CHANGES IN BONE-MINERAL DENSITY OF THE PROXIMAL TIBIA AFTER UNCEMENTED TOTAL KNEE ARTHROPLASTY - A 3-YEAR FOLLOW-UP OF 25 KNEES

We measured bone remodeling of the proximal tibia prospectively for 3 years after uncemented total knee arthroplasty (TKA) in 25 knees with primary arthrosis. In the trabecular bone below the tibial component, bone mineral density (BMD) was measured in 6 different regions of inte rest (ROI), using dual photon absorptiometry (DPA). In the tibial cond yles, where the change in knee alignment indicated that the load was r educed postoperatively, a fast bone loss of 7-20% was seen during the first 6 months after surgery. A small, but significant increase in BMD of 2-7% was seen in the tibial condyles, where the load was increased . On average, the density for all ROI below the tibial component showe d a significant and progressive decrease in BMD, reaching 22% at 3 yea rs follow-up.