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    SURGICAL PEARLS: Tips and Techniques for Revision TKA from Dr. Mark Pagnano

    With triple-digit increases in revision total knee arthroplasty (TKA) projected for the next decade or so, [1] orthopaedic surgeons need to be ready for the influx of patients needing more complex care.

    To help with that process, Mark W. Pagnano, MD, from Mayo Clinic, Rochester, Minnesota, shared his tips and techniques for revision TKA at ICJR’s Winter Hip & Knee Course in Vail, Colorado.

    Exposure

    The importance of good exposure in the primary TKA setting is magnified in the revision setting. When performing a revision TKA, the surgeon is dealing with an arthroplasty that has already failed, “so this is not the time to be cute,” Dr. Pagnano said.

    He will initially extend the previous incision by about 1 inch at either end so he can get into native tissue to better identify the soft tissue planes. This helps to safely raise the soft tissue flaps.

    In patients with multiple prior incisions, Dr. Pagnano recommends using the most lateral of the anteriorly based incisions.

    Thin and Narrow Flexible Blade

    Dr. Pagnano believes that the best tool for freeing the cement-bone interface under the tibial tray is a thin and narrow flexible saw blade. The narrower width and smaller excursion of a narrow blade allows the surgeon to more safely work in the posterior aspect of the knee, undercutting the posterior part of the tibial tray.

    This narrow blade even allows the surgeon to cut from a 90° angle, cutting across the posterior aspect of the tibial tray. It is important to break as much of the cement-bone interface as possible during this step to facilitate the next step: disimpaction of the tibial tray.

    Tibial Tray Removal

    Dr. Pagnano’s favorite tip is using a narrow, square-tipped impactor under the lateral side to disimpact the tibial tray.

    Some surgeons, Dr. Pagnano said, try to dis-impact from the medial side. The problem is that most of the cement that’s still adherent to the tibial tray is posterior and lateral due to the difficulty in safely inserting a saw blade into that area. Disimpaction of the tibial tray from the medial side only could result in the posterolateral tibia being crushed or a large piece of posterolateral bone being broken off.

    Instead, Dr. Pagnano begins by creating a small “nick” in the bone lateral to the tibial tubercle using a needle-nose rongeur. He then cuts a small slit in the retinaculum just lateral to the patellar tendon. The narrow, square-tipped impactor is fed up underneath the patellar tendon and seated under the lateral edge of the tibial tray, allowing easy disimpaction from the lateral side.

    Metaphyseal Sleeves and Cones

    When used in combination with press-fit stems, metaphyseal sleeves and cones tend to hit the hard bone on the medial side of the tibia and slide laterally, putting the tibial tray in a valgus position.

    For that reason, Dr. Pagnano deliberately pulls the reamer into a tiny bit of varus when he starts preparation of the tibia. As he increases the size of the reamers and reaches the correct size distally, he avoids the tendency of the tibial tray to fall into valgus.

    Click the image above to watch Dr. Pagnano’s presentation.

    Disclosures

    Dr. Pagnano has disclosed that he has product development agreements with DePuy Synthes and Stryker.

    Reference

    1. New study projects the future volume of primary and revision TJAs in the US. Published March 6, 2018, on ICJR.net. Accessed April 16, 2018.