Markolf K L, Amstutz H C, Hirschowitz D L
J Bone Joint Surg Am. 1980 Dec;62(8):1315-23.
Extra-long-neck, large-stem Trapezoidal-28 femoral components with standard and modified large flanges were cemented into fresh cadaver femora and measurements were made of the movement of the prostheses relative to the bone as load was applied to the head of the prosthesis. In the presence of collar-calcar femoral contact, the prosthesis subsided very little under load; displacements for a load of 2000 newtons were less than 0.1 millimeter. Removal of bone and acrylic support beneath the undersurface of the flange by sawing a thin gap caused no increase in the displacement of the stem tip in most specimens, but the displacements of the collar relative to bone for the standard flange design increased by an average of 0.014 millimeter (8 to 28 per cent) under a 2000-newton force when contact was removed, while the displacements for the prostheses with a modified large flange that extended to the cortical rim of the resected neck increased 0.047 to 0.060 millimeter (56 to 432 per cent), indicating greater support from the collar due to the increased area of contact. An increase of the stem-flange angle of 22 degrees (from 30 to 52 degrees), making the flange more horizontal, had no significant effect on the results for large-flanged units. Prostheses with a standard flange and a one to two-millimeter Silastic liner between cement and bone subsided as much as twenty times more than rigidly cemented units. In the presence of the liner, removal of collar-calcar contact increased the collar displacement by 29 to 75 per cent, indicating a possibly important function of the flange for components cemented in soft bone or components that may become loose or be surrounded by a fibrous membrane. Repacking of the gap between the collar and bone with acrylic after removal of part of the calcar femoral reduced subsidence in one specimen, while the acrylic in a second specimen cracked out during reloading. Based on our laboratory experience with sixteen specimens, we believe that it would be extremely difficult to achieve an effective degree of uniform calcar femorale-collar contact at operation and that one or two localized contact areas would be the more common situation after total hip replacement.
将带有标准和改良大凸缘的超长颈、大柄梯形-28股骨假体用骨水泥固定在新鲜尸体股骨中，并在假体头部加载时测量假体相对于骨骼的移动情况。在存在颈-小粗隆股骨接触的情况下，假体在加载时下沉很少；2000牛顿载荷下的位移小于0.1毫米。通过锯出一条窄缝去除凸缘下表面下方的骨和丙烯酸支撑，在大多数标本中，柄尖的位移没有增加，但对于标准凸缘设计，在去除接触后，在2000牛顿力作用下，颈相对于骨骼的位移平均增加了0.014毫米（8%至28%），而对于改良大凸缘延伸至切除颈部皮质边缘的假体，位移增加了0.047至0.060毫米（56%至432%），表明由于接触面积增加，颈的支撑作用更大。柄-凸缘角度增加22度（从30度增加到52度），使凸缘更水平，对大凸缘假体的结果没有显著影响。带有标准凸缘且在骨水泥与骨之间有1至2毫米硅橡胶衬垫的假体下沉量比刚性骨水泥固定的假体多20倍。在有衬垫的情况下，去除颈-小粗隆接触会使颈位移增加29%至75%，这表明对于骨水泥固定在松质骨中的假体或可能松动或被纤维膜包围的假体，凸缘可能具有重要作用。在去除部分小粗隆股骨后，用丙烯酸重新填充颈与骨之间的间隙，在一个标本中减少了下沉，而在第二个标本中，丙烯酸在重新加载时裂开。基于我们对16个标本的实验室经验，我们认为在手术中要达到有效的股骨距-颈均匀接触程度极其困难，全髋关节置换术后更常见的情况是有一两个局部接触区域。
