hello pika l feel so sorry for your mom , l had my left hip replaced feb 2006 and it didnt work l am going back into hospital on sunday to have it done again, l have the same symtoms as your mom l was told it was nerve ends ,then l was told it was muscular,pt was so painful and l new after ten months that it wasnt right, somtimes you have to shout to be heard and thats what l had to do, finally l was sent for a bone scan and it showed that it was loose this is very rare it happens to about one in every hundred trust me to be one of the 1%,it takes some people longer to recover than others but a bone scan will put your mind at rest,l do hope everything turns out ok for your mom hatty