Patients with rheumatoid arthritis were at higher risk than those with osteoarthritis for adverse outcomes following joint replacement surgery, a Canadian study found.

After adjustment for potential confounders, having a diagnosis of rheumatoid arthritis was a significant and independent predictor of dislocation following total hip arthroplasty, with a risk almost double that for osteoarthritis (HR 1.91, 95% CI 1.29-2.82, P=0.001), according to Bheeshma Ravi, MD, of the University of Toronto, and colleagues.

Patients with rheumatoid arthritis also were at greater risk for developing an infection after total knee arthroplasty (HR 1.52, 95% CI 1.11-2.09, P=0.03), the researchers reported online in Arthritis & Rheumatism.

"Over the last decade, the age-sex standardized rates of total hip arthroplasty and total knee arthroplasty have increased in North America by approximately 25% and 65%, respectively," wrote Ravi and colleagues.

These surgeries have been linked with a risk -- albeit small -- for serious complications including dislocation, infection, venous thromboembolism, and even death.

However, most data on these complications have been drawn from the patient population with osteoarthritis, and little is known about risks for those with rheumatoid arthritis, a much different disease in its causes, prognosis, and treatment.

The researchers previously conducted a systematic review and meta-analysis in an effort to fill this knowledge gap, but were hampered by limitations in many studies such as the possibility of diagnostic misclassification and lack of adjustment for confounders.

Therefore, they undertook a study in which they analyzed data from the Canadian Institute for Health Information Discharge Abstract Database, identifying patients with a primary elective hip or knee replacement between April 2002 and March 2009.

Continue reading...