Clinical Scorecard: Evaluating the Efficacy of "Off-Label" DAIR-Plus and Partial Two-Stage Exchange for Treating Chronic Infections in Knee Megaprostheses
At a Glance
Category
Detail
Condition
Chronic periprosthetic joint infections (PJI) in knee megaprostheses
Key Mechanisms
Infection due to large implant surface, soft tissue damage, immunosuppression, and compromised patient health; surgical treatment involves DAIR-Plus or partial two-stage exchange retaining stems
Target Population
Patients with chronic PJI of knee megaprostheses including distal femur, proximal tibia, and total femur reconstructions
Care Setting
Specialized orthopedic surgical centers with expertise in megaprosthesis infection management
Key Highlights
PJI rates in megaprostheses range from 15% to 40%, higher than conventional total joint arthroplasties.
DAIR-Plus and partial two-stage exchange retain well-fixed stems to reduce bone loss and complex reconstruction risks in chronic knee megaprosthesis infections.
Treatment success is evaluated by PJI-free survival at 1, 2, 5, and >5 years, with failure defined as amputation or chronic suppressive antibiotic therapy.
Guideline-Based Recommendations
Diagnosis
Diagnose PJI using International Consensus Meeting (ICM) 2018 criteria: one major criterion or score ≥6.
Confirm diagnosis preoperatively with joint aspiration and intraoperative cultures (minimum five samples).
Exclude acute PJI (<6 weeks from index surgery or <7 days from symptom onset).
Management
Use DAIR-Plus (debridement, antibiotics, irrigation, implant retention plus removal of mobile components) for chronic PJI with well-fixed stems.
Consider partial two-stage exchange (removal of modular components, retention of stems, cement spacer placement) especially with sinus tract or poor soft tissue conditions.
Reserve complete implant removal for cases where stem retention is not feasible or unsuccessful.
Follow patients for a minimum of two years to assess infection resolution.
Define treatment failure as need for amputation or chronic suppressive antibiotic therapy.
Risks
High risk of reinfection due to large implant surface and compromised soft tissue coverage.
Potential bone loss and extensor apparatus damage with stem removal.
Increased complications in oncology patients due to immunosuppression and radiotherapy effects.
Patient & Prescribing Data
Patients with chronic knee megaprosthesis PJI undergoing DAIR-Plus or partial two-stage exchange with stem retention.
DAIR-Plus is selected for well-fixed stems and identified microorganisms; patient preference and intraoperative findings influence treatment choice; partial two-stage exchange preferred with sinus tract or poor soft tissue.
Clinical Best Practices
Preoperative imaging to confirm well-fixed stems before DAIR-Plus or partial two-stage exchange.
Obtain multiple intraoperative cultures to guide antibiotic therapy.
Tailor surgical approach based on soft tissue condition, presence of sinus tract, and microorganism identification.
Ensure minimum two-year follow-up to evaluate infection control.
Inform patients thoroughly about treatment options and risks, respecting their preferences.
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