• Alexander M Kress, Rainer Schmidt, Tobias E Nowak, Melanie Nowak, Lothar Haeberle, Raimund Forst, and Lutz A Mueller.
• Department of Orthopaedic Surgery, Friedrich-Alexander-University of Erlangen-Nuremberg, Rathsberger Str. 57, 91054, Erlangen, Germany.
• Arch Orthop Trauma Surg. 2012 Aug 1;132(8):1111-9.

PurposeBone loss around uncemented femoral components is suspected to precede implant loosening and contribute to problems in revision surgery. Short-stemmed cementless femoral components are designed to preserve proximal femoral bone stock and ultimately the longevity of the prosthesis.MethodsWith quantitative computed tomography-assisted osteodensitometry, we prospectively analyzed femoral cortical and cancellous bone density (BD) and contact area changes of an uncemented collum femoris preserving stem (n = 38) 10 days, 1, 3 and 7 years post-operatively.ResultsSeven years post-operatively, cancellous BD (mg CaHA/mL) had decreased by as much as -66 % and cortical BD by up to -27 % at the metaphyseal portion of the femur; the decrease was progressive between the 1- and 3-year examinations and halted thereafter. Contact area (in % out of a possible 100 %) decreased proximally between the 1- and 3-year follow-up.ConclusionProximal cortical and cancellous bone density loss and decrease of contact area indicate that metaphyseal fixation cannot be achieved. The lack of cortical BD loss and increase of contact area values below the trochanter minor suggest diaphyseal fixation.

24 keywords...

hide…