Ischemic necrosis of the navicular bone (Köhler’s disease) First described by Köhler in 1908, and therefore called Köhler’s disease, it is a self-healing disease of the navicular bone of the foot that is seen as flattened, sclerotic, and irregularly thinned on radiographs. It occurs in children aged 3 to 7 years, with males outnumbering females (4:1), with bilateral onset accounting for about 1/4 to 1/3 of cases, and is often misdiagnosed as an infection. I. Etiology The etiology of this disease is related to mechanical external force.Köhler et al. believe that the tarsal navicular bone is the last tarsal bone to ossify in the foot bone, which constitutes the apex of the medial longitudinal arch of the foot, and is the site of concentration of stress in the foot, which suggests that the center of tarsal navicular bone ossification is heavily loaded. If the center of ossification is retarded, or if it is injured by trauma or fatigue during its fastest growth phase, extrusion to the center of ossification interrupts the blood supply into the central artery of the navicular bone, which can lead to ischemic necrosis of the tarsal navicular bone. Biopsy shows that there are necrotic areas in the navicular bone, and dead bone resorption and new bone formation are seen at the same time. Symptoms and signs Complaints of foot pain and claudication, pain aggravated by weight bearing. Examination of the foot reveals swelling of the dorsum and medial aspect of the foot, tenderness, and restriction of midfoot movement. There may be inflammatory changes at the attachment point of the posterior tibial tendon. Third, the imaging performance X-ray shows that the navicular bone is dense, sclerosis, narrowing and destruction, irregular shape, or even fragmentation; navicular bone and talus and cuneiform bone gap widening; may be accompanied by acute fracture; dorsum of the foot to see mild soft tissue swelling. Late stage may show degenerative changes in the joint. After a few years, the shape returns to normal except for flattening of the navicular bone. CT and MRI are not necessary unless pain persists or the diagnosis is questionable. Intermittent symptoms may persist for years after diagnosis. Avoid running, jumping and prolonged weight-bearing. Non-steroidal anti-inflammatory drugs are the main therapeutic agents, and longitudinal arch shoe insert support and limb braking may reduce pain. Surgery is rarely required, and some authors have reported the use of medial tarsal artery implantation in the treatment of Köhler’s disease, which has been described as satisfactory. The disease is mostly self-limiting and usually resolves spontaneously. Repair occurs within 6 months at the earliest, most take 1-3 years, and in the vast majority of patients the navicular bone returns to full normalcy before the foot matures, leaving no deformity or disability. Deformity of the navicular bone may occur after symptoms have subsided.