Polyetheretherketone implant surface functionalization technologies and the need for a transparent quality evaluation system

• Published in: Polymer international 2021-08, Vol.70 (8), p.1002-1015
• Main Authors: Schaffarczyk, Dietmar, Knaus, Jennifer, Peeters, Gunther, Scholl, Dieter, Schwitalla, Andreas, Koslowski, Christoph, Cölfen, Helmut
• Format: Article
• Language: English
• Subjects: bone implant; Bone implants; Ceramic coatings; Ceramics; Inflammation; Mechanical properties; Osseointegration; Polyether ether ketones; polyetheretherketone (PEEK); Polymers; Quality assessment; quality evaluation; Quality standards; Safety; safety and performance evidence level (SPEL); surface functionalization; Surgery; Surgical implants; Titanium; Transplants & implants
• ISSN: 0959-8103; 1097-0126
• DOI: 10.1002/pi.6162

For bone implants, osseointegration resulting in a good and fast bone–implant contact is of primary importance to secure a proper implant function and to avoid implant loosening or inflammation resulting in necessary revision surgeries causing pain to the patients and immense costs. In particular, polyetheretherketone (PEEK) is a promising implant material due to the close mechanical properties to bone, but it is entirely bio‐inert, hindering osseointegration and making surface functionalization necessary. Many different surface functionalization technologies have been reported of both physical and chemical nature. The same is true for the other prominent implant materials titanium and ceramics. Although they already have inherently better osseointegration than PEEK, they are much harder and stiffer than bone and brittle in the case of ceramics. Surface functionalization, which can be subdivided into surface coating and material modification, needs to be judged from a quality and safety viewpoint. However, a literature research resulted in the realization that no quality standard yet exists for implant surface functionalizations. This makes it difficult to near impossible to compare the safety and performance of different surface‐functionalized bone implants, clearly showing the need to establish a transparent quality evaluation system for bone implants. This perspective article gives the state of the art and then develops a quality evaluation system based on six main categories as important benchmarks for the quality of surface‐functionalized bone implant materials. A simple catalog of questions can be answered, and from the resulting scores the Safety and Performance Evidence Level (SPEL) representing the safety and quality of a given implant can be calculated as a percentage. This simple SPEL system allows an easy and transparent judgment and comparison of bone implants, ensuring the easy identification of safe and well‐performing high‐quality bone implants in the future. © 2020 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This article shows the results of a literature analysis revealing a lack of a comparable quality evaluation system regarding surface‐functionalized bone implant materials and introduces a new quality evaluation system.