Again anecdotally, I have a keen running doctor friend in the UK who had 2 hip replacements by the time he was 40. Now that he's in his mid 50s, he's looking at

Again anecdotally, I have a keen running doctor friend in the UK who had 2 hip replacements by the time he was 40. Now that he's in his mid 50s, he's looking at replacements for his replacements.