Fighters who's careers was ruined by injurys

[Broomhall]

More recently Tony Jefferies career ruined by hand injuries, also Antony Ogogos career is in doubt. Achilles injuries can be very difficult to recover from.
Darren Barker had troubles throughout his career and eventually had to stop through hip problems.

[bennie]

Philly's Leotis Martin took part in one of the greatest heavyweight battles ever seen in this country when he stopped Thad Spencer in nine rounds at the Albert Hall in 1968. A year later Martin flattened Sonny Liston but that was it for the 30-year-old who never fought again (retina); another Philly puncher, Cyclone Hart, was 21-0 (20) when he fell out of the ring in a fight with Denny Moyer (who fell with him) and landed on his head at the Spectrum in 1971. Hart was never the same.

[Broomhall]

Three very sad cases also spring to mind would be Gypsy Joe Harris who fought much of his career with one eye until it was discovered and he was banned, Sugar Ray Seales was another man whose career was destroyed by poor eyesight. Also Irish Billy Collins who never recovered from the injuries in the Resto fight where Restos gloves were doctored. Joey Gamache was brain damaged in his fight with Gatti where there was much controversy over Gattis weight.
Richard Grant also had his career ruined by James Butlers infamous sucker punch.

[Syntax Error]

Willie Pep?

OK, his career wasn't 'ruined', but he was certainly disadvantaged by the injuries he received following a plane crash.

[bripez]

Also Irish Billy Collins who never recovered from the injuries in the Resto fight where Restos gloves were doctored

This is the number 1 for me.

Absolutely horrific what happened here, and the subsequent death of Collins adds to that.