Five-year implant survival requires sufficient five-year follow-up

Agreement: I Agree Body: Dear Editor, Mohammad and colleagues’ national target trial emulation is an important counterweight to the rapid uptake of robotic knee arthroplasty.¹ Yet the policy-relevant question is not whether a five-year Kaplan–Meier curve can be plotted, but how much five-year evidence supports it. The risk tables offer a crucial qualification: at five years, only 176 of 17,255 matched robotic total knee replacements and 67 of 4,580 robotic unicompartmental replacements remained at risk.¹ Mean follow-up in the matched robotic groups was approximately 2.5 years. Although…