How long implants last in people with juvenile idiopathic arthritis (JIA) who had joint replacement surgery depends on disease type, year of surgery, number of complications, and medication use before and during these procedures, a study reported.
Results also showed an upward trend in the age of JIA patients needing implants, as well as in disease duration before surgery.
The study, “Early joint replacement in juvenile idiopathic arthritis (JIA): trend over time and factors influencing implant survival,” was published in the journal Arthritis Care & Research.
JIA is characterized by swelling in the joints, pain, and stiffness in the knees, hands, or feet.
The goal of therapy is to halt disease progression and prevent joint damage. However, in disease types at a high risk of joint damage, such as polyarticular and systemic JIA, medical treatments can fail. The only option for those with severely damaged joints is a total joint replacement, or arthroplasty.
The inflammatory nature of JIA, which can affect bone quality, also can carry short- and long-term consequences for those undergoing such surgery.
A team of researchers based in Milan, Italy, analyzed the medical records of all JIA patients who underwent total joint replacement at the local Gaetano Pini Hospital from 1992 to 2019.
Their goal was to detail patients’ demographic and clinical features, including the number and type of implants. Additional objectives included the rate of complications and implant survival (longevity).
A total of 85 JIA patients were included, with a median follow-up of 17.2 years. A first surgical procedure was done on patients ranging in age from 14 to 46; the median age was 22.7.
Thirty-seven patients had the polyarticular form of JIA (pJIA), 24 were systemic JIA patients, 16 had oligoarticular disease, and eight were classified as “other.”
Among these JIA categories, age at surgery, disease duration before surgery, number of implants, and rate of complications were not significantly different.
A total of 198 joint replacement surgeries were given over 27 years, with most patients (78%) receiving more than one implant. Among these procedures, 121 were hip replacements, 66 were knee surgeries, and 11 were done on the ankles. The hip was also the first joint be replaced for most of these people, 83%.
The overall rate of complications was 13%, involving 25 surgeries in 20 patients, including eight fractures during surgery and three infections. Fourteen patients experienced insufficient integration or wear of the bone implant (aseptic mobilization).
Most received steroids throughout their disease, particularly patients with sJIA (82%) compared with people with pJIA (69%). Disease-modifying anti-rheumatic drugs (DMARDs) were being used by 80% of patients, while 30 (35%) had at least one biological therapy before the first surgery.
A significant difference was seen in the age at first surgery before the year 2000 (nearly 22 years old), compared with procedures done between 2000 and 2010 — about 27 years old — and after 2010 (average age of 28). The same trend was found for disease duration before surgery, i.e., a difference of about six years.
According to the investigators, the availability of Amgen‘s Enbrel (etanercept) across the European Union starting in 2000 may have influenced the delayed age at first surgery. Enbrel is an anti-inflammatory biologic therapy.
Implant survival at five, 10, and 15 years ranged between 84% and 89%. Half of the implants given lasted 20 years or more. Compared those sJIA patients, implants in people with pJIA lasted longer.
A statistical analysis found that the year of surgery was significantly related to implant survival, as was the presence of complications.
Prolonged treatment with biologics before surgery predicted poor implant survival, while steroid treatment at the time of surgery predicted more favorable implant outcomes.
“We observed a progressive and significant upward trend of both age at arthroplasty and disease duration before the first arthroplasty over time,” the scientists wrote. “JIA category, year of surgery and presence of complications significantly affected implant survival.”