High tibial osteotomy (HTO) is a surgical procedure performed to relieve pressure on the damaged site of an arthritic knee joint. The procedure changes the alignment of the heel bone (calcaneus). This joint-sparing operation is successfully used for the correction of a misaligned joint knee in arthritic patients. Unlike a knee replacement that requires resection and replacement of the worn ends of the bone and, in the case of a total knee replacement, resection of the anterior cruciate ligament as well, an HTO preserves the joint and works by shifting the load from the worn, arthritic side of the joint to the unworn side. This is achieved by changing the shape of the tibia (shin bone) and therefore changing where weight is transferred across the knee. As an alternative to joint replacement, HTO provides years of pain relief in appropriate patients.