Chronic regional pain syndrome after subtalar arthrodesis is not prevented by early hyperbaric oxygen.

Subtalar arthrodesis was performed on a 48-year-old, non-insulin-dependent diabetic with a history of chronic ankle instability and lateral ankle pain. In the early post-operative period he presented as an emergency with an infection at the operative site. This was treated with 2 returns to the operating theatre for washout and debridement. His wounds were left open and at 3 weeks after emergency admission he was referred for adjunctive hyperbaric oxygen (HBO) therapy to aid healing by secondary intention. He received a total of 19 hyperbaric sessions, at a pressure of 2.2 ATA, one treatment per day for 5 days a week. Shortly after commencing HBO therapy his ankle became increasingly painful, despite the introduction of analgesia. By 7 weeks after emergency admission his wounds had virtually healed but hyperesthesia persisted over the dorsum of the foot. A computerized tomography scan at 5 1/2 months post-operatively showed satisfactory joint fusion and revealed no evidence of infection. Symptoms and signs at this time were compatible with a diagnosis of chronic regional pain syndrome (CRPS). There is published evidence to suggest that HBO therapy may be a useful modality in the treatment of established CRPS. Here, we seek to publicize a case in which early treatment with HBO for another indication did not prevent the simultaneous development of CRPS Type 1.