I listened to the 'Quickly Kevin Will he Score?' podcast today, in December they did a long interview with Sir Brian Little, talking about his time as a player and manager (well worth a listen, btw), and he was talking about his retirement, effectively being due to an ACL, and how these days it's ultimately bad but recoverable, but in his time, it was a career-ender.
26 when he had to retire. What a player he was, I honestly think he's still my favourite Villa player ever (largely because i was a young kid when he was in his prime and used to hero worship him).