Happens like 43 said. when the other foot has to take more weight the hip will start to wear from the extra stress.

Actually have that problem with my right knee. While both knees are worn , after having torn the acl, and mcl

in my left knee, not only did putting more of my weight on the right leg/knee/hip , but my right knee started acting up again.

Both knees are going to have to be replaced. Not looking forward to going under again(have been under 6/7 times in the last 5 years)

But having to rehab one and then doing it all over again sucks.