Avascular necrosis of the first metatarsal head following Austin osteotomy: a follow-up study.

A prospective study is described of 12 consecutive patients with hallux abducto valgus deformity in whom an Austin osteotomy without lateral release was performed. All patients had similar postoperative care and magnetic resonance images (MRI) studies of their first metatarsals. The MRI was performed in T1- and T2-weighted images with algorithms programmed to image changes in the bone consistent with avascular necrosis of the first metatarsal head. One of the 12 patients following Austin osteotomy without lateral release had changes on MRI consistent with avascular necrosis of the first metatarsal head. These results were then compared with the prior study of 20 patients that had the Austin osteotomy with lateral release using the Fisher's exact test for small populations, and a value of 0.023 was found (0.05 > 95% confidence level). The Austin osteotomy with lateral release significantly increases the risk of developing avascular necrosis of the first metatarsal head and should only be performed in instances where the soft tissue contracture is largely contributing to the hallux abducto valgus deformity.