by Charles Sorbie, MB, ChB, FRCS(E), FRCS(C)
The incidence of club foot (approximately 0.8/1000 to 1.0/1000 live births) has remained much the same, at least in Scandinavia, from the earliest studies in 1913 until 1990. During the 1990s, however, it rose to 1.2/1000 in Denmark and 1.4/1000 Sweden, and for no clear reason. It is 6 times more common in east Asian countries.
Club foot comes in several forms and degrees of severity. The World Health Organization lists 12 variant diagnostic types within the International Statistical Classification of Diseases and Related Health Problems (ICD-9) club foot category. Two studies looking at incidence have come from Denmark (Acta Orthop. 2006; 77[6]:839-846) and Sweden (Acta Orthop. 2006; 77[6]:847-852). Both of these countries have well-organized, detailed national disease registries. The authors examined the incidence of club foot in 3 specific areas: entire countries, local population densities, and immigrant groups. Club foot has been known since ancient times and does not respect social status. Lord Byron is a prime example—born in London in 1788 to aristocratic parents and of high intelligence.
The Danish studies covered a period >16 years and included 936,525 births. The Swedish study compared the national, stable, low annual incidence existing through the early 20th century to the raised incidence (280 cases) in 1995 to 1996. Interesting facts were noted: both feet are affected in half the cases, three-fourths of the cases are boys, and there is no seasonal variation in occurrence. Both studies reported an increased incidence in areas of high population density, suggesting exogenous factors. There was no increase in children born to non-Scandinavian parents in Denmark, but immigration numbers had some influence in southern Sweden. As shown by other studies, intra-uterine pressure is not a causative factor (J Pediatr Orthop B. 2002; 25[11]:129-133).
The recent increased incidence of club foot is yet to be explained.
Blue Notes Editor:
Charles Sorbie, MB, ChB, FRCS(E), FRCS(C)
Dr. Charles Sorbie is Professor of Surgery at Queen’s University and a member of the Attending Staff at the General and Hotel Dieu Hospitals in Kingston, Ontario.A former chairman of the Department of Surgery at Queen’s University, Dr. Sorbie has been President of the Canadian Orthopaedic Research Society, the Canadian Orthopaedic Association, and the Societé Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT).