Naidu Sanjiv H, Radin Alex
REMI Sciences, Inc., Exton, Philadelphia, PA, USA.
J Hand Surg Am. 2009 Mar;34(3):409-14. doi: 10.1016/j.jhsa.2008.11.031.
A prosthetic ulnar head that matches the mechanical properties of the sigmoid notch of the radius may produce a superior clinical outcome. In this study, we investigated the feasibility of an ultrahigh-molecular-weight polyethylene (UHMWPE) ulnar head prosthesis as a bearing material and compared the tribology (wear properties) with that of a cobalt chrome (CoCr) distal ulnar replacement.
We compared the friction properties, termed lubricity of the UHMWPE ulnar head prosthesis and polished CoCr ulnar head in an in vitro joint simulator with physiologic saline maintained at body temperature. Wear of the UHMWPE ulnar head and polished CoCr ulnar head against a synthetic bone counterface for 1 million cycles was simulated in the in vitro joint simulator. Finally, we studied the fatigue of the UHMWPE prosthesis for 3.1 million cycles of cyclic loading. Both the fatigued and nonfatigued surface were studied with thermal analysis to characterize the UHMWPE prosthesis.
The dynamic coefficient of friction for the UHMWPE prosthesis was 0.087 +/- 0.016 and was not significantly different from the polished CoCr coefficient. The synthetic counterface bone wear was 45 times less for the UHMWPE ulnar head prosthesis compared with the polished CoCr head. Both the thermal properties and the viscoelastic moduli for the fatigued UHMWPE remained unchanged compared with unloaded specimens.
Ultrahigh-molecular-weight polyethylene is a low-friction material with stable fatigue properties. In addition, in light of its low modulus of elasticity, the UHMWPE ulnar head prosthesis demonstrated low synthetic bone counterface wear compared with the polished cobalt chrome alloy prosthesis. In vitro joint simulation showed that there is a potential role for the UHMWPE ulnar head prosthesis in distal radioulnar joint prosthetic arthroplasty.
与桡骨乙状切迹力学性能相匹配的人工尺骨头可能会产生更好的临床效果。在本研究中，我们研究了超高分子量聚乙烯（UHMWPE）尺骨头假体作为一种轴承材料的可行性，并将其摩擦学特性（磨损性能）与钴铬（CoCr）尺骨远端置换物进行了比较。
我们在体外关节模拟器中，于体温下用生理盐水比较了UHMWPE尺骨头假体和抛光CoCr尺骨头的摩擦性能（称为润滑性）。在体外关节模拟器中模拟了UHMWPE尺骨头和抛光CoCr尺骨头在合成骨摩擦副上进行100万次循环的磨损情况。最后，我们研究了UHMWPE假体在310万次循环加载下的疲劳情况。对疲劳和未疲劳的表面均采用热分析来表征UHMWPE假体。
UHMWPE假体的动摩擦系数为0.087±0.016，与抛光CoCr系数无显著差异。与抛光CoCr头相比，UHMWPE尺骨头假体的合成摩擦副骨磨损减少了45倍。与未加载的标本相比，疲劳UHMWPE的热性能和粘弹性模量均保持不变。
超高分子量聚乙烯是一种低摩擦且疲劳性能稳定的材料。此外，鉴于其低弹性模量，与抛光钴铬合金假体相比，UHMWPE尺骨头假体的合成骨摩擦副磨损较低。体外关节模拟表明，UHMWPE尺骨头假体在桡尺远侧关节置换术中具有潜在作用。
