Generalized Joint Hypermobility Is Associated With Decreased Hip Labrum Width: A Magnetic Resonance Imaging-Based Study.

PURPOSE

To explore the relationship between generalized joint hypermobility and hip labrum width.

METHODS

A retrospective review was performed of a single-surgeon database containing patients who underwent hip arthroscopy between 2014 and 2017. Patients were assessed for generalized laxity via Beighton Test Scoring (BTS), which tests for hyperextension of the fifth metacarpophalangeal joint, thumb apposition, elbow hyperextension, knee hyperextension, and trunk flexion on a 9-point scale. Patients were stratified into a "high BTS cohort" with a BTS ≥4, and a control cohort with BTS <4. Magnetic resonance imaging measurements of labral width for each patient were conducted by 2 blinded, musculoskeletal fellowship-trained radiologists at standardized "clockface" locations using a previously validated technique. Statistical analyses used to determine associations between BTS and labral width included Mann-Whitney and Fisher exact testing as well as linear regression.

RESULTS

Thirty-four patients met inclusion criteria (17 cases, 17 controls). Both groups were composed exclusively of female patients. There was no significant difference between cases or controls in terms of age (33.3 ± 10.4 years vs 35.2 ± 8.3 years,  = .57) or body mass index (26.1 ± 9.3 vs 23.6 ± 3.4,  = .36). The high Beighton score cohort had significantly thinner labrae at the indirect rectus (5.35 ± 1.2 mm vs 7.1 ± 1.1 mm, < .001) and anterosuperior position (5.53 ± 1.4 mm vs 7.27 ± 1.6 mm,  = .003). There was no statistical difference between the high Beighton score cohort and controls at the psoas U position (6.47 ± 1.6 mm vs 7.43 ± 1.7 mm,  = .112). Linear regression analysis demonstrated Beighton score was significantly negatively associated with labrum width at the indirect rectus position (R = 0.33, < .001) and the anterosuperior position (R = 0.25,  = .004).

CONCLUSIONS

Patients with a BTS ≥4 were found to have significantly thinner labra than those with a BTS of <4.

LEVEL OF EVIDENCE

III, retrospective comparative trial.