Generalized Joint Hypermobility Is Predictive of Hip Capsular Thickness

Area of Science:

• Orthopedics
• Sports Medicine
• Biomechanics

Background:

• Hip microinstability pathomechanics are not well-defined.
• Potential contributing factors include anatomical abnormalities, repetitive hip forces, and ligamentous laxity.

Purpose of the Study:

• To investigate the relationship between generalized joint hypermobility (GJH) and hip capsular thickness.
• To test the hypothesis that GJH predicts a thinner hip capsule.

Main Methods:

• Prospective study of 100 patients undergoing hip arthroscopy for hip pain.
• Assessed generalized joint hypermobility using the Beighton test score (BTS; ≥4 defined as hypermobile).
• Measured hip capsular thickness arthroscopically at the anterior portal; recorded ligamentum teres (LT) pathology.

Main Results:

• A significant association was found between BTS and capsular thickness.
• BTS <4 predicted capsular thickness ≥10 mm; BTS ≥4 correlated with capsular thickness <10 mm.
• Higher incidence of LT tears in patients with thinner capsules (≤7.5 mm) and higher BTS (≥4).

Conclusions:

• Generalized joint hypermobility is a highly predictive measure of hip capsular thickness.
• Beighton test score effectively differentiates between thicker and thinner hip capsules.
• Findings may inform understanding of hip instability and associated pathologies like LT tears.