Hohloch L, et al. - This study examined the impact of the size of axis correction on functional outcome in patients undergoing a valgus high tibial osteotomy (HTO). As per observations, HTO represented a reliable treatment option for varus deformity in patients with concomitant cartilage damage or osteoarthritis of the medial compartment and, afforded satisfying functional outcome. In each patient, precise pre-operative planning regarding individual factors is mandatory; a pathology-based extent of correction results in favorable clinical outcome and a significant reduction in pain.