Joint replacement: a success story

Toronto orthopedic surgeon Dr. Rod Davey calls joint replacement surgery “happy work.” Not only is it the most cost effective surgery of any performed — a total hip replacement costs the system $10,000 and improves the patient’s quality of life for 15 years — but the success rate is more than 95 per cent. That’s a lot of happy customers out of the 45,000 people who get joints replaced in Canada every year, says Davey, who heads up orthopedic surgery at the University Health Network.

Thelma Nichol, a 78-year-old retired teacher from North Bay, Ont., is one of them. She had her first replacement 13 years ago when Davey replaced her right hip. In the next five years, she had her second hip and both knees replaced as her arthritis progressed (she suffers from both osteoarthritis and rheumatoid arthritis). The surgeries gave her life back to her. Before her first surgery, she endured intense pain and used a wheelchair. “Now I charge all over,” she says. The only glitch so far was when her oldest replacement joint – the right hip – popped out of its socket a few years ago, causing her severe pain and some tissue damage and landing her back in hospital for repair work ∓8211; or a revision, as surgeons call it. But at her last checkup, Davey told her all four joints are fitting as tightly as the day they were put in. Nichol takes some credit for that – she has been careful to follow her doctor’s orders, avoiding any jerky movements and awkward positions.

Nichol’s replacement joints have allowed her and her husband to indulge their passion for travel. They’ve crossed Canada from St. John’s to Victoria, visited most of Europe and taken an Alaskan cruise. “I’m able to keep up,” she says. She carries two cards in her purse to hand to airport security – one stating she has metal knees and the other, metal hips.

Having four metal joints only stops Nichol from doing two things – she had to give up lying in a hot bath in favour of showering standing up. And, a practising Anglican, she can no longer kneel to take communion and has to stand instead. But she’s definitely not complaining, she says.

In a way, joint replacement surgery has become a victim of its own success. Demand is high, and waiting lists are excruciatingly long as anyone waiting for a new hip or knee knows only too well. While Nichol waited eight weeks for her first hip replacement in 1992, patients in Ontario are now waiting an average of four months for a new hip and more than six months for a new knee. Waits of more than a year are not unheard of. And the queue is only expected to get longer as aging boomers start discarding arthritic joints for pain-free ones made of titanium and polyethylene plastic.

The vast majority of joint replacements are done because the cartilage in the joint has deteriorated as a result of osteoarthritis so that bone is hitting on bone with each painful step. Cartilage is the material that protects the ends of bones – “Think of the smooth white covering over the ends of chicken bones,” says Davey. Cartilage can crack and split with use, which is why osteoarthritis is called a wear-and-tear disease. But it’s not a simple correlation between use and deterioration. No one knows why some people develop osteoarthritis and others don’t. But what we do know, says Davey, is that once osteoarthritis starts, it progresses through time so a bad joint just keeps getting worse although the rate of deterioration varies, which is why some people need new hips sooner that others.

Without surgery, all that can be done is to treat the pain symptoms with non-prescription and prescription painkillers. Sufferers can also reduce activities or use a cane or brace to take pressure off the offending joint. Weight loss of 20 or 30 pounds can help for those who are overweight since symptoms are in proportion to body weight, Davey says.

But eventually someone with painful osteoarthritis has to make the decision whether to replace the joint rather than treat the pain. And with improved technology to make the surgery much less invasive and therefore allow older candidates and those with other health issues such as heart disease to choose replacement, more and more people are opting for surgery. Someone who may not have been a candidate for surgery 15 years ago may be a candidate now, Davey says.

Next page: If replacement surgery is in your future…

If replacement surgery is in your future, here’s what’s available in artificial joints
Metal ball and polyethylene plastic cup
The majority of surgeries in Canada are done using metal-and-poly joints. While results are excellent, these joints do have drawbacks. When the poly wears down over time, tiny particles migrate into the bone, causing osteolytis, or softening of bone tissue. The strength of the poly has improved considerably, reducing the incidence of wear.

artificial joints are now becoming available. When first introduced in the 1950s, they were unsuccessful because the technology couldn’t match the ball and socket. However, new computer technology produces much higher tolerances. These joints are more expensive but are appropriate for younger active patients who need a new hip to last 25 years. These joints are only available for hips at the moment.

Ceramic-on-ceramic joints
These are “a little controversial,” Davey says. While problems associated with plastic are eliminated, ceramic has the potential to shatter on impact, which is a concern in case of accidents.

Here’s what’s new in treatment and recovery
Minimal invasive surgery
Instead of the eight- or nine-inch incisions that surgeons routinely used to access a joint a few years ago, three- or four-inch incisions are the standard. Surgeons use special instruments to retract muscles rather than cutting through them. The result is a quicker rehabilitation and a much better cosmetic effect although the surgery doesn’t make any difference to long-term results.

Better materials
When surgeons replace a ball-and-socket hip joint, they cut off the two ends of bone and insert the ball attached to a stem, which is then inserted into the femur. The socket is attached to pelvis with bone cement. In the past, the stem end was cemented in place in the femur. Now, most procedures are done without cement. Instead, bone is allowed to grow around the stem to hold it in place. The advantage is that the stem is more secure over the long term and, therefore, lasts longer. Older patients in their 80s are usually offered cemented joints because the joint “is not asked to last as long,” says Davey.

Computer-assisted surgery
New software and image-guided surgery cameras help surgeons navigate joints by pinpointing the position of their instruments within the joint on a monitor. This improves accuracy and, therefore, results. According to Dr. Nizar Mahomed of the University Health Network, who is one of a handful of surgeons now performing the surgery, the benefits include potentially longer lasting implants. Using this technology increases the duration of surgery and, therefore, the costs. But long-term benefits will eventually outweigh these costs; within the next five to 10 years, computer-assisted surgery will be the norm in Canada, Mahomed expects.

Repairing old work
Nine per cent of surgeries to replace hips and knees are repairs on earlier replacements. Hips are more likely to require repair than knees. The most common reason for revision surgery is loosening of the joint, followed by osteolytis and poly wear. The Canadian Joint Replacement Registry recently published a study that showed that revision surgery resulted in longer hospital stays that primary surgery. Doing it right the first time is becoming more and more important to save costly operating time and reduce waiting lists.

Hip resurfacing
When Premier Ralph Klein announced Alberta’s so-called Third Way approach to health care, he commented that all patients would have access to basic procedures but they could opt to pay more for deluxe procedures “like the Birmingham hip.” In fact, in several provinces, the hip resurfacing procedure known as the Birmingham hip (it was pioneered by a group of surgeons in Birmingham, U.K.) is already covered by provincial health care although only a few surgeons perform the procedure. In hip resurfacing, the ball of the hip is fitted with a metal cover used with a metal socket. The procedure reduces the risk of osteolytis and is less invasive to the femur bone, which could be important if a revision was needed in the future. The main drawback of hip resurfacing is its short track record. Since it has only been available for less than a decade, long-term results are not known.