Two-stage protocol remains the gold standard of care for infection after TKA

Updated 4/5/09

Two-stage protocol remains the gold standard of care for infection after TKA

Link  http://www.orthosupersite.com/view.asp?rID=30098

Using an implant and antibiotic-cement composite may help maintain length, soft tissue compliance.

By Gina Brockenbrough
ORTHOPEDICS TODAY
August 2008

A two-stage treatment protocol and intravenous antibiotics may help surgeons effectively manage infections after total knee arthroplasty, according to a Texas surgeon.

Richard E. Jones, MD, said during his presentation at the 9th Annual Current Concepts in Joint Replacement Spring Meeting, "All in all, we can say that the two-stage technique gives us good delivery of antibiotics, helps clean up infections, maintains soft tissue length and enhances rehabilitation and joint restoration."

Prescribing nutritional supplementation and encouraging patients to quit smoking may also improve patients' capacity for wound healing.

When infection is suspected, surgeons should be aware of elevated C-reactive protein (CRP) and erythrocyte sedimentation rates.

"Remember that the CRP after surgery goes down within 3 weeks," Jones said. "The sed rate takes about 3 months before it goes down." He also highlighted the unreliability of sinus cultures and instead recommended that surgeons obtain deep tissue cultures.

Establish organism

"The key is to establish the organism and the sensitivity of the organism and then direct your parenteral and cement antibiotic combinations for specificity," Jones said. Surgeons should also categorize patients into one of the following physiologic classes of healing capacity:

• Type A for patients with a normal healing capacity;

• Type B for those with local or systemic combined wound healing deficients; and

• Type C for high-morbidity patients.

The surgical goals for treating infected cases include debriding all necrotic tissue and eliminating the dead space. Jones' protocol involves a radical debridement, implanting an antibiotic-cement composite, and a definitive reconstruction.

"The concept that we developed was incorporating an implant moving surface with a cement-antibiotic composite that maintains length, gives you soft-tissue compliance and patients can get up and walk on it," Jones said. He forms a custom implant that allows fluid at the interface for easy future removal and uses antibiotic beads which eliminate any dead space.

This radiograph shows an infected revision TKA with multiple sinus tracks.

At 7 years post reconstruction, the infection is cleared.

Jones noted that muscle flaps may be necessary to obtain closure in some cases.

Antibiotic delivery

"We use calcium sulphate pellets with antibiotic, because these actually absorb within the soft tissue and you do not have to go back and dig them out like you do cement antibiotic beads," Jones said.

For the mixture, he uses 24 cc of antibiotic powder in every 40-g pack of cement powder. "Remove 24 cc of cement powder so that you have a working time of 1.5- to 2-times normal," Jones said.

"You use a Groshong (Bard Access Systems) catheter for parenteral antibiotic delivery and we go back at 3 months on knees with a stable wound, normal CRP and sed rate," Jones said. For the second stage of the procedure, he noted that samples with a white cell count greater than 20 signify a continued infection.

Soft tissue coverage and using concomitant muscle flaps may also necessary.

"Be friendly with your plastic surgeon and ancillary support, particularly in terms of re-educating patients to be in control," Jones said.

A note from the editor:
In September, Javad Parvizi, MD, FRCS, will begin a bi-monthly column for Orthopedics Today called Infection Watch.

For more information:

• Richard E. Jones, MD, can be reached at 5920 Forest Park, Suite 600, Dallas, TX 75235; 214-902-1431.. He has an ownership interest and intellectual property rights with DePuy.

Reference:

• Jones RE. The infected knee: The two stage imperative. #64. Presented at the Annual Current Concepts in Joint Replacement Spring Meeting. May 18-21, 2008. Las Vegas.

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