Conditions that can damage the hip joint, sometimes necessitating hip replacement surgery, include:

• Osteoarthritis. Commonly known as wear-and-tear arthritis, osteoarthritis damages the slick cartilage that covers the ends of bones and helps joints move smoothly.
• Rheumatoid arthritis. Caused by an overactive immune system, rheumatoid arthritis produces a type of inflammation that can erode bone and cartilage and deform joints.
• Osteonecrosis. If there is inadequate blood supply to the ball portion of the hip joint, the bone may collapse and deform.

You might consider hip replacement if you're experiencing hip pain that:

• Persists, despite pain medication
• Worsens with walking, even with a cane or walker
• Interferes with your sleep
• Affects your ability to go up or down stairs
• Makes it difficult to rise from a seated position

Risks associated with hip replacement surgery may include:

• Blood clots. Clots can form in your leg veins after surgery. This can be dangerous because a piece of a clot can break off and travel to your lung, heart or rarely your brain. Your doctor may prescribe blood-thinning medications to reduce this risk.
• Infection. Infections can occur at the site of your incision and in the deeper tissue near your new hip. Most infections are treated with antibiotics, but a major infection near your prosthesis may require surgery to remove and replace the prosthesis.
• Fracture. During surgery, healthy portions of your hip joint may fracture. Sometimes the fractures are so small that they heal on their own, but larger fractures may need to be corrected with wires, pins and possibly bone grafts.
• Dislocation. Certain positions can cause the ball of your new joint to become dislodged. To avoid this, it is often recommended that after surgery you don't bend more than 90 degrees at the hip and don't let your leg cross the midline of your body. If the hip dislocates, your doctor may fit you with a brace to keep the hip in the correct position. If your hip keeps dislocating, surgery is often required to stabilize it.
• Change in leg length. Your surgeon takes steps to avoid the problem, but occasionally a new hip makes one leg longer or shorter than the other. Sometimes this is caused by weakness in the muscles surrounding the hip. In this case, progressively strengthening and stretching those muscles may help.
• Loosening. Although this complication is rare with newer implants, your new joint may not become solidly fixed to your bone or may loosen over time, causing pain in your hip. Surgery might be needed to fix the problem.

Need for second hip replacement

Your prosthetic hip joint may wear out eventually, so if you have hip replacement surgery when you're relatively young and active, you eventually may need a second hip replacement. However, new materials are making implants last longer, so a second replacement may not be needed for many years.

Metal-on-metal complications

Most artificial hip joints have a polished metal or ceramic ball that fits into a cup liner that's made of very hard plastic. Some types of prostheses use a metal cup liner, which may last longer but can cause other problems. Metal-on-metal prostheses are more likely to release metal ions into your bloodstream, which can cause inflammation and bone erosion. Because of these concerns, metal-on-metal prostheses are now rarely used.

Before surgery you'll meet with your orthopedic surgeon for an examination. The surgeon will:

• Ask about your medical history and current medications
• Do a brief general physical examination to make sure you're healthy enough to undergo surgery
• Examine your hip, paying attention to the range of motion in your joint and the strength of the surrounding muscles
• Order blood tests, an X-ray and possibly an MRI

This preoperative evaluation is a good opportunity for you to ask questions about the procedure. Be sure to find out which medications you should avoid or continue to take in the week before surgery.

When you check in for your surgery, you'll be asked to remove your clothes and put on a hospital gown. You'll be given either a general anesthetic or a spinal block, which numbs the lower half of your body.

During the procedure

To perform a hip replacement, your surgeon:

• Makes an incision over the front or side of your hip, through the layers of tissue
• Removes diseased and damaged bone and cartilage, leaving healthy bone intact
• Implants the prosthetic socket into your pelvic bone, to replace the damaged socket
• Replaces the round top of your femur with the prosthetic ball, which is attached to a stem that fits into your thighbone

Techniques for hip replacement are evolving. As surgeons continue to develop less invasive surgical techniques, the hope is that these techniques might reduce recovery time and pain compared with standard hip replacements. However, studies comparing the outcomes of standard hip replacement with those of minimally invasive hip replacement have had mixed results.

After the procedure

After surgery, you'll be moved to a recovery area for a few hours while your anesthesia wears off. Nurses or other anesthesia aides will watch your blood pressure, pulse, alertness, pain or comfort level, and your need for medications.

Blood clot prevention

After your surgery, you'll be at increased risk of blood clots in your legs. Possible measures to prevent this complication include:

• Early mobilization. You'll be encouraged to sit up and even try walking with crutches or a walker soon after surgery. This will likely happen the same day as your surgery or on the following day.
• Pressure application. Both during and after surgery, you may wear elastic compression stockings or inflatable air sleeves similar to a blood pressure cuff on your lower legs. The pressure exerted by the inflated sleeves helps keep blood from pooling in the leg veins, reducing the chance that clots will form.
• Blood-thinning medication. Your surgeon may prescribe an injected or oral blood thinner after surgery. Depending on how soon you walk, how active you are and your overall risk of blood clots, you may need blood thinners for several more weeks after surgery.

Physical therapy

A physical therapist may help you with some exercises that you can do in the hospital and at home to speed recovery.

Activity and exercise must be a regular part of your day to regain the use of your joint and muscles. Your physical therapist will recommend strengthening and mobility exercises and will help you learn how to use a walking aid, such as a walker, a cane or crutches. As therapy progresses, you'll gradually increase the weight you put on your leg until you're able to walk without assistance.

Home recovery and follow-up care

Before you leave the hospital, you and your caregivers will get tips on caring for your new hip. For a smooth transition:

• Arrange to have a friend or relative prepare some meals for you
• Place everyday items at waist level, so you can avoid having to bend down or reach up
• Consider making some modifications to your home, such as getting a raised toilet seat

About six to eight weeks after surgery, you'll have a follow-up appointment with your surgeon to make sure your hip is healing properly. If recovery is progressing well, most people resume their normal activities by this time — even if in a limited fashion. Further recovery with improving strength will often occur for six to 12 months.

Expect your new hip joint to reduce the pain you felt before your surgery and increase the range of motion in your joint. But don't expect to do everything you couldn't do before surgery. High-impact activities — such as running or playing basketball — may be too stressful on your artificial joint. But in time, you may be able to swim, play golf, hike or ride a bike comfortably.