Prevalence of hallux valgus: an observational post-mortem based study at the University Teaching Hospital, Lusaka

Background. Hallux valgus is the lateral deviation of the big toe towards the other toes of the same foot. It is one of the commonest orthopaedic conditions of the forefoot. There are many risk factors including heredity, sex, age and footwear. The condition can progress to a painful stage where surgery, which may be expensive, is indicated. Numerous studies have been conducted to investigate its aetiology and demographics. However, the prevalence of hallux valgus in Zambia is not known. The gold standard for studying hallux valgus is radiology. However, because of lack of such a modality, the clinical Manchester Scale was used instead as it gives the necessary information on angulation deformity which is the main objective of the study.
Objectives. To determine the prevalence of hallux valgus, and its distribution with gender, age and foot length among dead bodies brought in for autopsy at the UTH mortuary
Method and equipment. Three hundred and forty five dead bodies qualified for the study. Each foot was set in a standard position, on a glass jig, at 90 degrees dorsiflexion. Then, hallux vulgas was measured using the Manchester scale. Foot-length of the left was measured, on a line joining the most distal point of the ball of the longest toe to the most proximal part of the calcaneal pad, using a metric ruler.
Results. The prevalence of HV was found to be at 2.6 per cent (9 cases) by clinical definition and 34.6 (118 cases) per cent radiographically, by extrapolation. There was 1.45 percent (5 cases) prevalence among females and 1.15 per cent (4 cases) male even though there was no statistical association between HV and gender (p-value>0.05). The prevalence of HV increased with age, and was highest (41 cases, 21.7 per cent) in the 30 to 49 year age group (p- value<0.05). The prevalence of HV increased with foot length with the 20 cm to 30 cm foot length category having a peak frequency of 75 cases (p-value<0.05).
Conclusion Prevalence of HV is 2.6 per cent. The frequency of HV among females is 1.45 per cent and 1.15 per cent among males. The age group with most moderate and severe HV (1.7 per cent) is 30 to 49 years. Furthermore, within each age group there was an increasing trend with ageing. HV is greatly prevalent among feet in the 25 to 30 cm range (1.4 per cent). Furthermore, an increasing trend of HV was evident with increasing foot length in the other groups.
Key words: Hallux Valgus; Manchester scale; Post-mortem; Lusaka