Department of Orthopedic Surgery, Rush University Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA.
J Bone Joint Surg Am. 2012 Oct 17;94(20):1877-85. doi: 10.2106/JBJS.J.01507.
Primary cementless acetabular reconstruction has shown durable long-term fixation. Late failures secondary to aseptic loosening are rare but may occur in patients with previously well-fixed components. In the present study, the histopathological characteristics of postmortem specimens were correlated with wear damage and radiographic data in an attempt to better understand the long-term events in the periacetabular tissue around well-functioning devices.
Seventeen primary cementless Harris-Galante I acetabular components with adjacent tissues were harvested after a mean of eleven years (range, four to twenty-five years) from patients whose implants were well functioning at the time of death. Undecalcified and paraffin sections were used to quantify the extent of bone and soft tissues within the porous coating and at the interface between the coating and the surrounding bone. Wear particles were identified with use of polarized light microscopy and energy-dispersive x-ray analysis. Bearing-surface volumetric wear and backside wear damage of the polyethylene liner were assessed.
All of the components were fixed by bone ingrowth (mean extent, 33% ± 21%). Particle-induced granulomas were present in the porous coating and along the interface and progressed through screw holes, ballooning into the retroacetabular bone in the longer-term specimens. Particles of femoral and acetabular origin were identified in the granulomas. Bearing-surface volumetric wear (mean, 41.6 mm3/year) increased with duration and correlated with increasing extent of granuloma in the porous coating and the increasing size of pelvic granulomas. Radiolucencies on radiographs correlated with the extent of bone and fibrous tissue ingrowth. Of the six pelvic granulomas that were identified histologically, only one was apparent on routine radiographs.
Acetabular fixation by bone ingrowth can be successful into the third decade after implantation. Osteolysis and secondary replacement of bone with particle-induced granuloma are commonly seen in the presence of excellent clinical function. Strategies designed to minimize bearing-surface wear and backside damage are important to maintain long-term bone ingrowth fixation.
原发性非骨水泥髋臼重建具有长期固定的耐用性。由于无菌性松动导致的晚期失败很少见，但可能发生在先前固定良好的部件的患者中。在本研究中，尝试通过磨损损伤和放射学数据来分析死后标本的组织病理学特征，以更好地了解功能良好的装置周围的髋臼组织的长期事件。
从患者死亡时植入物功能良好的 17 例原发性非骨水泥 Harris-Galante I 髋臼组件及其相邻组织中采集样本，平均随访时间为 11 年（4 至 25 年）。使用未脱钙和石蜡切片来量化多孔涂层内和涂层与周围骨之间界面处的骨和软组织的程度。使用偏光显微镜和能量色散 X 射线分析来识别磨屑颗粒。评估了髋臼杯的聚乙烯衬垫的表面容积磨损和背面磨损损伤。
所有的髋臼杯均通过骨长入固定（平均范围为 33%±21%）。在多孔涂层中以及在界面上，都存在颗粒诱导的肉芽肿，并通过螺钉孔向髋臼后骨扩张，在长期样本中呈气球状。在肉芽肿中鉴定出股骨和髋臼来源的颗粒。表面容积磨损（平均每年 41.6mm³）随时间延长而增加，并与多孔涂层中肉芽肿的程度以及骨盆肉芽肿的大小增加相关。放射学上的透亮区与骨和纤维组织长入的程度相关。在组织学上识别出的 6 个骨盆肉芽肿中，只有 1 个在常规放射片中可见。
植入后 3 个十年内，骨长入固定的髋臼杯可以成功固定。在临床功能良好的情况下，通常会出现骨溶解和由颗粒诱导的肉芽肿引起的继发性骨替代。为了保持长期的骨长入固定，重要的是要设计策略来最小化关节面磨损和背面损伤。
