Infection: Two-Stage Methods

Infection: Two-Stage Methods

Timothy S. Brown

Kevin I. Perry

Key Concepts

  • Successful treatment of knee chronic periprosthetic infection begins with complete removal of implants, cement, and foreign material and includes an extensive debridement.

  • Identification of the causative organism is critical to the success of the treatment.

  • The antibiotic spacer type is chosen to fit the needs of the individual patient.

  • The decision to proceed with reimplantation is carefully considered and comes after a complete treatment course with intravenous antibiotics followed by an antibiotic holiday.

  • At the time of reimplantation the absence of acute inflammation is confirmed, the joint is thoroughly debrided, and a well-balanced knee with rigid implant fixation is obtained with a combination of cementless metaphyseal cones or sleeves and cemented or cementless stems.

Sterile Instruments and Implants

  • Rigid and flexible osteotomes

  • Cement osteotomes

  • Small sagittal saw

  • Large Steinmann pins (for static spacer)

  • Cement gun (for static spacer dowel construction)

  • Luque wires (for static spacer)

  • Large external fixation set

Preoperative Planning

  • Important keys for successful removal of implants in total knee arthroplasty (TKA):

    • Adequate surgical exposure:

      • How many operations have been performed on this joint? Have there been prior soft tissue complications? Is there a sinus tract that must be excised (Figure 69.1)?

      • What is the preoperative range of motion? Will a quadriceps snip be likely?

      • Will a more extensile exposure such as tibial tubercle osteotomy be necessary to remove components or cement (Figure 69.2A and B)?

    • Obtain implant records from prior operations if at all possible.

    • Specific implant extraction tools are sometimes available for removal of components.

    • Some constructs should involve more planning:

      • Broken modular components (Figure 69.3A and B).

      • Components with offset stems

      • Components next to other hardware (plates, screws, staples)

      • Prior extensor mechanism reconstruction

        Figure 69.1 ▪ Photograph of the knee demonstrating an anterior sinus tract.

  • Radiography

    • Long leg

      • Important for understanding overall limb alignment.

    • Knee

      • Anteroposterior (AP), lateral, merchant, posteroanterior flexion. Used to assess implant interfaces, areas of bone loss, osteolysis. Also helpful in planning for the type of spacer and for the areas that will need augmentation during the spacer construction (Figure 69.4).

  • Know the previous operations

    • Get operative reports

      • Surgical approach.

      • Any complications?

        Figure 69.2 ▪ A and B, Cemented, offset stem with multiple prosthetic modular junctions within the cement mantle.

        Figure 69.3 ▪ A and B, Broken modular junction in an infected distal femoral replacing total knee arthroplasty.

  • Plan for the type of antibiotic spacer

    • No spacer (resection alone)

      • Used rarely

      • Predominately for patients who are very sick, who ar immunocompromised, with poor soft tissue envelope, or who have already failed treatment with antibiotic spacers.

    • Static spacer

      • Extensive bone loss (Anderson Orthopedic Research Institute [AORI] types 2B, 3) (Figure 69.5A-D).

      • Lack of collateral ligament integrity

      • Lack of extensor mechanism

      • Need for soft tissue reconstruction procedure (flap or graft)

        Figure 69.4 ▪ A and B, Infected, loose total knee arthroplasty with extensive bone loss on the medial tibial plateau.

        Figure 69.5 ▪ A,B. AP and lateral radiographs of an infected periprosthetic femur fracture and the static spacer used at the time of resection.

    • Articulating spacer

      • Minimal bone loss (AORI 1, 2A)

      • Intact collateral ligaments

      • Intact extensor mechanism

      • Good soft tissue envelope

      • Reliable patient

Bone, Implant, and Soft Tissue Techniques

Dec 14, 2019 | Posted by in ORTHOPEDIC | Comments Off on Infection: Two-Stage Methods

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