Associated correction of forefoot alignment with hindfoot fusion for pes planovalgus deformity.

BACKGROUND: The present study aimed to investigate changes in hallux alignment after corrective surgery for adult-acquired flatfoot deformity (AAFD). PATIENTS AND METHODS: The present study retrospectively investigated the changes of hallux alignment in 37 feet (33 patients) which were treated with double or triple arthrodesis of the hindfoot for AAFD between 2015 and 2021 and could be followed up to one year postoperatively. RESULTS: Hallux valgus (HV) angle significantly decreased by a mean 4.1° among the whole 37 subjects and by a mean 6.6° among the 24 subjects who had a preoperative HV angle of 15° or more. Those who had HV correction (HV angle correction ≥ 5°) demonstrated more near-normal postoperative alignment of the medial longitudinal arch and hindfoot than those without HV correction. CONCLUSIONS: Hindfoot fusion for AAFD could improve preoperative HV deformity to some degree. HV correction was associated with proper realignment of the midfoot and hindfoot. LEVEL OF EVIDENCE: Level IV; retrospective case series.