This is a multicentresite retrospective review from four clinics in the USA on patients who received radical debridement and free flap reconstruction for osteoradionecrosis (ORN) between 1 Jan 1995 and 30 June 2011. Patients were stratified divided based on having prior undergone prior hyperbaric oxygen (HBO) treatment or not. Eighty-nine patients received a free flap reconstruction, of these 39 had a history of HBO and 50 did not. A total of 56% with prior HBO developed complications compared with 50% without prior HBO therapy, there was no statistical difference. However there was a marginal significant increase in infections rate in patients with HBO therapy. Interestingly this group also had a lower incidence of diabetics. This is a first study that examines the association of prior HBO and postoperative complications. This data suggests that patients that have continued ORN with failed conservative therapy and HBO are at risk for postoperative infections. This may be a selection bias because these patients failed conservative and initial treatment of ORN. Also repeated debridement could account for repeated injury. The authors accept the limitations of this retrospective study and accept that causality cannot be determined by this. It is however a well written paper that brings together patients, with a fairly uncommon and difficult condition, from four large centres and is worth reading.