The technique of cement application has no influence on cement intrusion in total knee arthroplasty: randomized study comparing three different techniques.

PURPOSE

The aim of the study was to compare the distance of intrusion of the cement into the bone in different areas both in the femur and the tibia in vivo, measured in the radiograph after implanting a total knee arthroplasty (TKA) with three different cement techniques.

METHODS

A prospective randomized study of 90 consecutive patients operated on at our institution with a cemented U2 Knee System TKA and medium viscosity Simplex P bone cement. After pulse lavage, the cement was applied on the bone surfaces (group 1), on the implant surfaces (group 2) or both on the bone and the implant surfaces (group 3). The cement intrusion was measured in the postoperative radiographs in eight different regions in the tibial component and in six regions in the femoral component. The cement employed was calculated by weighting the cement after mixing and weighting the discarded cement.

RESULTS

The average intrusion of the cement was similar in all three groups of cementing techniques in the femoral components (1.6 mm; p = 0.386), and in the tibial components (2.6 mm; p = 0.144). The intrusion of the cement in the tibia was greater in women than in men (p = 0.04). We used 21.1 (SD 5.8) g of cement in average. The amount of cement employed was greater when the cement was applied on both (implant and bone) surfaces (group 3: 24.03 g in average) than when it was applied only on the bone (group 1: 20.13 g; p = 0.01) or only on the implants (group 2: 19.20 g; p = 0.001). The amount of cement employed was greater in men than in women (p = 0.002) and it was also greater when a PS femoral component was used (p = 0.03). The amount of cement employed was directly correlated with the height of the patients (p = 0.01) and with the bigger size of the components (p < 0.001).

CONCLUSION

All three cement application techniques have similar intrusion distance of the cement into the bone, and the intrusion depth of the cement into the trabecular tibial bone is greater than the minimum suggested for fixation.