Use of bone compaction in total knee arthroplasty.

This study compared the effects of bone preparation on tibial stem stability in total knee arthroplasty. Six pairs of fresh-frozen tibias underwent implantation of an 18 x 75-mm press-fit stem (minus the tibial tray). The standard press-fit technique was performed creating a cavity 17 mm in diameter. For the bone compaction technique, stainless-steel dilators were machined ranging in diameter from 6 to 16 mm in 2-mm increments. The technique consisted of using the dilators and a mallet to create a compacted tunnel in a sequential manner to 16 mm in diameter followed by implantation of the stem. The specimens were mounted on a materials testing machine and loads were applied in both planes: anteroposterior and mediolateral. A preconditioning load of 100 N was applied followed by a second 100-N load from which the stiffness (N/mm) of implantation was calculated. The stability of the tibial stems implanted by compaction averaged 84.7% greater when compared with the press-fit stems (P < .017 by multivariate analysis).