( ( While ( ( the procedure ) ( ( can not ) ( alter ( ( the ( natural history ) ) ( of ON ) ) ) ) ) ) ( , ( it ( probably ( ( ( allows ( ( the patient ) ( a ( ( more ( ( comfortable and ) painfree ) ) life ) ) ) ) ( until ( , ( eventually ( , ( ( ( he or ) she ) ( will ( have ( to ( ( undergo ( ( THR , ) ( ( ( ( between five ) and ) ten ) years ) ) ) ( after ( ( the collapse ) ( of ( the ( femoral head ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (SBAR (IN While) (S (NP (DT the) (NN procedure)) (VP (MD can) (RB not) (VP (VB alter) (NP (NP (DT the) (JJ natural) (NN history)) (PP (IN of) (NP (NNP ON)))))))) (, ,) (NP (PRP it)) (ADVP (RB probably)) (VP (VBZ allows) (S (NP (DT the) (NN patient)) (NP (DT a) (ADJP (RBR more) (JJ comfortable) (CC and) (JJ painfree)) (NN life))) (SBAR (IN until) (S (, ,) (ADVP (RB eventually)) (, ,) (NP (PRP he) (CC or) (PRP she)) (VP (MD will) (VP (VB have) (S (VP (TO to) (VP (VB undergo) (NP (NP (NNP THR)) (, ,) (NP (QP (IN between) (CD five) (CC and) (CD ten)) (NNS years))) (PP (IN after) (NP (NP (DT the) (NN collapse)) (PP (IN of) (NP (DT the) (JJ femoral) (NN head))))))))))))) (. .)))
While the procedure cannot alter the natural history of ON, it probably allows the patient a more comfortable and painfree life until, eventually, he or she will have to undergo THR, between five and ten years after the collapse of the femoral head.
(ROOT (S (NP (CD Five) (JJ mass) (NNS distinctions)) (VP (VBP have) (ADVP (RB radically)) (VP (VBN altered) (NP (NP (DT the) (NN history)) (PP (IN of) (NP (NN life)))))) (. .)))