High tibial osteotomy (HTO) is successful in treating symptomatic varus arthritis of the knee. We present a case where ankle pain and instability were attributed to varus ankle malalignment. This was found to be secondary to constitutional varus of the proximal tibia but the patient's knee was asymptomatic. The decision to operate on an asymptomatic knee in the hope of improving ankle symptoms took a period of careful consideration, planning and discussion. HTO was performed without immediate complication and the patient reported an excellent outcome with marked improvement in Mazur's foot and ankle score from 18 to 85. In well selected and planned cases, HTO may be considered as an instrument of deformity correction with improvement in symptoms from joints distant to the surgical site.