A one-stage revision technique for periprosthetic joint infection (PJI) after a total hip replacement or total knee replacement may offer lower cost, quicker restoration of function, and lower morbidity than a two-stage revision; further, it may also lead to equivalent infection eradication compared to a two stage revision, according to a new study by researchers at Hospital for Special Surgery in New York City. The research will be presented at the upcoming annual meeting of the American Academy of Orthopedic Surgeons, March 12-16 (poster #514)

"In our study, we have shown no significant difference in terms of infection cure rate at a mean of two years postoperative, in our select group of patients, between the one-stage and two-stage revision," said lead study author Michael B. Cross, MD, an orthopedic surgeon specializing in hip and knee replacement at HSS. "This study provides good preliminary data to support a randomized trial and that is ongoing [in the U.S.]."

PJI is one of the most devastating and frequent complications after lower extremity joint replacement, often requiring revision surgery. "Infection is the hardest complication of joint replacement for both surgeon and patient," said Dr. Cross. For the patient, infection requires additional surgery and time off work, and there is a constant fear that the infection won’t be cured. Revision surgery can be tricky for surgeons.

Traditionally, surgeons have treated infected knee replacements with a two-stage approach, by removing the implants and inserting an antibiotic spacer to treat the local infection. After the knee is retested and free of infection, the knee implant is reinserted. The infection cure rate with this technique is 85%, and the process takes roughly three months at a minimum, which is a long time for patients to be out of work and not active. Another option used more frequently in Europe and for select cases in the United States, is a one-stage process, where the implant is removed, the knee joint is depleted of infected tissue and the knee replacement is put back in with a whole new set of sterile instruments. Critics of the one-stage technique have suggested that infection eradication is inferior to the historically successful two-stage revision. 

To shed light on the issue, researchers at HSS conducted a retrospective, case- control study to compare infection-free and all-cause revision survival between a matched cohort of one-stage and two-stage revisions for PJI. They identified 41 patients who underwent a one-stage revision for a PJI after a total hip or knee replacement through an IRB-approved database at HSS. Patients were matched (1:2) to controls treated with a two-stage revision, based on joint, sex, and body mass index.

With an average follow-up of 2.6 years, infection-free survival was not statistically or clinically significant, 80.5% in the one-stage group and 87.8% in the two-stage group (P=0.28). All-cause revision survival was 70.7% for one-stage and 75.6% for two-stage revisions (P=0.56), but 31.7% of two-stage patients had a history of revision in the affected joint compared to none of the one-stage patients (P<0.01). To control for this, survival was assessed for 41 one-stage and 56 two-stage patients with no history of revision in the affected joint. Infection-free survival (80.5% vs 92.9%; P=0.07) and all-cause revision survival (70.7% vs. 80.4%; P=0.27) were not different between subgroups. The reduced duration treatment and a single operation with the one-stage revision reduces cost and morbidity, in addition to being more convenient.

To the authors’ knowledge, the study is the first to compare one-stage and two-stage procedures, while controlling for previous replacement procedures and also the first to control patient population between two groups at a single institution. "It’s usually a hospital in Europe publishing data on a one-stage and a hospital in the United States publishing data on a two-stage, but obviously there is different bacteria and different hospital settings, so the comparison between the two is not as good," said Dr. Cross. "On average, there was a better success rate to treating the infections with the two-stage revision, but statistically it was not different between the two groups."

Dr. Cross noted that joint replacements are becoming more common, as the baby boomer generation ages and starts requiring more care for hips and knees. "The baby boomers are more active in their generation, and as a result of that, there is a huge influx in demand for hip and knee replacements," said Dr. Cross. "Knee replacements are growing exponentially, and they will continue that way until 2030."