1. 2009;12;E335-E339Chronic Regional Pain Syndrome after Subtalar Arthrodesis is Not Prevented by Early Hyperbaric Oxygen
   Case Report
   Simon TB Williams, MBBCh, Anthony Davies, FRCA, and Phil Bryson, MBBS.

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 5½ 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.