Research Summary

Feasibility Trial Finds RCT of One- vs Two-Stage Knee Revision for Prosthetic Joint Infection Not Achievable Under Current Design

Kate Young

Key Highlights

  • Recruitment to a randomized controlled trial (RCT) comparing one-stage versus two-stage revision knee surgery for prosthetic joint infection (PJI) proved infeasible, with only 3 patients randomized from 136 screened.
  • Major barriers included complexity of patient cases, surgeon and patient preferences, and COVID-19–related disruptions.
  • Qualitative data underscored the influence of patient trust, surgeon equipoise, and challenges of trial design in this setting.
  • Findings suggest alternative study designs (e.g., platform or cluster trials) are needed to address this important clinical question.

The MIKROBE feasibility study sought to determine whether a randomized controlled trial could be conducted to compare one-stage versus two-stage revision knee surgery for prosthetic joint infection. Despite careful planning, recruitment was extremely limited: only 3 participants were randomized out of 136 screened. These results clearly indicate that, under the current design, a large-scale RCT is not feasible.

Prosthetic joint infection after total knee replacement is a devastating complication, affecting approximately 1.1% of patients within 2 years of surgery. Revision strategies typically involve either one-stage or two-stage approaches. Although reinfection rates are similar, there remains clinical uncertainty regarding functional outcomes, patient burden, and healthcare costs. This study was initiated to test whether a definitive trial could address these questions.

The study was conducted across four UK high-volume revision centers. Patients with PJI deemed suitable for either approach were invited to participate. Following informed consent and an audio-recorded consultation with a surgeon, randomization to one-stage or two-stage revision was performed on a 1:1 basis. Patient-reported outcomes were collected at baseline and at 3 and 6 months, and embedded qualitative research explored experiences of patients and surgeons with trial processes and decision-making.

Between July 2020 and October 2022, 136 patients were screened. Only five consented, and three proceeded to randomization—two to one-stage surgery and one to two-stage. Limited follow-up data were obtained, with only one participant completing 3- and 6-month postoperative questionnaires. Barriers to recruitment included patients’ reluctance to defer surgical choice to randomization, surgeons’ pre-existing preferences, and the complexity of referred cases. The COVID-19 pandemic also reduced case numbers and disrupted pathways, further limiting recruitment. Qualitative interviews revealed important themes: patients valued shared decision-making and surgeon guidance over computer-based randomization; surgeons highlighted dissonance between empirical uncertainty and ingrained practices; and both groups recognized the severe physical, social, and psychological burden of PJI.

The primary limitation was the extremely small sample size, precluding meaningful statistical or cost-effectiveness analyses. COVID-19 disruptions, variability in patient pathways, and concentration of complex cases at referral centers further reduced feasibility.

“This study indicated that a larger randomized controlled trial evaluating one-stage versus two-stage revision knee surgery for prosthetic joint infection is not feasible with the current straightforward randomized controlled trial design,” the authors concluded. “Future research needs to consider the most appropriate study design and methodology to address this important research question.”

Reference:
Terry R, Dean S, Hourigan P, et al. MIKROBE: a feasibility study for a randomised controlled trial of one-stage or two-stage surgery for prosthetic knee infection. Pilot Feasibility Stud. 2025;11(1):49. Published 2025 Apr 16. doi:10.1186/s40814-025-01634-4