Effectiveness of distal tibial osteotomy with distraction arthroplasty in varus ankle osteoarthritis

Abstract Background: Advanced to end-stage ankle osteoarthritis in highly active older individuals has traditionally been treated using tibiotalar arthrodesis. With tibiotalar arthrodesis, high levels of pain-free function are possible; however, there is a loss of ankle joint movement and a risk of future arthrosis in the adjacent joints. Distraction arthroplasty is a simple method that allows joint cartilage repair; however, the results are currently mixed, with some reports showing improved pain scores and others showing no improvement. Distal tibial osteotomy (DTO) without fibular osteotomy, a type of joint preservation surgery, has garnered attention in recent years. However, to our knowledge, there are no reports on DTO with joint distraction using a circular external fixator. Therefore, the purpose of this study was to examine the effect of DTO with joint distraction using a circular external fixator on ankle osteoarthritis. Methods: A total of 21 patients with medial ankle arthritis were examined. Arthroscopic synovectomy and a microfracture procedure were performed. Subsequently, angled osteotomy and correction of the distal tibia were performed. After ankle conditions improved, stabilization of the ankle joint was performed. An external fixator was used in all patients. In addition, joint distraction of about 5.8 mm was performed. All patients were allowed full weight-bearing walking immediately after surgery. Results: The anteroposterior mortise angle during weight-bearing, lateral mortise angle during weight-bearing, and talar tilt angle and anterior translation of the talus on ankle stress radiography significantly improved (P < 0.05). In addition, signal changes on magnetic resonance imaging improved in all patients. Visual analogue scale and American Orthopedic Foot & Ankle Society scores also improved significantly (P < 0.05). No severe complications were observed. Conclusion: DTO with joint distraction may be useful for older patients with a high physical activity level as a joint-preserving surgery for medial ankle osteoarthritis. Level of evidence: Level IV, retrospective case series Key words : distal tibial osteotomy, medial ankle arthritis, joint distraction, circular external fixator