While NSAID therapy has been effective in reducing the incidence of HO, it is associated with potentially serious side affects. Fransen et al found 202 GI side effects in a metaanalysis of 4328 patients taking NSAIDs for HO prophylaxis.1 Of these, 138 were minor (e.g. nausea, dyspepsia, diarrhea) and 64 were major (e.g. hematemesis or melena). Overall, there was a 31% increase in the risk of GI side effects among patients taking NSAIDs. Furthermore, NSAID therapy could impair bone and/or soft tissue healing following this. These side affects could negate the benefit of NSAID therapy, especially if HO is asymptomatic in the majority of patients.