Rate of Lower Extremity TJA for Patients With Rheumatoid Arthritis Remain Stable

Patients with rheumatoid arthritis (RA) have a proliferative synovitis, which results in destruction of articular cartilage and bone, most commonly in the hips and knees. Lower extremity total joint arthroplasty (TJA) has been successful in improving functional outcomes in these patients. During a poster presentation at the AAOS 2018 Annual Meeting, researchers from the Cleveland Clinic presented their study, which evaluated the annual trends of patients with RA who underwent lower extremity TJA, specifically total hip arthroplasty (THA) and total knee arthroplasty (TKA).

Using the Nationwide Inpatient Sample, researchers identified all patients with RA who underwent THA (n=90,487) and TKA (n=209,332) between 2002 and 2013. During that time period, the U.S. population increased from approximately 288 million to 316 million.

The annual number of TKAs in patients with RA increased by 93.1% (from 11,618 to 22,430), and the annual number of THAs in this population increased by 59.3% (from 5,764 to 9,180). The incidence of TKAs in RA increased from 5.4 to 9.2 TKAs per 100,000 U.S. adults (95% CI 1.05-1.05; p<0.001), and the incidence of THAs in this population increased from 2.7 to 3.8 THAs per 100,000 U.S. adults (95% CI 1.04-1.04; p<0.001).

The annual prevalence of RA in patients who underwent lower extremity total joint arthroplasty was 31.5 per 1,000 THAs in 2002 and 32.8 per 1,000 THAs in 2013 (p=0.06). The annual prevalence of RA in those who underwent THA did not significantly change over the specified time period, with 28.6 per 1,000 THAs in 2002 and 28.6 per 1,000 THAs in 2013 (p=0.200). This was also true in those who underwent TKA, with 33.2 per 1,000 THAs in 2002 and 35 per 1,000 THAs in 2013 (p=0.095).

“The rates of lower extremity TJA performed in [patients with] RA has remained relatively stable over the past decade,” the authors concluded, noting that this is most likely related to the introduction and use of disease-modifying antirheumatic drugs.