Is bone density in the distal femur affected by use of cement and by femoral component design in total knee arthroplasty?

The objective of this study was to evaluate changes in bone density in the distal femur 2 years after total knee arthroplasty with four different implant designs using cemented or cementless femoral components. Bone density was measured retrospectively from radiographs of 114 knees, using a densitometer. A decrease in bone density of up to 57% was identified in the distal femora with a cemented femoral component 2 years after surgery, compared with a decrease of up to 28% with a cementless, porous-coated component of the same design. The differences between the four implant designs in the changes in bone density in the anterior distal femur were significant at 2 years (P < 0.001). A possible cause of this result may be a difference in load transfer due to the different methods of fixation. The surgeon should expect decreased bone density in the distal femur at the time of revision surgery, especially with a cemented femoral component.