For periprosthetic joint infections (PJIs) following primary hip or knee arthroplasty, a two-stage approach has been considered the gold standard of treatment in the United States. However, that method requires two surgeries—one to allow the infection to heal followed by a second to install a new prosthesis—potentially increasing patient costs and inconvenience. The reported success rates are variable, ranging from 70 to 90 percent.

Some European studies show that a one-stage approach leads to lower reinfection rates and is less costly for the healthcare system. Unfortunately, studies of the one-stage approach are difficult to interpret because they were underpowered; lacked comparator groups receiving the two-stage approach; or excluded patients with chronic PJIs, comorbidities, resistant organisms, or draining sinuses.

To provide clarification, researchers designed a multicenter, randomized, comparative clinical trial to compare one-stage with two-stage treatment for PJI. The trial included all patients regardless of comorbidities, resistant organisms, or draining wounds. Presented at the 2024 American Association of Hip and Knee Surgeons Annual Meeting, the 2-year data demonstrate that one-stage and two-stage treatments of PJI have similar success rates—98 percent success for one-stage treatment versus 91 percent for two-stage.

“Currently, the main reason for the revision of prosthetic knees or hips is infection,” said lead investigator Thomas K. Fehring, MD, FAAOS, codirector of the OrthoCarolina Hip and Knee Center and director of the OrthoCarolina Periprosthetic Joint Infection Center. “It is a significantly debilitating process, difficult to treat, and the success rate for two-stage treatment is not optimal. My whole career I’ve used two-stage treatment for PJI, but we needed a prospective, randomized study on one-stage versus two-stage treatment to determine which was superior for our patients. These 2-year data suggest that one-stage treatment is comparable to two-stage treatment, provided the specific protocol in our study is followed.”

Funded by the Orthopaedic Research and Education Foundation, the study enrolled 323 patients with chronically infected joints (212 knees, 111 hips) at 14 dedicated trial sites, with 52.5 percent of patients enrolled at one site (OrthoCarolina). Patients were randomized to one-stage (n = 166) or two-stage treatment (n = 157). Exclusion criteria included fungal infection, immunosuppression, extensive soft-tissue defect, and revision. In their statistical power analysis, the authors predicted a 10 percent rate of loss to follow-up. After taking into account deceased patients and an actual 9.3 percent loss to follow-up rate, the final data set included 254 patients—133 one-stage and 121 two-stage patients.

Patients in both cohorts underwent a double surgical setup, similar irrigation protocols, an initial 6-week course of IV antibiotics, 6 months of oral antibiotics after reimplantation, and 1 gram of vancomycin powder at reimplantation. The one-stage and two-stage groups were similar with respect to demographics and Musculoskeletal Infection Society classification.

In a regression analysis, after the researchers adjusted for comorbidities and resistant organisms, one-stage treatment had nearly 4.5 times the odds of success and nearly four times the odds of success when the researchers adjusted for draining sinus. The results indicate that the one-stage approach is statistically non-inferior to two-stage treatment for chronic PJI of primary implants.

“This trial was protocol-driven—similar surgical protocols, similar irrigation protocols, and similar antibiotic regimes intraoperatively and postoperatively,” Dr. Fehring said. “Additionally, the importance of a double surgical set cannot be overemphasized, including re-prepping and re-draping after the infected extraction instruments are removed from the room.”

The study had several limitations, such as potential selection bias due to significant enrollment variability at the sites, as OrthoCarolina contributed 52.5 percent of patients. However, the results were similar across all participating sites. Dr. Fehring concluded, “Because one-stage treatment was shown to be non-inferior to two-stage treatment in the trial, one-stage treatment may be best for the patient and the healthcare system at this time.”

Molly Todd Rudy is a freelance writer for AAOS Now.