A hip replacement — also called hip arthroplasty — is surgery to repair a diseased or injured hip joint by replacing it with an artificial joint or implant. People usually receive these surgeries because osteoarthritis causes hip pain and inflammation. Hip fracture and natural wear-and-tear are also common reasons for hip replacement surgery.
Hip replacements help millions of people regain mobility and find relief from joint pain, but hip replacement surgery is accompanied by some risk and requires months of recovery.
Prospective patients should know that implants don’t last forever, and some hip implants have a better safety record than others. They should take steps to be sure a hip replacement is right for them and that the device they’re receiving has a history of success.
An artificial hip has three basic components: a stem that is inserted into the femur, a ball that attaches to the top of the femur and a cup that attaches to a socket in the pelvis. The ball, also called a femoral head component, replaces the head of the femur. The cup, also called the acetabular component, is implanted into the pelvis.
Hip replacements are one of the most common joint replacement operations in the United States, with more than 300,000 performed in the country each year, according to the American Academy of Orthopaedic Surgeons. An estimated 2.5 million Americans were living with artificial hips in 2010, according to a study published in 2015 in The Journal of Bone and Joint Surgery.
Although hip replacement surgery is common, it is a major surgery that has a variety of risks. Complications during surgery or later in life can cause debilitating side effects. That’s why doctors and patients should consider the benefits and risks of the operation.
Candidates for Hip Replacement
The most likely candidates for hip replacement include people who experience pain that disrupts regular activities. In addition to people with osteoarthritis or hip injuries, people with rheumatoid arthritis, osteonecrosis or bone tumors may need hip replacements to relieve pain. People also receive hip replacements to increase mobility and improve overall quality of life.
Most doctors will ask patients to consider alternative methods for relieving pain or increasing mobility before recommending an artificial hip implant.
One such option called subchondroplasty attempts to promote natural bone growth to repair damaged hips. Doctors inject a bone substitute into the hip joint. The material fills gaps, voids and lesions in the bone. Over time, the body begins replacing the material with natural bone, which can sometimes lead to permanent repairs.
- Exercises that increase muscle around the hip
- Canes, walkers and other walking aids
- Over-the-counter medication for pain without inflammation
- Nonsteroidal anti-inflammatory drugs for pain with inflammation
- Osteotomy of the femur, a procedure that involves cutting and realigning the bone
But when alternative treatments do not provide relief, increase mobility or improve quality of life, doctors may consider a hip replacement procedure. They will analyze the patient’s medical history, take X-rays and perform physical exams to test hip mobility and strength. They may also conduct MRIs or CT scans.
Doctors will also consider the risk for each individual patient. Age, weight and medical conditions such as diabetes can affect a patient’s risk for complications following hip replacement, according to Dr. H. John Cooper, a board certified orthopedic surgeon.
The risk of getting a specific complication “can be somewhere between 0 and 3 percent for somebody who’s healthy and in good shape,” Cooper told Drugwatch. “There’s risk factors that are greater than 20 percent in patients with the wrong sort of combination of risk factors.”
People ages 50 to 80 have historically been the most common candidates for hip replacements. However, young teenagers with juvenile arthritis and people over the age of 80 have successfully undergone hip replacements.
Many people experience pain relief and improvements in daily living after receiving a hip replacement, but the devices are not miracle cures. Hip replacement surgery has a number of risks, and the implants wear out over time. To avoid complications, people who receive implants should not jog, run or participate in high-impact sports. They may be able to swim, bike or perform other low-impact activities.
Types of Hip Replacement Surgery
Surgeons perform hip replacements by using a posterior approach or an anterior approach. With a posterior hip replacement, the incision is made at the side or back of the hip. During anterior hip replacement, the surgeon makes the incision at the front of the hip.
The posterior approach is more common because it allows better visibility of the hip joint, and it is less invasive. No muscles have to be cut, which allows for quicker recovery.
Patients who are younger than 50, have a normal body mass index or who are in overall good health may be candidates for minimally-invasive surgery. During this surgery, the incision is smaller and recovery time after the surgery is shorter.
Special bone cement is commonly used to hold hip implants in place, but some surgeons use a cementless fixation technique. Devices that do not require cement have a textured surface that allows the bone to grow onto the implant and secure it. A hybrid total hip replacement involves implanting the cup without cement and setting the ball in place with cement.
Total Hip Replacement
Total hip replacement is the most common hip surgery. It uses artificial components to replace the entire hip structure. During the procedure, surgeons insert a stem into the patient’s femur, or thighbone, for stability. They replace the head of the femur with a ball and replace the natural socket in the hip joint with an artificial cup.
Partial Hip Replacement
Partial hip replacement removes and replaces the patient’s femoral head, which is the ball at the top of the femur, or thighbone. It does not replace the socket. A ceramic or metal ball is attached to the top of a stem that’s inserted into the hollow center of the femur. Surgeons typically perform this surgery to repair certain types of hip fractures.
Hip resurfacing helps relieve pain from cartilage loss. A surgeon trims damage from the natural bone ball at the top of the thighbone. He or she then resurfaces it with a smooth metal covering. The surgeon also lines the natural bone socket of the hip with a metal lining or shell.
Types of Implants
Device manufacturers design hip implants to mimic the natural movement of the body. The primary differences between implants are their size and the material of the components.
Hip implant components are made of polyethylene (plastic), metal, ceramic or a combination of the materials.
One of the most common types of hip implant, metal-on-polyethylene has been used since the 1960s. The ball is made of metal and the socket has a plastic lining or is made entirely of polyethylene. Plastic has a smooth surface that causes little friction while the ball moves within the socket. However, MoP implants can produce plastic debris, which can eventually cause the implant to fail. Wear debris from the breakdown of materials could lead to a condition called osteolysis, which occurs when inflammation destroys the bone and the implant in the bone loosens.
Metal-on-metal hip devices are no longer available in the United States, though thousands of people may have been implanted with them. Around the turn of the century, many new hip implants were made from metal-on-metal components, meaning the ball, stem and socket were all made out of metal. Manufacturers believed the metals were more durable than other materials. However, MoM hip implants can shed metal particles that may cause a number of serious health issues, including a type of metal poisoning called metallosis. Several models of metal-on-metal hips were recalled or taken off the market.
Ceramic-on-polyethylene devices couple a ceramic ball with a socket made from plastic. They may also substitute the plastic socket for a polyethylene lining in the natural socket. With plastic parts, there is still a risk of wear that causes debris that leads to osteolysis.
Ceramic-on-ceramic devices combine a ceramic head with a ceramic lining in the hip socket. A 20-year follow up study found that overall survivorship of CoC implants was 88 percent. It increased to 91 percent when researchers looked only at failures related to materials, according to Dr. Laurent Sedel, who presented the study at the SICOT XXV Triennial World Congress 2011. The most common failures were loosening of the lining and component fractures.
The U.S. Food and Drug Administration approved the first ceramic-on-metal hip device in 2011, making the design relatively new. The ball is made of ceramic and the socket has a metal lining.
Preparing for Surgery and Recovery
There are several ways to prepare for hip replacement surgery. In addition to learning about the surgery, patients should ask someone to help them during the first few weeks after they leave the hospital. If no one is available, a social worker or other form of assistance may be necessary.
Patients should organize their home so they have a comfortable place to spend their time.
- Attaching safety bars to a shower
- Putting a chair in the shower
- Raising the toilet
- Getting a device to help reach far-away objects
- Creating clear walkways throughout the house
Overweight patients should consider losing weight to decrease stress on the hip after surgery. Patients should take care of any dental work prior to undergoing hip replacement. Bacteria can enter the blood during dental procedures and cause infection in the hip after surgery.
Recovery After Surgery
Hip replacement surgeries usually last a few hours. Most people stay in the hospital for a couple of days after having a hip replacement.
Some health providers put a pillow or other device between the legs of patients to protect the hip during the first day after surgery. They also provide pain relievers, such as opioids and nonsteroidal anti-inflammatory drugs, to relieve immediate pain after surgery.
Doctors may ask their patients to use a spirometer, a device that helps them take deep breaths, to prevent pneumonia. Basic physical therapy, such as walking with a walker, usually begins within one day of surgery. Patients also learn strengthening exercises before being discharged from the hospital.
Recovery After Being Discharged
After leaving the hospital, patients can begin performing light activity in the home to increase mobility. Most patients receive a walking program that gradually increases daily activity and a physical therapy routine composed of simple exercises.
People who have hip surgery may have a weak appetite, but they should eat a balanced diet to improve tissue recovery. They should also take care of the incision point until stitches are removed.
Recuperating at Home
Recovery from hip surgery usually takes between three and six months. There are several steps patients can take to avoid common complications during this time. It is important to avoid falls and other injuries to the hip, so patients should use canes, crutches or walkers when necessary. They should also avoid stairs and other steep inclines during the first months after surgery.
To avoid infection, patients should talk to their doctor about taking antibiotics before dental operations. They should also take medications as prescribed to avoid blood clots. Special attention should be paid to sitting, sleeping and bending to avoid dislocating the hip.
Risks and Complications of Hip Surgery
Most people who have hip replacement surgery do not experience major complications. Dislocation and loosening are the most common complications of hip replacement, according to the National Institute of Arthritis and Musculoskeletal and Skin Disease.
- Loosening of implant
- Blood clots
- Bone growth beyond normal edges of the bone
Less than 2 percent of patients experience serious complications, such as joint infection, according to the American Academy of Orthopaedic Surgeons, and a 2014 review of research on hip replacements concluded that improved surgical safety and better post-operative care have resulted in a reduced mortality risk after total hip replacement surgery. Mortality during the 90-day period after surgery dropped from 0.56 percent in 2003 to 0.29 percent in 2011, according to the review published in Bone and Joint Research.
Some complications occur at much higher rates with specific implant designs, said Cooper, who is an assistant professor of orthopedic surgery at Columbia University Medical Center. He categorizes device-specific concerns into two major groups.
The first involves certain implants with metal-on-metal bearings that are associated with a higher risk for failure and metal release from the bearing’s surface. The other major class of concern involves metal-on-polyethylene bearings that release metal debris where the pieces of the stem or head come together.
“The reactions are similar: inflammation around the joints, fluid collections, and in more advanced cases, tissues damage, bone loss or some of the more rare but serious complications like blood vessel constriction or compressions,” Cooper said.
A couple of the devices have been recalled and are no longer commonly used in the United States or across the world. But there are still plenty of patients in the United States who have these devices inside of them, Cooper said. Some patients in the United States are walking around with implants that were not available in the United States but were available in Europe or in other countries, and they are having the same kinds of problems.
Most hip implants last for 10 years to 15 years, but the devices wear out more quickly if the patient has an active lifestyle. Some implants wear out faster than others, requiring revision surgery to remove, repair or replace the device. An estimated 10.4 percent of hip replacements require revision surgery, according to a 2016 study published in Arthroplasty Today.
Hip Implant Recalls
A hip replacement recall usually happens when the implant causes complications in large number of people implanted with the device. Several leading device makers have issued large recalls related to hip complications.
Johnson & Johnson subsidiary DePuy Orthopaedics issued a global recall for the company’s ASR and ASR XL Acetabular Cups in 2010. The reason given was the company’s “ongoing post-market surveillance,” meaning the company was reviewing reported problems. DePuy never recalled its metal-on-metal versions of its Pinnacle hip but quietly pulled them off the market. People have filed more than 20,000 lawsuits over DePuy’s ASR and Pinnacle metal-on-metal hips.
Stryker recalled 9,003 ABG II Modular hip stems in April 2012 after reports of fretting and corrosion. These devices were not metal-on-metal ball and socket components. The problem came from the connections in the stem that held the implant to the femur. The Stryker devices came with different sized and angled necks that allowed surgeons to customize fit for patients. The junction where these connected shed particles into patients’ tissue.
United Kingdom-based Smith & Nephew recalled all 6,266 lots of its Modular Redapt Hip Systems in 2016 due to “a higher than anticipated complaint and adverse event trend.” Just a year earlier, the company had recalled almost 6,000 Birmingham Hip Resurfacing, or BHR, components due to “revision rates which were higher than established benchmarks.”
Zimmer recalled 19,000 Durom cup components in 2008 because of false and misleading labeling. And Wright Medical recalled shells for its Conserve and Dynasty hip replacement lines in 2016 due to metal debris causing the need for revision surgeries in patients with the devices.
What to Know About Metal-on-Metal Implants
The FDA classifies metal-on-metal hip systems as Class III, higher risk medical devices, but many of them were cleared for sale in the United States through the agency’s 510(k) premarket notification process. Under the process, companies need only to show that their products are “substantially equivalent” to other devices already approved by the FDA before they can start selling their products.
“Metal-on-metal implants were commonly used up to a third of the time in hip replacement in the early and mid-2000s,” Cooper said.
The devices had higher than expected failure rates. Problems led companies to recall some models. Others were simply pulled off the market.
Today, there are no FDA-approved metal-on-metal hip implants available in the United States. There are only two FDA-approved metal-on-metal resurfacing systems available. And any company that wants to sell metal-on-metal hips can no longer rely on the 510(k) process. Companies have to provide scientific evidence that their devices are safe and effective.
“The patients with these more problematic or riskier implants need regular follow-up with an orthopedic surgeon familiar with hip or knee replacements.”
Studies and data from national registries showed metal wear debris from metal-on-metal hip implants can cause inflammation around the joints and local tissue damage with what doctors call adverse local tissue reactions, or ALTR.
“Often in these patients when these kinds of reactions develop, if caught early, the bearing surface can be changed so permanent damage is not typically done,” Cooper said.
But if the problem goes unaddressed for a period of time, then patients can suffer irreversible, permanent tissue damage or bone loss. In extreme cases, patients may experience nerve compression or compression of blood vessels. In very extreme cases, the metal being released from these joint replacements can get to high systemic levels in the blood and can potentially cause concern about systemic side effects that affect the patients’ heart, vision or hearing.
“The patients with these more problematic or riskier implants need regular follow-up with an orthopedic surgeon familiar with hip or knee replacements,” Cooper said. “If they haven’t been within the past year, I would recommend making an appointment with their surgeon who put the device in.”
Many people with these problematic artificial hips have opted for revision surgery to receive a new hip implant. Some patients filed lawsuits against hip implant manufacturers, claiming the companies knew their hip systems were defective.
Please seek the advice of a medical professional before making health care decisions.