Geographical Differences in the Forefoot Morphology – A Comparative Radiological Study of Feet in Malawi and UK

Abstract

Background: Many skeletal morphological differences between populations have been reported with possible but unproven clinical importance. This study was aimed at identifying the normal radiographic findings and measurements seen in patients from Southern Africa and compares them to a European population’s values.

Methods: AP foot radiographs of 40 adults from Blantyre, Malawi were compared with those of 40 adults from London, UK. For each patient, measurements were taken of: 1^st and 2^nd metatarsal lengths, the 1st/2nd intermetatarsal angle, the 1^st metatarso- phalangeal angle (the ‘bunion’ angle), and the 2^nd metatarsal mortice joint medial and lateral depths.

Results: Our results show an increased 1^st/2^nd metatarsal angle in Malawian feet, but a reduced ‘bunion’ angle. We also found the second metatarsal length to be longer relative to the first in the Malawian foot, and the 2^nd metatarsal base to be significantly more covered by its mortice than in UK feet.

Conclusion: This racial anatomical variation may convey more stability and less risk of a Lisfranc dislocation. It is also important to be aware of the normal range of these values when considering the need for forefoot arthroplasty procedures.