My father was just told he has advanced-stage arthritis of his left hip and needs a joint replacement. How serious is this?

Osteoarthritis (OA) is classified or staged according to changes in the size of the hip joint space and condition of the bone. As the cartilage wears down, the joint space gets narrower. Bone spurs called osteophytes start to form around the edges of the bone.

These and other changes are seen on X-rays. Advanced OA is defined as narrowing of the joint space along with spots of radiolucency from bone erosion. Radiolucency means the image is dark because the X-rays have passed through where the bone has worn away.

Of the four stages of OA, advanced-stage is the third stage before the final end-stage arthritis. In end-stage disease, the joint space is absent and bone spur formation is severe.

Patients with advanced or end-stage disease are most likely to be considered for joint replacement. Younger patients with advanced stage disease may be able to have a procedure called joint resurfacing. Then later, if the joint wears out completely, a joint replacement is possible. Older patients (usually 65 years or older) are more likely to receive a total joint replacement.