Status of surface modification techniques for artificial hip implants

Abstract

Surface modification techniques have been developed significantly in the last couple of decades for enhanced tribological performance of artificial hip implants. Surface modification techniques improve biological, chemical and mechanical properties of implant surfaces. Some of the most effective techniques, namely surface texturing, surface coating, and surface grafting, are applied to reduce the friction and wear of artificial implants. This article reviews the status of the developments of surface modification techniques and their effects on commonly used artificial joint implants. This study focused only on artificial hip joint prostheses research of the last 10 years. A total of 27 articles were critically reviewed and categorized according to surface modification technique. The literature reveals that modified surfaces exhibit reduced friction and enhanced wear resistance of the contact surfaces. However, the wear rates are still noticeable in case of surface texturing and surface coating. The associated vortex flow aids to release entrapped wear debris and thus increase the wear particles generation in case of textured surfaces. The earlier delamination of coating materials due to poor adhesion and graphitization transformation has limited the use of coating techniques. Moreover, the produced wear debris has adverse effects on biological fluid. Conversely, the surface grafting technique provides phospholipid like layer that exhibited lower friction and almost zero wear rates even after a longer period of friction and wear test. The findings suggest that further investigations are required to identify the role of surface grafting on film formation and heat resistance ability under physiological hip joint conditions for improved performance and longevity of hip implants.

An Overview on the Tribological Performance of Titanium Alloys with Surface Modifications for Biomedical Applications

“…There is an increasing trend of using surface modifications in the manufacturing process of implants. However, more advancement is still needed in this specific field to minimize the wear rate of biomedical implants [40]. The surface modification methods can be mainly divided into three main categories, which are described below.…”

“…Surface coatings are applied to provide a layer onto the material surface with the purpose of improving the surface properties, and reducing the friction and wear rates [40]. Surface coatings can prevent the production of wear particles and improve the lifetime of medical implants [40]. There are various coating methods as wear resistant coatings such as metal nitriding, plasma nitriding, laser gas alloying, laser treatments, laser cladding, and sputtering.…”

Selective laser melted titanium implants play a positive role in early osseointegration in type 2 diabetes mellitus rats

“…Dental implants also require proper mechanical properties. Among titanium alloys, the Ti-6Al-4V alloy has been demonstrated to have a relatively low Young's modulus, and this characteristic helps to avoid the stress shielding effect after implantation 28) . The SLM implants in our study using Ti-6Al-4V alloy as a raw material with a feedback low elastic modulus, which was verified by the yield strength results.…”

Path Planning for Laser Cladding Robot on Artificial Joint Surface Based on Topology Reconstruction

“…In order to meet the special requirements of artificial joint application, titanium alloys are usually selected as the substrate, and one or more layers of high performance coating is fabricated on the surface of titanium alloys. In recent years, laser cladding as a novel and advanced surface modification technology has been gradually used to prepare ceramic coatings on the surface of titanium alloys to improve the wear resistance or impart bioactive properties [7,8].…”