Functional Articulating Antibiotic Spacers for Chronic Native Septic Knee Arthritis

Area of Science:

• Orthopedic Surgery
• Infectious Disease
• Biomaterials Science

Background:

• Semipermanent functional spacers are used for prosthetic joint infections to avoid repeat surgeries.
• This study evaluates metal-on-polyethylene articulating spacers for chronic native septic knee arthritis.

Purpose of the Study:

• To assess the efficacy of metal-on-polyethylene articulating spacers in treating chronic native knee septic arthritis.
• To compare functional outcomes between different spacer constructs and treatment approaches.

Main Methods:

• Retrospective review of 18 patients with chronic native knee infection treated with articulating antibiotic spacers.
• Analysis of spacer construct type (all-polyethylene vs. polyethylene inserts), complications, infection eradication, and functional results using Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR).

Main Results:

• 44% all-polyethylene tibial components and 56% polyethylene inserts (PI) were used.
• 28% of patients experienced spacer complications.
• 67% underwent reimplantation, while 33% retained their spacer long-term.
• The PI group showed better KOOS JR scores; the reimplantation group met both minimum clinically important difference (MCID) and patient acceptable symptom state (PASS) criteria, while the retained spacer group met MCID but not PASS.

Conclusions:

• Functional articulating spacers are a viable treatment option for chronic native knee septic arthritis.
• Polyethylene insert spacers demonstrated improved functional outcomes without increasing reimplantation rates.
• Both planned two-stage reimplantation and long-term spacer retention present promising solutions for managing this challenging condition.