Kuroda Y, et al. - Authors ascertained the association between the change in joint line height calculated from the resected bone and insert thickness during surgery and the change in limb alignment following unicompartmental knee arthroplasty (UKA), presuming that joint line elevation was associated with the change in limb alignment. A significant moderate-positive correlation of the medial joint line elevation of the tibia (MJLET) measured during surgery with the change in limb alignment following medial UKA was seen. Postoperative limb alignment after UKA by considering, intraoperatively, both the insert thickness and the depth of resection at the proximal tibia could be predicted by the surgeon for clinical relevance, thereby, minimizing technical error to obtain an optimal alignment after UKA.