Clubfoot deformity in the Solomon Islands: Melanesian versus Polynesian ethnicity, a retrospective cohort study

Purpose Congenital talipes equinovarus (CTEV) has a high incidence in the South Pacific, with New Zealand Maori and Polynesian rates of up to seven per 1000 live births, at least five times higher than the Caucasian population. A genetic component is suggested to explain this, however, there is little information regarding the difference of incidence between Polynesian and Melanesian ethnicity in the South Pacific. Our aim was to investigate the effects of ethnicity on the incidence of CTEV in the Solomon Islands, specifically comparing Melanesian and Polynesian ethnicity. Methods Between 2011 and 2017, data was collected in the Solomon Islands from over 40 clinics upon introduction of the Ponseti programme for treatment of CTEV. Records were kept using the validated Global Clubfoot Initiative data form. Ethnicity was documented, including family history. Results In total, 138 children presented during this period, with 215 affected feet reviewed and treated. In all, 74% of children had solely Melanesian parents and 6% Polynesian. Using the general population ethnic breakdown of 95.3% Melanesian and 3.1% Polynesian, the odds of CTEV in children of Melanesian parents were 0.41 times lower compared with the odds in children of Polynesian parents. Conclusion The results indicate that in the Solomon Islands, CTEV in Melanesian children was less than half as likely to occur in Polynesian children. Our findings also support the theories of minimal Polynesian genetic material persisting in the Solomon Islands and a different genetic risk of CTEV between Polynesians and Melanesians. Level of Evidence III