Perona P G, Lawrence J, Paprosky W G, Patwardhan A G, Sartori M
Department of Orthopaedics and Rehabilitation, Loyola University Medical Center, Maywood, Illinois 60153.
J Arthroplasty. 1992 Dec;7(4):537-47. doi: 10.1016/s0883-5403(06)80076-8.
Micromotion has been shown to affect bony ingrowth into cementless components. This study was designed both to quantitate initial micromotion at the prosthesis-periacetabular bony interface and to compare different methods of commonly employed acetabular component fixations, ie, a press-fit hemispherical titanium cup, a press-fit hemispherical titanium cup with one and two dome screws, a press-fit titanium hemispherical cup with three spikes, and a cemented chromium-cobalt cup. The press-fit component without screws demonstrated the greatest motion equaling 162 microns at the ilium, 97 microns at the publis, and 54 microns at the ischium. With one and two screws placed into the dome, the mean ileal displacement decreased by 28 microns (17%) and 36 microns (22%), respectively. Dome screw placement demonstrated a minimal effect at the pubis and ischium. Compared to the press-fit component without augmentation, the tri-spike motion was less at the pubis and ischium. The cemented prosthesis provided the least amount of motion in all three areas tested. This experiment demonstrates that the ilium provides the least amount of support to immediate acetabular fixation, while the pubis (anterior column) and ischium (posterior column) provide more stability. One dome screw does not affect the stability of a hemispherical prosthetic cup significantly. A two dome screw fixation provides an added method of support at the ilium, but fails to decrease motion at the pubis or ischium significantly. The tri-spike fixation does not restrict motion at the ilium to the extent as the dome screws, but its effect at the ischium and pubis is much more pronounced. The obvious difference between initial motion seen with cemented versus uncemented components may suggest that before surgery, patients may need a period of protected weight bearing until ingrowth has occurred.
微动已被证明会影响骨长入非骨水泥型假体组件。本研究旨在定量分析假体 - 髋臼周围骨界面处的初始微动，并比较常用的髋臼组件固定方法，即压配式半球形钛杯、带一枚和两枚穹顶螺钉的压配式半球形钛杯、带三个尖钉的压配式钛半球形杯以及骨水泥型铬钴杯。不带螺钉的压配组件显示出最大的微动，在髂骨处为162微米，在耻骨处为97微米，在坐骨处为54微米。在穹顶处植入一枚和两枚螺钉后，髂骨的平均位移分别减少了28微米（17%）和36微米（22%）。穹顶螺钉植入在耻骨和坐骨处的影响最小。与未增强的压配组件相比，三尖钉在耻骨和坐骨处的微动较小。骨水泥型假体在所有三个测试区域提供的微动最少。该实验表明髂骨对髋臼即时固定的支撑最少，而耻骨（前柱）和坐骨（后柱）提供了更多稳定性。一枚穹顶螺钉对半球形假体杯的稳定性影响不大。两枚穹顶螺钉固定在髂骨处提供了额外的支撑方法，但在耻骨或坐骨处未能显著减少微动。三尖钉固定在髂骨处对微动的限制程度不如穹顶螺钉，但在坐骨和耻骨处的效果更为明显。骨水泥型与非骨水泥型组件初始微动的明显差异可能表明，术前患者可能需要一段时间的保护性负重，直到骨长入发生。
