Sorry to hear this Danny.

I had my right hip replaced in March this year. I'm 71, in very good shape, normal weight. Left hip still ok. I don't sense any leg-length discrepancy, other than the first few months after surgery.

Just one idea, check out orthotic maker GoodFeet. I started wearing these a year ago and they have helped with my gait and posture.

I hope something clicks and works for your wife. Low back pain is just nasty and there should be a way to reduce or eliminate that.

All the best to you and your wife.

Joe