By Kevin MacDonald, MD
Virginia Mason Hospital and Seattle Medical Center.
As an orthopedic surgeon, I spend a fair amount of time working with an experienced team performing various types of hip and knee replacement surgery on appropriate patients.
Joint replacement is a surgical procedure where parts of an arthritic or damaged joint are removed and replaced with a metal, plastic or ceramic device called a “prosthesis.” The prosthesis is designed to replicate the movement of a normal, healthy joint.
Types of joints
Before proceeding, some basic anatomy might be helpful. A joint is where the ends of two or more bones meet, an intersection if you will. The body includes different types of joints. For instance, the hip and shoulder are called “ball-and-socket” joints because the rounded end of one bone sits inside a cup-shaped area of another bone. And the knee is called a “hinge” joint, since it can bend and straighten like a hinged door.
National statistics should help give people an idea of why many orthopedic surgery practices around the country are busy. When you combine the number of baby boomers reaching “the golden years” with the pervasiveness of osteoarthritis – or degenerative joint disease – and the growing obesity epidemic, experts predict that by 2030 there will be almost 3.5 million total knee replacements and more than 570,000 hip replacements performed annually in the United States.
And although hip and knee replacements are the most commonly performed joint replacements, joint replacement surgery is also performed on the ankle, elbow, shoulder and wrist.
When to consider surgery
You might be considering joint replacement surgery if a hip or knee has been painful and is restricting movement. Although immediate benefits of surgery include less pain and enhanced mobility, you should first exhaust non-surgical options for management.
I remind all my patients that joint replacement surgery is elective and should come down to a quality-of-life decision. My advice almost always includes recommending that they try non-surgical treatments first – whether that be ice, heat, anti-inflammatory medication, swimming or physical therapy.
However, if nothing works, people should ask themselves if pain and disability are destroying their quality of life. If the answer is yes, I advise them that it’s the appropriate time to discuss surgical options.
Like every type of surgery, joint replacement is not without risks, which include:
- Damage to a blood vessel or nerve
- Loosening or dislocation of the new joint over time
- Medical complications, such as heart attacks or blood clots, due to the physical stress of undergoing surgery
Fortunately, these risks can be significantly reduced with good management before and after surgery, which most orthopedic surgery centers are very experienced at providing.
The benefits of joint replacement surgery shouldn’t be surprising when you consider how much life changes – both physically and emotionally – when someone can walk and move without pain.
Studies have consistently shown that hip and knee replacement are some of the most successful procedures in all of medicine when it comes to patient satisfaction and quality-of-life improvement. Most patients are able to resume activities that arthritis had made difficult, whether that be golfing, biking, caring for family members, or missing fewer work days due to pain.
Fortunately, long-term benefits of total joint replacement also include years of use. Other recent research has shown that 95 percent of hip replacements performed in the United States last 15 to 20 years, and 85 percent of knee replacements last two decades. In addition, improvements in surgical techniques, prosthetic designs, bearing surfaces, and fixation methods may allow implants to last even longer.
Types of joint replacement
Thanks to advancements in surgical techniques, prostheses, imaging, post-operative care and rehabilitation, many orthopedic surgeons are able to offer patients in need of joint replacement a variety of surgical options – depending on their individual situation and other factors like overall health, chronic disease and anatomy. Options often include:
- Posterior total hip replacement – This proven hip replacement method has a long-term track record of success. During this one- to two-hour surgery, a three- to six-inch incision is made over the damaged hip to expose deeper tissue. The damaged “ball” or head of the thigh bone (femur) is dislocated and removed. Damaged bone and cartilage in the “socket” are removed and the socket is smoothed and enlarged to receive the metal implant. A highly polished socket liner, which is usually made of polyethylene plastic, is secured inside the socket. The surgeon then creates a narrow, five-inch channel on top of the thigh bone to receive the new implant’s stem and ball. Materials in the new ball-and-socket joint press against one another easily to help restore hip motion.
- Anterior total hip replacement – This procedure is very similar to a posterior total hip replacement, except the surgeon accesses the hip joint from the front, as opposed to the back side (posterior) of the hip. This method has gained a lot of interest over the past decade and patients can generally expect an excellent outcome, as they can from the posterior approach.
- Revision hip replacement – After a period of normal wear and tear on an artificial hip joint, parts of the prosthesis may wear out or become loose. In these cases, hip revision surgery may be recommended. It is done to repair a prosthesis that has been damaged over time due to infection or normal wear and tear. Revision surgery helps correct the problem so the hip can function normally.
- Partial knee replacement – Also known as “unicompartmental knee arthroplasty,” this procedure is appropriate for people who are in good health and have exhausted conservative measures for managing knee pain. These patients may have had a torn meniscus (cartilage) or avascular necrosis (dead bone tissue) in the past that later led to arthritis in one part of the knee. For younger adults, a partial knee implant may be considered a bridge to surgically amend what can currently be repaired before further degeneration in the joint leads to the need for total knee replacement. Older adults may also be candidates, which is then expected to last the remainder of their lives.
- Total knee replacement – The implant usually consists of two parts made of chrome cobalt, titanium alloy and polyethylene plastic. The cobalt-chrome part is attached to the end of the thigh bone (femur) and a titanium alloy base plate is attached to the end of the leg bone (tibia). A polyethylene plastic “articulating” surface is then positioned between them. A polyethylene plastic “button” is attached to the undersurface of the knee cap (patella). Knee implants come in various sizes to fit every knee.
- Revision knee replacement – A knee replacement may fail over time for various reasons. If this occurs, a knee can become painful, swollen, stiff or unstable, making it difficult to perform everyday activities. If a knee replacement fails, your doctor may recommend a second surgery, called a revision total knee replacement. In this procedure, an orthopedic surgeon removes some or all of the original prosthesis and replaces it with a new one. Revision surgery is a longer, more complex procedure than total knee replacement. It requires extensive planning, as well as specialized implants and tools.
Improving your odds of success
No matter which joint replacement surgery may be most appropriate for any one patient, there are things people can do to help improve their odds of benefitting from a successful surgery, including:
- Losing weight, if necessary
- Quitting smoking
- Limiting alcohol use
- Muscle-strengthening exercises
- Making sure other medical conditions, such as diabetes, are under optimal control
Making a personal decision
Although an orthopedic surgeon can help you understand risks and benefits of joint replacement, only you can decide at what point pain and limitation of arthritis is affecting your quality of life enough to consider surgery. Understandably, the threshold where benefits outweigh risks is different for every patient.
Like every surgery, deciding whether to have joint replacement is – and should be – a very personal choice. Knowing that, my final recommendation is straightforward: Work with your doctor to fully understand the plan for managing your individual risk factors before and after joint replacement.
If that’s done well, there is a good chance that the long-term advantages of joint replacement surgery will outweigh the short-term risks.
He has a special interest in benign and malignant bone and soft tissue tumors, surgical treatment of sarcoma, limb reconstruction, total hip replacement, total knee replacement, revision hip and knee replacement, and partial knee replacement.
Dr. MacDonald practices at Virginia Mason Hospital and Seattle Medical Center.