Seasonal variation in adult hip disease secondary to osteoarthritis and developmental dysplasia of the hip

AIM To determine if there was a seasonal variation in adults undergoing total hip arthroplasty for end stage hip disease due to osteoarthritis (OA) or sequelae of developmental dysplasia of the hip (DDH). METHODS The total hip registry from the author's institution for the years 1969 to 2013 was reviewed. The month of birth, age, gender, and ethnicity was recorded. Differences between number of births observed and expected in the winter months (October through February) and non-winter mo (March through September) were analyzed with the χ2 test. Detailed temporal variation was mathematically assessed using cosinor analysis. RESULTS There were 7792 OA patients and 60 DDH patients who underwent total hip arthroplasty. There were more births than expected in the winter months for both the DDH (P < 0.0001) and OA (P = 0.0052) groups. Cosinor analyses demonstrated a peak date of birth on 1st October. CONCLUSION These data demonstrate an increased prevalence of DDH and OA in those patients born in winter.