In June 1999 a randomised double-blind study on tibial base plate fixation was started to determine whether, when using the Profix® total knee replacement, the addition of screws improved the fixation of the tibial base plate. To date 138 total knee arthroplasties (THAs) have been performed, 119 of which were available for study. Selected randomly, 56 patients had supplementary screws inserted through the base plate and 63 did not.

After a minimum of 12 months follow-up, 27 patients had some radiolucent lines at the prosthesis-bone interface on the tibial component. These lines occurred in 14 cases with supplementary screws and 13 without screws. In one patient without supplementary screws, the tibial tray had subsided into the tibia. Statistically there was no apparent difference between the two groups.

The early results of our study raise questions about the value of supplementing base plate fixation in uncemented THAs, especially considering the additional cost of the screws and their potentially detrimental consequences.