Study supports direct infusion of antibiotics for single-stage TKA revision
Direct intra-articular infusion of vancomycin delivered to the infected joints of patients who undergo one-stage revision total knee arthroplasty provides more effective antibiotic delivery than loaded cement spacers, according to a presenter at a recent meeting.
“The classic technique is a cement spacer delivering intra-articular antibiotics. But unfortunately, cement spacers only deliver about 1% to 15% [of antibiotic], and that is usually over the first 3 days because it diffuses only from the outer surface,”
Direct infusion study
Whiteside cited a 2011 study in which he and colleagues followed 18 patients with methicillin-resistant Staphylococcus aureus (MRSA) who underwent single-stage, uncemented revision total knee arthroplasty that incorporated direct, intra-articular infusion of 500 mg of vancomycin using Hickman catheters up to twice a day for 6 weeks. The catheters feature, “a fibrous cuff that allows soft-tissue ingrowth and seals the surface of the tube to prevent contamination of the joint by tracking along the catheter,” Whiteside wrote in his abstract. The researchers maintained serum vancomycin levels between 3 µg/mL and 10 µg/mL. Using measurements in two knees, the researchers found peak synovial fluid peak concentrations were 10,233 µg/mL and 20,167 µg and trough vancomycin levels of 724 µg/mL and 543 µg/mL, respectively. The patients were followed for a mean of 62 months.
At 2-years follow-up, Knee Society Scores averaged 83 and the researchers found no cases of implant migration. The researchers found 17 of the 18 revisions were successful. One knee developed a subsequent case of MRSA and required debridement for a necrotic bone segment at 5 months, re-revision and another antibiotic infusion regimen. Whiteside said the patient is doing well at 42 months following surgery.
For these procedures, Whiteside recommends direct exposure as the best way to remove the cement mantle in four stages: first using osteotomes, then rongeurs and a knife, curettes and then a high-torque reamer to debride the soft tissue.
He uses cementless implants with “careful technique” rather than a spacer because the bone grows into the implants. Then he infuses antibiotics through the catheter to the knee. The fibrous cuffs on the catheter act as “a seal and prevent joint fluid from getting out and outside fluid from getting in.” He removes the catheter at 6 weeks by dissection and examines the fluid, which should be clear at this stage, Whiteside said. – by Renee Blisard Buddle
Whiteside LA. Paper #68. Presented at: Current Concepts in Joint Replacement Winter Meeting. Dec. 12-15, 2012. Orlando, Fla.
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Disclosure: Whiteside owns interest in Signal Medical Corporation and receives royalties for design and consulting from Smith & Nephew Inc.