Wilson CJ, et al. - Researchers analyzed current evidence pertaining to knee instability after total knee arthroplasty (TKA), with an intent to identify time to failure between primary and revision TKA. Also, they considered the patient, surgical and implant features of primary TKA patients revised for knee instability, and investigated methods used for knee instability diagnosis. Findings reported early failure and subsequent revision knee surgery after primary TKA. In a younger patient cohort and commonly in female TKA patients, requirement for revision due to instability was frequently reported. In addition, early revision at a younger age highlighted the severe implications of an unstable knee.