- Component Insertion:
- tibial insertion:
- cement is applied to the proximal tibial surface, and the surgeon uses gloved fingers to manually press cement into proximal tibial surface;
- subsequently additional cement is applied to the proximal tibial surface;
- tibial tray and its stem are precoated w/ cement and then are inserted;
- note that the lateral femoral condyle may block straight access for insertion of the tibial component, which may cause the
tibial component to internally rotate as it is inserted;
- this is prevented by levering a curved Homan retractor against the back of the tibial plateau, which allows the tibia to be subluxed anteriorly;
- after impaction, & excess cement removal;
- femoral insertion:
-
femoral component is then impacted into position and again, excess cement removed.
- take care to avoid femoral component flexion during the insertion (impact the femur in a slightly anterior direction);
- trial component: trial spacer is placed;
- knee is then placed in full extension to further compress components while the cement hardens;
- patella is then cemented into position, using a patellar clamp to hold all-poly patellar component.
- Final Testing of Stability and Tracking:
- re-insert the trial polyethylene component and be sure that the patient is able to achieve full extension;
- it is certainly possible for both the femoral and tibial surfaces to rest on more than 1 mm of cement each, which could result in incomplete flexion;
- if this is the case use a smaller polyethylene component;
- if lateral patellar subluxation is present, perform a
lateral retinacular release;
- references:
Influence of collateral ligament laxity on patient satisfaction after total knee arthroplasty: a comparative bilateral study
- Cement Removal:
- after cement has hardened, excess cement is again removed w/ small osteotome and pickup;
- note that vigorous chipping of the excess cement can cause it to fly out and rebound off unsterile surfaces (such as OR lights or the surgeon's face);
- replace the curved knee retractors and the Mchale retractor along the sides of the tibia to maximize exposure;
- remove any cement along the posterior surface of the tibia;
- clean the tibial tray of debris and soft tissue;
- Polyethylene Insertion:
- curved knee retractors should be in place and the tibial subluxed forward;
- insert the definative polyethylene component, taking care that no soft tissue is entrapped by the polyethylene;
- this could cause incomplete seating of the component as well as pain from traction on the soft tissue;
Cement penetration with pulsed lavage versus syringe irrigation in total knee arthroplasty.
