Fusion of the first MTP joint in a corrected position will correct deformity. The intermetatarsal angle usually reduces in the months after surgery as the pressure of the phalanx against the metatarsal head is reduced; a first metatarsal osteotomy is not usually necessary. Humbert (1979) found a mean correction of 5deg in IMA, often apparent in radiographs taken immediately post-operatively. Dayton (2002) found an improvement of 6.4deg, and Cronin (2006) found that the IMA reduced from 16 to 8 deg over 13 months.
Humbert (1979) reported good or excellent results in 31 patients using a tongue-and-trough method without fixation or splintage. There were 7 non-unions (29%) although only 2 were symptomatic.
Coughlin (2005) described 21 fusions for primary hallux valgus, with a mean of 8y follow-up. The mean age at surgery was 71, and the majority of patients had a hallux valgus angle of >40deg. Pain scores were markedly improved, with an average AOFAS hallux score of 84 and all patients able to wear commercially available shoes. There were 3 non-unions, one of which was symptomatic.
The same group (Grimes 2006) reported 33 fusions for a variety of failed previous halllux valgus procedures. Fixation was with a dorsal plate in most patients. The mean post-op AOFAS hallux score was 73/100 and 72% of patients had few or no symptoms. There were 4 non-unions (12%) although only one was symptomatic.
Fusion can even be used as salvage for failed hallux valgus surgery with infection. Myerson (1994) carried out a throrough debridement, insertion of a spacer and temporary fixation followed by arthrodesis with tricortical iliac crest graft, in five patients. However, 2 patients had pseudarthrosis. We have used a similar procedure in patients who presented with severe hallux valgus and infected skin breakdown over the medial eminence.