The causes of varus type ankle arthritis still remain unknown. In other studies, usually, ankle arthritis develops secondary to trauma[4, 7, 14]. However, in this study, more patients recalled an old ankle sprain history. We thought that maybe it was because of the weak lateral ligament resulted in varus type ankle arthritis.
Takakura and Tanaka divided varus ankle arthritis into 4 stages, stage I, II, III (IIIA, IIIB) and IV[1, 2]. Did stage IIIB ankle arthritis develop directly from stage IIIA? This is controversial. We do not think all of the stage 3B ankle arthritis were evolved from stage 3A ankle arthritis. When the talus invert in ankle mortise, with long time of walking, the varus talus touch the tibia surface and abrade it gradually. So, maybe the stage IIIB ankle arthritis developed directly from stage II.
For varus ankle arthritis, especially Takakura stage III or IV ankle arthritis, previous studies has reported good results of ankle arthrodesis or ankle replacement[15–19]. However, ankle arthrodesis is a joint sacrifice method to treat ankle arthritis, which restrict ankle movement. In this study, the mean age of patients was 52.35 ± 8.05 years. The patients are relatively young, so ankle arthroplasty may not be suitable for them. These patients were still very positive and want to keep their native ankle joint. Osteotomy provided the possibility to preserve their native ankle joint.
We think the most important aspect of this kind of procedure is that there is enough residual articular cartilage. Ankle joints with more than 50% residual articular cartilage tends to get better prognosis than those are not. So, we did osteotomy procedure for this kind of ankle arthritis. We do not perform osteotomy surgery for stage IV ankle arthritis. Joint cartilage of stage IV ankle arthritis was always extensively destructed. For this kind of patients, even though realignment of ankle joint may alleviate symptoms, joint damage will progress soon.
Previous studies reported that it was contraindication if the varus ankle was rigid and could not be corrected to normal under fluoroscopic examination before the surgery[9, 20]. However, in our study, we concern more about whether the varus ankle could return to normal intraoperatively or not. We performed thorough release of ligaments and capsule around ankle joint if the varus deformity could not be corrected after osteotomy. After the release and debridement procedure, the ankle joint was flexible and we fixed it into neutral position with 1–2 K-wires, which were removed 6 weeks postoperatively. In this position, the medial ligaments were sutured and lateral ligaments were reconstructed. We think that whether the varus ankle could return to normal during operation matters more than preoperative condition. We care more about the joint cartilage than preoperative talar tilt angle. Of course, the larger the talar tilt angle is, the more difficult we achieve the parallel ankle joint surface.