A high tibial osteotomy (HTO) is a joint-preserving procedure that can be used to treat symptomatic unicompartmental cartilage disorders in the presence of limb malalignment.» Appropriate patient selection and careful preoperative planning are vital for optimizing outcomes.» Based on past literature, correction of varus malalignment to 3°to 8°o f valgus appears to lead to favorable results. Recently, there has been growing awareness that it is important to consider soft-tissue laxity during preoperative planning.» Although there has been a recent trend toward performing openingwedge rather than closing-wedge or dome HTOs for unicompartmental osteoarthritis, current data suggest that all 3 are acceptable techniques with varying complication profiles. » Based on current evidence, an HTO provides pain relief, functional improvement, and a high rate of return to sport, with reported survivorship ranging from 74.7% to 97.6% and 66.0% to 90.4% at 10 and 15 years, respectively.Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSREV/A794).