Conditt Michael A, Stein Jason A, Noble Philip C
Institute of Orthopedic Research and Education, 6550 Fannin Street, Suite 2512, Houston, TX 77030, USA.
J Bone Joint Surg Am. 2004 Feb;86(2):305-11. doi: 10.2106/00004623-200402000-00013.
The use of modular tibial components in total knee arthroplasty introduces a possible source of polyethylene wear at the nonarticulating (backside) surface. However, it is not known whether this phenomenon is an incidental finding observed in unique specimens or is a feature common to all modular components. The purpose of this study was to determine the type and severity of backside wear in retrieved tibial inserts of several common total knee designs.
One hundred and twenty-four polyethylene tibial inserts of twelve different designs were retrieved at revision total knee replacements after implantation periods ranging from zero to 180 months. Each insert was visually inspected with use of a stereomicroscope for seven different modes of surface damage in four quadrants defining the backside surface.
Pitting, burnishing, and measurable polyethylene protrusions were observed on the backside of polyethylene inserts of implant designs with a variety of different capture mechanisms. Across all implant designs, pitting was observed in 90% of the retrieved specimens; burnishing, in 77%; and protrusion, in 61%. Overall, implants of the IB-II (Insall-Burstein-II) design (Zimmer) exhibited the most severe burnishing, whereas those of the Duracon design (Howmedica) had the most severe pitting. Severe protrusions were noted with inserts of one design (AMK [Anatomic Modular Knee]; DePuy). A longer time in situ was associated with larger polyethylene protrusions, but the severity of pitting and burnishing did not increase with increasing duration of implantation.
Moderate-to-severe wear of the nonarticulating surface of the tibial insert was frequently observed in all designs of knee prostheses, independent of the capture mechanism. These results indicate that new designs of modular tibial components are needed to prevent the generation of polyethylene wear debris through backside wear of total knee replacements.
在全膝关节置换术中使用模块化胫骨组件会在非关节（背面）表面产生聚乙烯磨损的潜在来源。然而，尚不清楚这种现象是在个别标本中观察到的偶然发现，还是所有模块化组件共有的特征。本研究的目的是确定几种常见全膝关节设计的翻修胫骨假体衬垫背面磨损的类型和严重程度。
在植入0至180个月后进行翻修全膝关节置换时，回收了12种不同设计的124个聚乙烯胫骨假体衬垫。使用体视显微镜对每个衬垫的背面四个象限的七种不同表面损伤模式进行目视检查。
在具有各种不同固定机制的植入设计的聚乙烯衬垫背面观察到点蚀、抛光和可测量的聚乙烯凸起。在所有植入设计中，90%的回收标本观察到点蚀；77%观察到抛光；61%观察到凸起。总体而言，IB-II（英萨尔-伯斯坦-II型）设计（捷迈公司）的植入物表现出最严重的抛光，而杜拉康设计（豪美医疗器械公司）的植入物点蚀最严重。一种设计（AMK [解剖型模块化膝关节]；迪普伊公司）的衬垫出现了严重的凸起。在位时间较长与较大的聚乙烯凸起有关，但点蚀和抛光的严重程度并未随植入时间的增加而增加。
在所有膝关节假体设计中，均经常观察到胫骨假体衬垫非关节表面的中度至重度磨损，与固定机制无关。这些结果表明，需要新型模块化胫骨组件设计，以防止全膝关节置换术背面磨损产生聚乙烯磨损颗粒。
