By Las Vegas Health
Gary Wacker describes his decision to have joint replacement surgery as “a no-brainer.”
“I was failing fast,” Wacker said. “I got to the place were climbing stairs hurt like the dickens, and climbing ladders was unbearable. I had an instance where I had to grit my teeth to climb a one-story ladder.”
Wacker is a refrigeration mechanic, often requiring him to crawl on his hands and knees, climb ladders and lift heavy objects. He had both hips replaced in December 2006, and now he says he feels “wonderful.”
“At 53, I don’t feel like I’m 18 again, but I didn’t expect to,” Wacker said. “I can pretty much do anything I could do before this problem.”
More than 800,000 people in the U.S. had knee and hip replacement procedures in 2007. That number is expected to rise, according to the American Academy of Orthopaedic Surgery (AAOS). Of the two major joint replacement categories, about 500,000 procedures were for knee replacements, while 300,000 patients received hip replacements. Other joints such as elbows and shoulders can be replaced as well, but these procedures are less common.
In a healthy joint, bones are separated by layers of soft tissue called cartilage that absorb impact and prevent bones from rubbing against one another. Joint replacement is a surgical procedure in which damaged cartilage and bone are removed and replaced with synthetic components to relieve pain and regain range of movement. It can be used as a treatment for severe arthritis as well as injury involving joints, such as those sometimes sustained by athletes.
“The vast majority of patients need a joint replacement for disabling pain as a result of arthritis,” said Dr. Scott Cooper, an orthopaedic surgeon at Ozark Orthopaedics in Rogers.
Joint replacements are meant to last for long periods of time, but age can affect the need for a procedure to be performed more than once during a patient’s lifetime.
“Speaking of hip replacements and knee replacements, well over 90 percent last for 10 years, probably 75 percent or so will last for 20 years, but they don’t last forever and the younger a patient is when they get one, the more likely they are to wear it out,” Cooper said.
In the past, the procedure was primarily used in older patients, but new developments in materials and technology have made joint replacement safer and more attractive to people that may not have considered it before.
The increase in joint replacement procedures is the result of new developments in prosthetic joints and a widening segment of the population receiving the operations, according to Dr. James Stiehl, clinical associate professor at the Medical College of Wisconsin.
“These devices have eliminated the issue of wear that we’ve dealt with for years,” Stiehl said, referring to cross-linked polyethylene. This highly-versatile and wear-resistant thermoplastic is the same basic material used in flexible home piping.
Older prosthetic joint materials are prone to heavy wear and breakage, but studies of cross-linked polyethylene show significant improvements in these areas. This new development means more people are able to undergo joint replacement surgery than ever before. With older metal-on-metal applications, doctors must deal with the long-term effects of microscopic metal shavings entering the blood and poisoning the patient. At particular risk are patients with kidney ailments and pregnant or nursing mothers. Because the new cross-linked polyethylene is more wear-resistant, joint replacements are now safer for patients in such sensitive situations.
More younger patients are also getting joint replacements. While the average age of a joint replacement patient is about 66, about a third of joint replacement patients are younger. These younger patients are attracted to newly-developed prosthetic joints because of their longer life and decreased wear. Younger patients tend to be more active, increasing the risk of prosthetic joints wearing out prematurely, but with newer materials, this risk is greatly diminished.
Another driving force behind the increase in joint replacements is the development of new techniques that make the procedure less invasive. By using special tools designed to work through smaller incisions, surgeons can accomplish the same results with less trauma to the body, shortening the time required for healing. This technique is referred to as “minimally invasive,” but Stiehl warns minimally-invasive procedures can increase the chances of complications because of the difficulty of such operations.
In 2006, the Food and Drug Administration approved another technique that is meant to spare as much natural material within the joint as possible. The technique is known as hip-resurfacing, and it involves rounding the head of the femur and placing a synthetic cap over it to replace damaged cartilage. The benefits of this procedure include preserving the natural stability of the bone and more natural movement of the joint. Having only been on the market for a couple of years, the lifespan of these implants is still a subject of research.
Because of the procedure’s relatively untested track record, some doctors are wary of performing the operation.
“Hip resurfacing is a reasonable approach, but there are some problems,” Stiehl said.
At the time of FDA approval, most of these implants were metal-on-metal applications, limiting their use in patients that may be sensitive to metal ions. There is also a risk of femoral neck fracture. Patients with osteoporosis are not good candidates for hip resurfacing, and this eliminates many women and senior citizens, groups most likely to develop the bone-weakening condition. Still, hip resurfacing is performed in a number of hospitals nationwide.
With these new materials and techniques improving joint replacement and opening it to much wider audiences, what does the future hold? Stiehl looks to computers to further improve what is already a widely-successful procedure. Computer-assisted surgery has the potential to reduce tissue trauma by reducing the time and cutting required for each operation.
“We just have to look at ways to make it more predictable,” Stiehl said. “I think the computer is going to add precision to these operations to make them easier to do.”
Joint replacement is certainly not a risk-free procedure, but the success rate of such operations is between 95 percent and 99 percent.
Cooper said one of the risks is developing an infection,
“Infection is a risk of any operation, but it’s particularly bad if a joint replacement becomes infected because usually that requires removal of the implants and having the patient get I.V. antibiotics for several weeks before the implants can be put back in,” he said.
The most serious risks include infection and blood clots, but Stiehl put the risk of either occurring at less than 1 percent. Other risks include bone fracture, limb length inequality, prosthetic loosening and risks associated with any surgical procedure, such as heart attack or stroke.
“Things that impact these numbers are things like hospital experience,” Stiehl said. “Hospitals that do more than 250 joints a year have lower rates of complications. It stands to reason, the better you are, the lower your complications.”
Wacker says he would recommend the surgery to others in similar situations.
“The rehab involves discomfort, stretching yourself and a lot of downtime,” Wacker said. “But, if you have serious joint pain, I would definitely recommend having it done.”

Antoinette Grajeda contributed to this report.