.
• Patients with BTS ≥4 exhibited greater femoral version, McKibben index, and significantly increased hip internal rotation across various positions.

Conclusions:

• Hypermobility (BTS ≥4) is associated with greater hip internal rotation and specific bony morphology.
• Sex differences in capsular thickness and bony morphology contribute to variations in ROM.
• These findings highlight the interplay between hypermobility, anatomy, and hip joint mechanics in FAIS.