Mechanical stability of cementless tibial components in normal and osteoporotic bone.

There is renewed interest in cementless total knee arthroplasty, yet the optimal tibial design remains elusive. The purpose of this study is to evaluate the stability of various tibial component designs in normal and osteoporotic bone. Two cementless tibial implants, a CoCr beaded keeled baseplate and a two-pegged, highly porous titanium design underwent mechanical testing in normal and osteoporotic bone models. Decreased stability was observed in both designs in the osteoporotic model compared with "normal" bone (p < 0.0017). Stability of the keeled design was greater than the two-peg design in both densities; however, this difference was statistically significant only in the "normal" bone model (p = 0.005). This study demonstrates that cementless tibial component stability is affected by both implant design and host bone quality.