Failure mechanisms and influencing factors on orthopaedic knee implant failure – A comprehensive review

Abstract

Background Total knee replacement (TKR) is an effective orthopaedic surgical procedure to confront osteoarthritis and restore bone joint mobility, relieve pain, and enhance the quality of life. The improvements in implant design and the use of high-wear resistance polyethylene bearings improve the survival of implants. Despite the advancements, the implants still failed and required revision surgery. Also, with an increase in the trend of young patients getting knee replacements, there is a possibility of a higher revision rate. Thus, understanding the failure cause, failure mechanisms and the influencing factors is pertinent. Methods A systematic review of the available literature was performed for different modes of failure. All the observations are collated and found the more predominant failure modes. Also, the data pertaining to the failure mechanisms, and the influencing factors of the failure mechanisms are collected from various literature and provided comprehensively. Results Infection (30%) becomes the primary cause of implant failure followed by loosening (20%) and instability (18%). The types of wear on knee implants are polyethylene wear, backside wear, impingement wear, and corrosive wear. The factors influencing these wear are material processing, shelf age, implant design, surface topography, and activity level. Conclusions Moderately cross-linked, and sequentially processed polyethylene has better wear resistance. Less conformal contact with minimum shelf age provides less wear at articulation and backside. A polished tibial tray with a sophisticated locking mechanism reduces the backside wear of PE, and proper design consideration could reduce impingement wear.