Objective To discuss the clinical outcome of tibiotalocalcaneal arthrodesis using lateral malleolus osteotomy and fixation with proximal humeral internal locking system (PHILOS). Methods From December 2008 to March 2010,11 patients with ankle arthritis were treated by tibiotalocalcaneal arthrodesis.They were 7 men and 4 women with an average age of 48.1 years (from 33 to 67 years).There were 6 cases of post-traumatic arthritis,3 cases of osteoarthritis and 2 cases of avascular necrosis of talus.The average disease duration was 2 years (from 1 to 3 years).Three patients were complicated with ankle varus and one patient with ankle valgus.According to the American Orthopaedic Foot & Ankle Society (AOFAS) scoring system,the preoperative ankle and hindfoot scores averaged 45.5 ± 11.1 points(from 30 to 64 points).Lateral malleolus osteotomy and internal fixation with PHILOS were performed in all patients. Results Superficial wound infection occurred in one patient which was cured after dressing changes.The other incisions healed by first intention without complications.Ten patients were followed up for 24 months on average (from 12 to 36months).The X-ray films showed that hone fusion was obtained at 12 weeks postoperation (from 10 to 16weeks) on average. The symptoms were relieved completely,without complications of implant failure,nonunion or malunion,in all patients at the last follow-up.The postoperative AOFAS ankle and hindfoot score at the last follow-up was 80.1 ± 7.4 points,significantly higher than the preoperative one ( t =27.101,P =0.000). Conclusion Tibiotalocalcaneal arthrodesis with lateral malleolus osteotomy and PHILOS fixation is technically simple and easy to handle,but it can provide rigid fixation and result in a high fusion rate and a good clinical outcome.