Does Labral Size Correlate With Degree of Acetabular Dysplasia?

Background: Hip dysplasia has been shown to be a cause of early arthritis. The decrease in bony coverage has shown increased stress on the acetabular labrum as it shares an increased load. Purpose/Hypothesis: The purpose of this study was to divide a cohort of patients by radiographic measures of dysplastic and nondysplastic hips for comparison with regard to labral size at 4 anatomic locations. The hypothesis was that dysplastic hips will have significantly larger labral size compared with nondysplastic hips. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A prospective study was conducted at a single institution. A total of 130 patients underwent hip arthroscopy during the study period from September 2011 to February 2012. Intraoperatively, arthroscopic measurements were taken at 4 quadrants on the acetabular clockface: anterosuperior (12-3 o'clock), anteroinferior (3-6 o'clock), posterosuperior (9-12 o'clock), and posteroinferior (6-9 o'clock). Three radiographic parameters for dysplasia were used to substratify the study population base: lateral center-edge angle (LCEA) <= 25 degrees and LCEA >25 degrees, acetabular inclination (AI) <= 10 degrees and AI >10 degrees, and anterior center-edge angle (ACEA) <= 20 degrees and ACEA >20 degrees. Results: For the LCEA <= 25 degrees group, there were 28 hips with mean LCEA of 20.96 degrees +/- 3.40 degrees. Patients with LCEA <= 25 degrees had larger labral width in all 4 quadrants (P<.05). For AI >10 degrees, there were 12 hips with the mean AI 12.92 degrees +/- 2.50 degrees. Patients with AI >10 degrees had larger labral size in the posteroinferior quadrant only (P<.05). For ACEA <= 20 degrees, there were 4 hips with a mean ACEA of 11.25 degrees +/- 5.19 degrees. The anteroinferior and posteroinferior quadrants had a significant increase in labral size when substratified by ACEA <= 20 degrees (P<.05). Conclusion: Labral size was significantly larger in dysplastic hips compared with nondysplastic hips. The posteroinferior quadrant labrum was larger in size in dysplastic hips, as measured by any of the 3 radiographic measurements of dysplasia. Hips with LCEA <= 25 degrees had larger labra in all 4 quadrants.