Revision Total Knee Arthroplasty

                                                                                                       - Assistance provided by Michael Berend MD.
- Surgical Approach: (Surgical Approach for Primary TKR);
    - prior to component removal, take the knee thru a range of motion and evaluate patellar tracking and evaluate knee stability in extension,
            mid-flexion, and full flexion;

- Femoral Component Removal:
    - steps in femoral component removal:
           - expose bone-component interface;
           - anterior flange:
                   - begin with a half inch straight osteotome under the anterior flange;
                   - use a half inch curved osteotome to free-up the interface on the medial and lateral aspects of the notch;
                   - use a gigli saw placed under the anterior flange and pull anteriorally against the component while sawing distally until one reaches 
                            the pegs on the femoral component;
           - posterior flange:
                  - well fixed porous femoral component can pose a serious problem if bone has solidly healed into porous coated pegs;
                  - these cannot be easily reached by osteotomes or high speed burrs;
                   - gigli saw can be placed around the posterior condyles and drawn distally to release the interface;

- Tibial Component Removal: (see primary tibial components)
    - initial exposure:
           - in TKR revision, remove the femoral component first, unless the tibia has an obstructing central eminence;
           - remove polyethylthene liner first to improve exposure;
           - beware that w/ revision TKR posterior neurovascular structures may be scarred and adherent to posterior capsule & hence may be at risk
                     for injury during bone cuts and soft tissue dissection;
           - box cut
                     - femoral component is removed first, and the femoral cuts (including the box cuts) are made;
                     - usually the PCL will be released with the box cuts, but if not, then the remainder of the PCL is removed;
           - if the metal backed component has a large stem or keel, a good exposure is essential;      
                  - hyperflex and externally rotate the knee and translate the tibia forward and see if the posterior edge of the tibial component 
                          clears the edge of the femoral condyles;
                  - if tibial component does not clear the femoral condyles, then release the posterior capsule off of the femur;
                          - maximally translate the tibial posteriorly (which makes the femur prominent) during this maneuver;    
                  - carefully place a blunt tipped double pitch fork just posterior to the proximal tibia and lever off of the distal femur in order to 
                          translate the tibial forward;
                  - if exposure is still not adequate, then elevate the medial and lateral capsule off of the proximal tibia;
           - expose interface with knife or cautery:
           - begin dividing the interface with a half inch straight osteotome;
                  - a bone-metal interface can be removed w/ high speed burrs and flexible osteotomes;
           - continue with a wider osteotome or with an oscillating saw to completely disrupt the bone metal interface;
           - use a bone tamp or an axial extractor with a slap hammer to remove the component;
           - far medial exposure for lateral interface disruption;
                  - use homan retractor to allow the osteotome a far medial path across the interface;
                  - as the osteotome is moved in a lateral direction the entire lateral and posterolateral interface is disrupted;

    - componnent extraction:
           - following the disruption of the bone-metal interface, the axial extractor w/ its attached slap hammer can be applied;
           - often it may be difficult to extricate the loose tibial component because the femoral condyles block the passage of the tibial 
                  component (and its stem) out the tibial medullary canal;
                  - in this case, the surgical exposure is inadequate and maneuvers must be made which will allow the tibia to be booked forward 
                         (which clear the posterior portion of the tibial component from underneath the femoral component);
           - if an intramedullary stem remains, this can be sectioned with an osteotome and removed in pieces;
    - carefully remove remaining cement, irrigate bony surfaces and remove fibrous tissue;
    - a bone-metal interface can be removed w/ high speed burrs and flexible osteotomes;
    - with the components removed, saw a thin layer of bone off the proximal tibia and distal femur, taking the cement w/ it;
    - all poly components can be removal w/ oscillating saw;
           - remove tibial components that are made entirely of polyethylene by sawing across interface & thru any keel or post ect;
           - w/ the components removed, saw a thin layer of bone off the proximal tibia and distal femur, taking the cement layer with it;

- Patellar Component Removal:
    - if the patellar component does not appear to be causing symptoms, and if it appears to be well fixed at surgery, consider leaving it in place;
    - begin by clearing the soft-tissue from the bone-implant interface with a knife or cautery;
    - a one-inch straight osteotome can then be used to remove the component;
    - do not lever the component off as this can cause patellar fx;
    - a metal-backed patella may require a diamond burr for removal

Femoral cement removal in revision total hip arthroplasty. A biomechanical analysis.

Management of intraoperative femur fractures associated with revision hip arthroplasty.

Isolated patellar component revision of total knee arthroplasty

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, May 10, 2012 4:15 pm