RT Journal Article SR Electronic T1 The old knee in the young athlete: knowns and unknowns in the return to play conversation JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 505 OP 506 DO 10.1136/bjsports-2015-095481 VO 50 IS 9 A1 Clare L Ardern A1 Karim M Khan YR 2016 UL http://bjsm.bmj.com/content/50/9/505.abstract AB