Men have more complications after total knee, hip replacements

A new study - that for the first time looks at sex differences in outcomes - contradicts the idea that total joint replacement surgery is not performed as often in women because they tend to fare worse than men afterwards.

The researchers found women were less likely to have complications after total hip or knee replacement than men.

Total hip and total knee replacement surgery are common treatments for end-stage arthritis, a painful condition that limits mobility and diminishes quality of life.

The new study finds that while men tend to have their first total joint replacement at a younger age than women, they are more likely to have complications or need revision surgery.

The researchers at the University of Toronto, ON, Canada are presenting their findings this week at the 2015 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) in Las Vegas.

For their analysis, the team used data from patients who attended an Ontario hospital for a first total knee or total hip replacement between 2002 and 2009.

The data covered nearly 38,000 total hip replacements, 54% of which were in women, and nearly 60,000 total hip replacements, 60% in women.

Among the total hip replacements, female patients were significantly older than male patients (70 vs. 65 years) - while among the total knee replacements, there was no significant age difference (median was 68 years for both sexes).

More of the women who had total joint replacements were classed as frail compared to the men (6.6% vs. 3.5% respectively in the total hip replacements, and 6.7% versus 4.0% in the total knee replacements).

Post-op data shows men more likely to have complications

When they analyzed the postoperative data, the researchers found a number of sex differences in outcomes following total joint replacement surgery. For example, compared to women, men were:

• 15% more likely to visit the emergency department in the month following total hip or knee replacement
• More likely to have a heart attack in the three months following surgery (60% more likely after a total hip, 70% after a total knee replacement)
• 50% more likely to need revision surgery in the two years following a total knee replacement

The researchers say studies in North America show that despite the fact women tend to have more advanced arthritis in the knees and hips, they are less likely to undergo joint replacement than men, and that:

"One possible explanation is that women are less often offered or accept surgery because their risk of serious complications following surgery is greater than that of men."

Sex differences in outcomes do not explain disparities in take-up of surgery

However, this study shows that while the overall rates of serious complications following total knee and hip replacement were low for men and women, they were lower for women than for men - particularly in the case of knee replacement. 

"Thus, the previously documented sex difference utilization of TJR [total joint replacement] cannot be explained by differential risks of complications following surgery."

The researchers say future studies should aim to discover the reasons for these disparities.

According to the Centers for Disease Control and Prevention (CDC), arthritis is the most common cause of disability in the US, where it affects 52.5 million adults - more than 1 in 5.

The most common form of arthritis is osteoarthritis - a degenerative joint disease that most commonly affects the knees, hips, hands and spine. The disease develops as tissue in the joints breaks down, leading to pain and stiffness.

There is currently no cure for osteoarthritis, so treatments - including joint replacement surgery - focus on relieving symptoms and improving function.

In the US, nearly 1 in 2 people may develop symptomatic knee osteoarthritis by the age of 85, and 1 in 4 people may develop painful hip arthritis in their lifetime.

Most total joint replacements are for osteoarthritis - although a relatively small proportion can also be for rheumatoid arthritis.

There were 232,857 total hip replacements and 454,652 total knee replacements, primarily for arthritis, in the US in 2004, the most recent year for which figures from the CDC are available.

References:

1.  Sex-related differences in morbidity and mortality following total hip and knee arthroplasty, Bheeshma Ravi, et al., presented 26 March 2015 at AAOS 2015 Annual Meeting, abstract.
2.  AAOS news release, accessed 26 March 2015.
3.  CDC Arthritis, accessed 26 March 2015.