3. DISCUSSION
In these cases, HTO was an effective procedure to treat medial osteoarthritis in co-directional varus deformities at the knee and ankle of the same leg. Re-alignment of the proximal tibia leads to changes in ankle pressure, which could be beneficial in guiding the treatment of patients with medial osteoarthritis of the ankle.
HTO may influence the alignment and symptoms of the ankle joint. The effects of the HTO on the biomechanics of the ankle joint remain controversial. Several studies reported that the correction of severe varus deformity of the knee joint with HTO or TKA could result in pain and osteoarthritis progression of the ankle joint.5,8,9 Jeong and SooHoo8reported the case of a patient with persistent ankle pain after bilateral HTO for the treatment of osteoarthritis in both knee joints, which was treated with a corrective supramalleolar osteotomy of the ankle. Lee and Jeong5 reported that 21.8% of the patients had newly developed or progressive ankle arthritis after TKA in a series of 142 TKA cases. Graef et al.9 reported that the excessive correction of knee malalignment after TKA was associated with worse postoperative function in the ankle joint. In contrast, Takeuchi et al.10 reported the successful treatment of 16 HTOs in ten patients with osteoarthritis of the ipsilateral knee and ankle joints. Elson et al.11 presented the case of a patient with medial ankle pain and lateral instability in whom an HTO was performed, resulting in significant resolution of the ankle symptoms. Recently, Kim et al.12 reported that the correction of a knee varus deformity with HTO or TKA could improve the symptoms of medial ankle arthritis but could worsen lateral ankle arthritis. These reports corresponded to improvements in the symptoms of medial osteoarthritis in the ankle joint following HTO in our cases.
In well-planned and selected cases, HTO may be effective in treating not only the knee but also overload of the ankle in patients with ipsilateral double-joint osteoarthritis.