The effect of stem modularity and mode of fixation on tibial component stability in revision total knee arthroplasty

The effect of stem length, diameter, and mode of fixation on the -motion an d stress transfer of a cemented tibial tray were evaluated for in 12 cadave r knees. There was a significant decrease in motion of the tibial tray with increasing press-fit stem length (75-150 mm) and increasing stem diameter (10-14 mm). Cemented tibial stems showed significantly less tray motion tha n uncemented stems. The short cemented stems produced tray stability equiva lent to long press-fit stems. Although there was a trend for increased prox imal tibial stress shielding with the use of cement and longer, wider stems , the trend was not statistically significant. Modular, press-fit stems can achieve tray stability similar to a smaller cemented stem and can avoid th e potential problems with cement.