The geometry of the osteotomy requires a good deal of shortening to achieve significant correction of intermetatarsal angle. This was expected to reduce first ray loading and lead to a high incidence of metatarsalgia.
However, Klosok's RCT of Wilson vs chevron osteotomy found that metatarsalgia was actually commoner in the DCO group, associated with more recurrent hallux valgus. Pouliart found that 35% had metatarsalgia and a short hallux, but over 90% had good clinical results, and other series have reported similar results.
These results raise the hypothesis that shortening adds more to first ray function, by reducing the hallux valgus angle without tension, than it removes. More detailed clinical and biomechanical studies are needed to test this hypothesis.
Although the Wilson osteotomy is currently out of favour, further study is warranted to clarify whether it may have a legitimate place. The poor quality of most of the series of Wilson procedures hampers accurate judgement, but the RCT by Klosok cannot be ignored. On the other hand, further studies may find the Klosok trial to be an outlier and the Wilson procedure to have an unacceptably high rate of complications, especially metatarsalgia. It's probably best not to suggest the Wilson osteotomy in the exam at the moment!