Labral tears with axial plane disorders

Abstract

Objectives: This study aims to determine if there is an axial plane coverage insufficiency in patients with symptomatic labral tears compared to the contralateral asymptomatic side and healthy control subjects.

Patients and methods: This retrospective study was conducted between December 2017 and January 2019. Thirty patients (21 males, 9 females; mean age 28 years; range, 20 to 36 years) operated due to unilateral symptomatic acetabular labral tears secondary to femoroacetabular impingement were evaluated. Twenty asymptomatic patients (13 males, 7 females; mean age 27±9 years; range, 19 to 36 years) were included in the control group. The relationship between acetabular morphology and labral tear was investigated with the comparison of unilateral symptomatic hips with contralateral asymptomatic hips and the control group by using radiological parameters on plain radiographs and computed tomography.

Results: When the patient group symptomatic side was compared to the control group, acetabular anteversion angle (A A A) and alpha (α) angle were higher, while posterior acetabular sector angle and horizontal acetabular sector angle were lower. When the asymptomatic side was compared to the control group, AAA was higher in the patient group. There was no difference between the symptomatic and asymptomatic sides in the patient group; the symptomatic side yielded a higher α; angle.

Conclusion: Posterior axial plane coverage deficiency in combination with cam deformity (increased α angle) seems to play a role in the pathogenesis of symptomatic acetabular labral tears, even creating a side-to-side difference in some individuals.

Figure 1. Measurement of acetabular anteversion on computed tomography. Acetabular anteversion angle is measured as angle between a line between anterior and posterior acetabular ridge (line b) and a reference line (line c) drawn perpendicular to a line between posterior pelvic margins at level of sciatic notch (line a).

Figure 2. Measurement of anterior acetabular sector angle (angle between anterior acetabular margin, center of femoral head, and intercapital center line) and posterior acetabular sector angle (angle between posterior acetabular margin, center of femoral head, and intercapital center line). AASA: Anterior acetabular sector angle; PASA: Posterior acetabular sector angle.