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-dependentdiabetic with a history of chronic ankle instability and lateral ankle pain. In theearly post-operative period he presented as an emergency with an infection atthe operative site. This was treated with 2 returns to the operating theatre forwashout and debridement. His wounds were left open and at 3 weeks afteremergency 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 daysa week.Shortly after commencing HBO therapy his ankle became increasingly painful,despite the introduction of analgesia. By 7 weeks after emergency admissionhis wounds had virtually healed but hyperesthesia persisted over the dorsumof the foot. A computerized tomography scan at 5½ months post-operativelyshowed 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 inwhich early treatment with HBO for another indication did not prevent the simultaneous development of CRPS Type 1.Key words: Subtalar arthrodesis, hyperbaric oxygenation, chronic regionalpain syndrome