Determination of correlation between alpha angle and herniation pit in healthy adults on hip MRI

Abstract

The purpose of this study was to investigate the association between alpha angle and herniation pit (HP) in healthy adults on hip magnetic resonance imaging (MRI). Between May 2016 and September 2018, 502 hip joint MRIs of 251 healthy adults (aged between 19 and 82 years) were retrospectively evaluated to determine the presence of HP of the femoral neck. Femoral neck alpha angles were also measured. Possible relationships between herniation pit and age, sex, sided-ness, and alpha angle were investigated. One hundred twenty-four males and 127 females were included, and the mean age was 40.96 ± 12.85. HPs were present in 20 of the 502 hips, a prevalence of 3.98 % (45 % at right and 55 % left hips). The herniation pit sizes were ranged from 2 to 9.6 mm; the average value was 5.1±2.2 mm. The average value of the alpha angle of 502 hips was 50.42 ± 5.91°. The alpha angle was ≥ 55 degrees in sixty-seven (13.35 %) of 502 patients. No correlation was found between herniation pit and age, sex, side (right or left hip) and alpha angle degrees. No statistically significant association was found between alpha angle ≥ 55 degrees and the actual size of the herniation pit. There is no correlation between age, sex, or alpha angle ≥ 55 degrees and the prevalence of herniation pit in healthy hips. HP formation is an incidental radiologic finding and unrelated to the alpha angle.