It has been 4 months since the fracture of navicular bone, and the ankle joint is still swollen, mostly caused by the soft tissue injury of ankle joint, poor alignment of fracture, improper rehabilitation treatment. 1. Soft tissue injury of ankle joint: when fracture of navicular bone occurs, it may also be accompanied by the surrounding tendons, fascia and other soft tissue injuries, the treatment of fracture does not treat the soft tissue injury, which will make the inflammatory reaction of ankle aggravate and thus the ankle joint is still swollen. 2. Poor alignment of the fracture: when the fracture is repositioned, poor alignment will lead to traumatic arthritis of the ankle, resulting in localized congestion and edema of the ankle, which will cause swelling of the ankle joint. 3. Inadequate rehabilitation treatment: If the fracture of navicular bone is not treated in a standardized way or the treatment plan is not appropriate, it will lead to the aggravation of local inflammatory reaction of ankle joint and the swelling of ankle joint. Therefore, in order to identify the cause of ankle joint swelling, it is recommended to go to the orthopedic department of the hospital in time.