THE RELATION BETWEEN TRABECULAR BONE STRENGTH AND BONE-MINERAL DENSITY ASSESSED BY DUAL-PHOTON AND DUAL-ENERGY X-RAY ABSORPTIOMETRY IN THE PROXIMAL TIBIA

The feasibility of two noninvasive methods [dual photon absorptiometry (DPA) and dual energy X-ray absorptiometry (DXA)] for prediction in v ivo of local variations of trabecular bone strength within the proxima l tibia was evaluated in 14 cadaveric knees. Trabecular bone strength was measured using an osteopenetrometer and from destructive compressi on tests performed on bone cylinders, thus measuring the penetration s trength and ultimate strength in the medial, lateral, and central part of the tibial bone specimens. Linear regression analysis showed signi ficant relations between BMD measured by DPA (r(2) = 72%) or DXA (r(2) = 73%) and ultimate strength. Even closer relations between BMD (DPA: r(2) = 80%, DXA r(2) = 81%) and penetration strength of trabecular bo ne were found. We conclude that DPA and DXA are suitable methods for e valuation in vivo of local variations in trabecular bone strength with in the proximal tibia, and could easily be performed preoperatively be fore insertion of total knee arthroplasty.