Risk Factors for Revision Surgery Following Revision Total Knee Arthroplasty Using a Hinged Knee Prosthesis for Septic and Aseptic Indications.

INTRODUCTION: The use of hinged knee replacements (HKRs) for limb salvage is a popular option for revision total knee arthroplasty (RTKA). Although recent literature focuses on the outcomes of HKR for septic and aseptic RTKAs, little is reported on the risk factors of returning to the operating room. The purpose of this study was to evaluate risk factors of revision surgery and revision after receiving HKR for septic versus aseptic etiology. METHODS: A multicenter, retrospective review was conducted on consecutive patients who received HKR from January 2010 to February 2020 with a minimum follow-up of 2 years. Patients were separated into two groups: septic and aseptic RTKAs. Demographic, comorbidity, perioperative, postoperative, and survivorship data were collected and compared between groups. Cox hazard regression was used to identify risk factors associated with revision surgery and revision. RESULTS: One-hundred fifty patients were included. Eighty-five patients received HKR because of prior infection, and 65 received HKR for aseptic revision. A larger proportion of septic RTKA returned to the OR versus aseptic RTKA (46% vs 25%, P = 0.01). Survival curves revealed superior revision surgery-free survival favoring the aseptic group ( P = 0.002). Regression analysis revealed that HKR with concomitant flap reconstruction was associated with a three-fold increased risk of revision surgery ( P < 0.0001). DISCUSSION: HKR implantation for aseptic revision is more reliable with a lower revision surgery rate. Concomitant flap reconstruction increased the risk of revision surgery, regardless of indication for RTKA using HKR. Although surgeons must educate patients about these risk factors, HKR remains a successful treatment option for RTKA when indicated. LEVEL OF EVIDENCE: prognostic, level III evidence.