My Husband Had Hip Replacement Surgery In July. Was Recovering

My husband had hip replacement surgery in July. Was recovering okay. About a month ago, while at the store, while trying to use his cane, he tried to enter the bathroom and stumbled. Didn't fall, but had a sharp pain in his hip. Pain got worse until now it hurts to bear weight on it and he has to physically move the leg. But orthopedic Dr says hip is in place.
His primary Dr did an xray on his back and there are some issues there. Is this what the major problem could be? Is there anything we can do to help alleviate the pain? Do we need to see a specialist about the back issues? Any advice would be greatly appreciated. Thanks