Unicompartmental knee arthroplasty is an underused procedure in orthopaedic surgery due to its level of difficulty and the unpredictability of results, which can be related to component malalignment. New robotic arm technology has been developed to assist the surgeon in accurately and reproducibly preparing the femur and the tibia for a minimally invasive bone-sparing unicompartmental knee arthroplasty. This new procedure provides comprehensive three-dimensional planning of unicompartmental knee arthroplasty components, including soft-tissue balancing, followed by accurate resection of the femur and the tibia. This paper reviews this new technology.