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lifetime risk for females was seen in Norway and the greatest lifetime risk for females was in Finland, closely followed by Australia (Table II). For males, the lowest lifetime risk of TKR was in Norway and the highest lifetime risk was in Australia. Similar to the 2003 data, females consistently demonstrated a higher lifetime risk of TKR across all countries in 2013. The difference in lifetime risk between sexes was greatest in Finland, where the risk for females in 2013 was almost double the risk for males (22.79% vs 11.68%; P < 0.05). Changes in lifetime risk of TKR over time Each country demonstrated a significant increase in the lifetime risk of TKR from 2003 to 2013 for both females and males. For females, the greatest absolute increases in lifetime risk over time were evident for Australia and Denmark (Fig. 1), while Finland and Norway had the smallest absolute change. All five countries also Table I Population characteristics and TKR demographics Country Population data TKR data from registries Population size % Female Life expectancy* Number of primary TKRy % Femalez % Aged < 0.05 for all 2003e2013 comparisons. For these estimates, simultaneous bilateral TKR was counted as one TKR procedure to avoid potential over-estimation of lifetime risk. Where staged bilateral TKR procedures were performed within the same year, only the first procedure was included in the dataset.

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