Seasonal Trends in the Incidence of Hip Osteoarthritis in Japanese Patients

Satomi Nagamine, Motoki Sonohata*, Masaru Kitajima, Syunsuke Kawano, Kenji Ogawa, Masaaki Mawatari , Takao Hotokebuchi
Department of Orthopedic Surgery, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, Japan

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© Nagamine et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Nabeshima 5-1-1, Saga 849-8501, Japan; Tel: +81-952-34-2343; Fax: +81-952-34-2059; E-mail:



There is an association between winter birth and developmental dysplasia of the hip, formerly termed congenital dislocation of the hip. The purpose of this study was to clarify the relationship between the month and season of birth and hip osteoarthritis in Japanese patients who had undergone total hip arthroplasty or transpositional osteotomy of the acetabulum.


One thousand eight hundred and 52 female patients that presented for the surgical treatment of hip osteoarthritis between 1999 and 2005 were included in this study. Female out-patients who were seen at the initial visit during same period were used as controls to correct the bias of the month of birth.


There was a significant deviation of the observed number of births from the expected values calculated on a monthly basis (p<0.001). A comparison by seasons (periods of 3 months) revealed more births than expected in winter (p<0.001). The risk of hip osteoarthritis was significantly associated with the month of birth. Namely, it was highest for births in January (p<0.001).


These data clearly revealed that the prevalence of hip osteoarthritis was significantly higher in those patients born in winter. The seasonal trend in hip osteoarthritis might be due to the winter prevalence of congenital dislocation of the hip in childhood.

Keywords: Seasonal trend, hip, osteoarthritis, acetabular dysplasia, Japanese.