Relation between hospital orthopaedic specialisation and outcomes in patients aged 65 and older: retrospective analysis of US Medicare data

Objective To explore the relation between hospital orthopaedic specialisation and postoperative outcomes after total hip or knee replacement surgery.Design Retrospective analysis of US Medicare data, 2001-5.Setting 3818 US hospitals carrying out total joint replacement.Population 1 273 081 Medicare beneficiaries age 65 and older who underwent primary or revision hip or knee replacement.Main outcome measures Hospitals were stratified into fifths on the basis of their degree of orthopaedic specialisation (lowest fifth, least specialised; highest fifth, most specialised). The primary outcome was defined as a composite representing the occurrence of one or more of pulmonary embolism, deep vein thrombosis, haemorrhage, infection, myocardial infarction, or death within 90 days of the index surgery.Results As hospital orthopaedic specialisation increased from the lowest fifth to highest fifth, the proportion of people admitted who were women or black, or who had diabetes or heart failure progressively decreased (P