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.
NPitt MJ, Graham AR, Shipman JH, Birkby W. Herniation pits of the femoral neck. AJR Am J Roentgenol.1982;138:1115-21.
Leunig M, Beck M, Kalhor M, Kim YJ, Werlen S, Ganz R. Fibrocystic changes at anterosuperior femoral neck: prevalence in hips with femoroacetabular impingement. Radiology. 2005;236:237-46.
Gao ZH, Liu JH, Meng QF, et al. The study of imageology on herniation pit of the femoral neck. Zhonghua Fang She Xue Za Zhi. 2005;39:531-4.
Pfirrmann CWA, Mengiardi B, Dora C, et al. Cam and pincer femoroacetabular impingement: characteristic MR arthrographic findings in 50 patients. Radiology. 2006;240:778-85.
Kassarjian A, Yoon LS, Belzile E, et al. Triad of MR arthrographic findings in patients with cam-type femoroacetabular impingement. Radiology. 2006;236:588-92.
Sundberg TP, Toomayan GA, Major NM. Evaluation of the acetabular labrum at 3.0-T MR imaging compared with 1.5-T MR arthrography: preliminary experience. Radiology. 2006;238:706-11.
Panzer S, Augat P, Scheidler J. Herniation pits and their renaissance in association with femoroacetabular impingement. Rofo. 2010;182:565-72.
Ganz R, Parvizi J, Beck M, et al. Femoroacetabular impingement: a cause for osteoarthritis of the hip. Clin Orthop Relat Res. 2003;417:112-20.
Nötzli HP, Wyss TF, Stoecklin CH, et al. The contour of the femoral headneck junction as a predictor for the risk of anterior impingement. J Bone Joint Surg Br. 2002;84:556-60.
10. Kalçanın manyetik rezonans artrografisi ve femoroasetabular sıkışma. Trd Sem. 2016;4:391-405.
11. Tannast M, Kubiak-Langer M, Langlotz F, et al. Noninvazive threedimensional assessment of femoroacetabular impingement. J Orthop Res. 2007;25:122-31.
12. Pfirrmann CW, Duc SR, Zanetti M, et al. MR arthrography of acetabular cartilage delamination in femoroacetabular cam impingement. Radiology. 2008;249:236-41.
13. Anderson SE, Siebenrock KA, Tannast M. Femoroacetabular impingement. Eur J Radiol. 2012;81:3740-4.
14. Beaulé PE, Zaragoza E, Motamedi K, Copelan N, Dorey FJ. Three-dimensional computed tomography of the hip in the assessment of femoroacetabular impingement. J Orthop Res. 2005; 23:1286-1292.
15. Panzer S, Augat P, Esch U. CT assessment of herniation pits: prevalence, characteristics, and potential association with morphological predictors of femoroacetabular impingement. Eur Radiol. 2008;18:1869-75.
16. Guo Z, Xu L, Su YB, et al. Correlation between the prevalence of herniation pits and the α angle of the hip: computed tomography evaluation in healthy Chinese adults. BMC Musculoskelet Disord. 2013;14:288.
17. Kim JA, Park JS, Jin W, et al. Herniation pits in the femoral neck: a radiographic indicator of femoroacetabular impingement? Skeletal Radiol. 2011;40:167-72.
18. Daenen B, Preidler KW, Padmanabhan S, et al. Symptomatic herniation pits of the femoral neck. AJR Am J Roentgenol. 1997;168:149-53.
19. Hedvabny Z, Zidkova H,Kofranek I. Herniation pit. Acta Chir Orthop Traumatol Cech. 1993;60:351-3.
20. Nokes SR, Vogler JB, Spritzer CE, Martinez S, Herfkens RJ. Herniation pits of the femoral neck: appearance at MR imaging. Radiology. 1989;172:231-4.
21. Lee E, Choi J. Association between alpha angle and herniation pit on MRI revisited in 185 asymptomatic hip joints. Korean J Radiol. 2015;16:1316-9.