Unicondylar knee arthroplasty (UKA) still polarizes and this even more when its indications and outcome for treatment of lateral osteoarthritis are discussed. Experience seems to be a key factor for success with this intervention. But this experience is hard to gather for a technique, indications of which are relatively scarce. Experience with medial UKA may help to achieve favorable outcome with treatment of the lateral compartment. However, not all the principles that apply for the medial side may easily be transferable to the lateral compartment. This article wants to highlight why lateral UKA may be challenging and aims to serve as a guide to secure indication and operation technique. The differences of lateral UKA in comparison with medial UKA will be presented and discussed. Moreover, the most recent technical developments will be presented. Navigation, patient-matched cutting blocks, patient-matched implants, and modern robotics were all designed to make the outcome of this procedure more predictable. Their application in practice will be presented and their potential to facilitate this procedure and to add to a secure outcome will be discussed in detail.