Robotic arm-assisted bi-unicompartmental knee arthroplasty maintains natural knee joint anatomy compared with total knee arthroplasty: a prospective, randomised controlled trial

Unicompartmental knee arthroplasty (UKA) is associated with faster postoperative recovery than total knee arthroplasty (TKA), sparing cruciate ligaments and normal joint surfaces. Although registry data indicate that revision rates are higher following UKA than TKA, robotic arm-assistance can improve accuracy of implant positioning and restoration of normal kinematics, when compared to manual implantation. Bi-unicompartmental knee arthroplasty (Bi-UCKA) with manual implantation has been demonstrated to maintain native joint obliquity better than TKA, but not as well as UKAs. There has been no RCT to date examining whether the benefits of UKA hold true for robotic-assisted Bi-UCKA compared to TKA.