以骨泥或無骨泥方式施行人工髖關節置換手術後，股骨近端硬質骨均將發生骨質重塑改變。應力遮蔽效應是在諸多造成骨質重溯現象中最重要因素之一，其主要原因來自股骨柄於植入股骨後所產生的應力分佈重大改變。為深入了解目前臨床上常使用之對稱型及解剖型股骨柄於植入股骨後所產生骨質流失差異性，本研究乃設計以體外力學實驗，針對無骨泥固定情況下，以對稱型及解剖型股骨柄施行人工髖關節置換手術後，比較術後二者間應力遮蔽效應的差異性。實驗的方法，是利用單軸向應變規及人造股骨進行股骨近端硬質骨之表面應變量測。以八件人造股骨依股骨柄之外型區分為對稱型(C-Fit)及解剖型(PCA)兩組（每組四件），在1,000N的壓力負荷下，分別比較上述二種不同幾何形狀之股骨柄在無骨泥植入情況下，二者間股骨近端硬質骨應變值的差異性。實驗結果顯示，在無骨泥植入情況下，植入解剖型股骨柄之股骨近端應力遮蔽效應較對稱型股骨柄顯著。本研究結果有效證實以無骨泥方式施行解剖型股骨柄置換手術後，將產生較明顯之應力遮蔽效應。

Adaptive bone remodelings in the proximal femur often occur following either cemented or uncemented total hip arthroplasty (THA). Stress shielding is one of the most significant determinants of this bone remodeling, and it results from changes in force distribution following prosthetic implantation. In order to evaluate the alteration of stress distribution after implantation of straight or curved femoral stem, this study was designed to compare the difference of stress shielding for straight and curved stems in cementless THA using in vitro experimental method. Uniaxial strain gauges and synthetic femora were used to perform the surface strain measurement of proximal femora. A total of eight synthetic femora were enrolled and assigned into C-Fit (Straight stem) and PCA (Curved stem) groups (four in each). Under 1,000-N axial loading, the surface strains of proximal femora were measured and compared between C-Fit and PCA implanted femora with press-fit fixation. The results revealed that the straight stem group got less stress shielding as compared to that of the curved stem group. We concluded that curved stem caused a more significant stress shielding as compared to those with straight stem.