In this episode, Marc and Mo highlight a recent large database study from The Hospital for Special Surgery and use it as a springboard to discuss a number of issues related to the appropriateness, timing, and investigation of knee arthroscopy in patients with degenerative disease. • What is the relationship between the timing of knee arthroscopy and the rates of revisions and complications following TKA? Is there a recommended time interval between knee arthroscopy and TKA that can be used to inform clinical decision-making? • Is the use of arthroscopy in the presence of knee OA even evidence-based to begin with? What would be the specific situations in which arthroscopy would definitely be indicated? • What are the weaknesses of the insurance database approach to studying this topic? How should we advise residents or young academic faculty with regard to the issues that are associated with this study design? What confounders must be considered in the interpretation of the results? • If the goal is to delay TKA for as long as possible, what are the top 3 evidence-based interventions that we have in our armamentarium today? OrthoJOE Mailbag: feedback, comments, and suggestions from our audience can be sent to orthojoe@jbjs.org Links: • Gu A, Fassihi SC, Wessel LE, Kahlenberg C, Ast MP, Sculco PK, Nunley RM. Comparison of Revision Risk Based on Timing of Knee Arthroscopy Prior to Total Knee Arthroplasty. J Bone Joint Surg Am. 2021 Apr 21;103(8):660-667. doi: 10.2106/JBJS.20.00218. PMID: 33849048. Link • Jones MH. Indications for Knee Arthroscopy in Patients with Osteoarthritis: Commentary on an article by Alex Gu, MD, et al.: "Comparison of Revision Risk Based on Timing of Knee Arthroscopy Prior to Total Knee Arthroplasty". J Bone Joint Surg Am. 2021 Apr 21;103(8):e33. doi: 10.2106/JBJS.21.00074. PMID: 33849051. Link • Richardson SS, Schairer WW, Sculco TP, Sculco PK. Comparison of Infection Risk with Corticosteroid or Hyaluronic Acid Injection Prior to Total Knee Arthroplasty. J Bone Joint Surg Am. 2019 Jan 16;101(2):112-118. doi: 10.2106/JBJS.18.00454. PMID: 30653040. Link • OARSI Guidelines: https://oarsi.org/education/oarsi-guidelines-0