Prosthesis design of animal models of periprosthetic joint infection following total knee arthroplasty: A systematic review

Background
The number of periprosthetic joint infections (PJI) after total knee arthroplasty (TKA) is increasing annually. Animal models have been used to clarify their clinical characteristics and the infection mechanism of pathogenic bacteria, However, since the prosthesis design of animal models is not uniform, it is difficult to simulate the environment of clinical PJI.
Objectives
To retrospect the progress on the prosthesis design of animal models of PJI after TKA and to summarize the criteria for evaluating a clinically representative model of PJI.
Methods
This systematic review was reported on the basis of Systematic Reviews and Meta-Analyzes (PRISMA). Pubmed, EMbase, Cochrane Library, Web of Science, Wanfang Data and China National Knowledge Infrastructure were researched for animal models of PJI after TKA from database establishment to April 2019 according to Chinese and English retrieval words, including “periprosthetic joint infections and total knee arthroplasty,” “periprosthetic joint infections and model,” “periprosthetic joint infections and biofilm,” and “total knee arthroplasty and model.”
Results
A total of 12 quantitative studies were enrolled in our study finally: 8 representative studies described prosthesis designs used in PJI animal models, 4 studies described prosthesis designs in non-infected animal models which were suitable for infection models. The major problems need to be dealed with were prosthesis, installation location, material, the function of separating the articular and medullary cavity, fixation manner, and the procedure of preserving the posterior cruciate ligament.
Conclusion
A highly representative design of the animal prosthesis of PJI should meet the following criteria: the surface of the prosthesis is smooth with the formation of biofilm, composed of titanium-6Al-4V or cobalt-chromium-molybdenum alloy; prosthesis can bear weight and is highly stable; and it can connect the joint cavity and medullary cavity simultaneously. To reach a more reliable conclusion, further experiments and improvements are required.

背景：全膝关节置换术（total knee arthroplasty, TKA）后假体周围关节感染（periprosthetic joint infections, PJI）的发病率逐年上升。研究人员已利用动物模型阐明此类感染的临床特征及病原菌的感染机制，但由于动物模型所用假体的设计并不统一，难以模拟临床假体周围关节感染的真实环境。

研究目的：梳理全膝关节置换术后假体周围关节感染动物模型的假体设计研究进展，并总结具备临床代表性的假体周围关节感染动物模型的评价标准。

研究方法：本系统评价依据《系统评价与荟萃分析报告规范》（Systematic Reviews and Meta-Analyzes, PRISMA）进行报告。检索自建库至2019年4月PubMed、EMbase、Cochrane图书馆、Web of Science、万方数据及中国知网（China National Knowledge Infrastructure, CNKI）数据库中关于全膝关节置换术后假体周围关节感染动物模型的相关研究，检索词涵盖中英文，包括“periprosthetic joint infections and total knee arthroplasty”“periprosthetic joint infections and model”“periprosthetic joint infections and biofilm”“total knee arthroplasty and model”。

研究结果：本研究最终纳入12项定量研究，其中8项代表性研究描述了假体周围关节感染动物模型所用的假体设计，4项研究描述了适用于感染模型的非感染动物模型的假体设计。当前亟待解决的核心问题涉及假体、安装位置、材料、关节腔与髓腔的分隔功能、固定方式以及后交叉韧带保留流程。

研究结论：具备高度临床代表性的假体周围关节感染动物假体设计应满足以下标准：假体表面光滑且可形成生物膜，材质为钛-6铝-4钒合金或钴-铬-钼合金；假体可承重且具备高稳定性；能够同时连通关节腔与髓腔。为获得更可靠的研究结论，仍需开展进一步实验与优化改进。