Stiffness of bone underlying the tibial plateaus of osteoarthritic and normal knees.

The mechanical properties of normal cancellous bone in the proximal tibia have been reported extensively in previous studies in terms of support of a total knee arthroplasty (TKA); yet, little is known about these mechanical properties in the osteoarthritic (OA) state. Fifteen normal and 28 OA tibial plateaus, obtained from autopsy or TKA, were mechanically tested using an indentor technique to assess the variation of stiffness patterns. The medial:lateral stiffness ratio calculated for the normal plateaus was significantly different from the ratios computed for specimens with medial compartment OA and lateral compartment OA; however, the ratio was unchanged in tricompartment OA. These data should receive greater consideration in the design of TKA, which has traditionally been designed on the mechanical properties of normal tibiae.