I. Background Osteochondral injury can be a complication of a patient’s late ankle injury. Chronic talar pain is usually present, often accompanied by ankle trauma. For acute and early unseparated osteochondral injuries, a period of bracing and non-weight-bearing treatment is recommended. In contrast, unstable defects and those who fail conservative treatment require surgical treatment. Osteochondral injury of the talus is one of the main causes of chronic pain in the ankle joint, mostly in men, with about 10% of cases being bilateral. Repeated sprains and fractures of the ankle joint may be the main cause. Injuries to the talar osteochondral cartilage can be divided into anterolateral foraminal injuries and posterior medial foraminal injuries. The medial fornix injury is the most common and involves a greater degree of involvement, followed by the lateral fornix osteochondral injury. There are two common types of osteochondral injuries of the talus. One is the anterolateral injury to the apex of the talus, which is formed by the compression of the fibula during dorsiflexion and inversion of the ankle joint. The other is a posterior medial injury to the top of the talus, which is formed by compression with the tibial surface of the ankle joint during plantarflexion and inversion of the ankle joint. The trauma can be a single injury or a constant microtrauma. The typical presentation is persistent chronic ankle pain following a history of a previously existing ankle sprain. The pain is usually present at the specific site of the injury. Recurrent swelling, weakness, stiffness and popping may be present. Patients with frequent recurrent ankle sprains may complain of ankle instability. The skin point is blurred to palpation. The presence of pressure pain on the anterolateral aspect of the talar apex during plantarflexion of the ankle is suggestive of anterolateral talar osteochondral injury. In contrast, the presence of pressure pain on the anteromedial aspect of the apex of the talus during ankle dorsiflexion suggests posterior medial talar osteochondral injury. Detection of ankle instability includes the anterior drawer test and the inversion stress test. Ankle mobility is measured and compared with the contralateral side. Physical examination should exclude neurologic and vascular pain. In the acute phase of an ankle injury, combined ligamentous injuries and fractures of the fibula or distal tibia should also be excluded. Plain radiographs lack the ability to detect cartilage damage and cartilage dislocation, and CT also lacks the ability to detect articular cartilage damage. Bone scans can evaluate osteochondral injuries that are negative on plain radiographs. MRI has the ability to evaluate articular cartilage and subchondral bone damage and can detect damage to surrounding soft tissues. It has been reported that MRI is close to intraoperative findings of osteochondral injuries of the talus with arthroscopy. In 1959, Berndt and Harty performed the first staging of osteochondral injuries using plain X-rays: Stage I; subchondral bone compression. Phase II: partial separation of osteochondral fragments. Stage III: complete separation of the osteochondral fragments without displacement. Stage 4: complete separation and displacement of the osteochondral fragments. Later, Loomer and Coworkers modified this staging and included a fifth stage: subchondral bone cyst. Hepple and his colleagues revised the MRI staging in 1999 based on Berndt and Harty’s staging. stage 1: represents only articular cartilage damage; stage 2A: represents articular cartilage damage and bone marrow edema in subchondral fractures; stage 2B: similar to stage 2A except without bone marrow edema; stage 3: represents separated osteochondral lamellae but without bone marrow edema. Stage 3: represents separated osteochondral fragments without displacement; Stage 4: displacement of osteochondral fragments; Stage 5: subchondral bone cyst formation. Pritsch et al. were the first to use arthroscopy to grade osteochondral injuries by evaluating the quality of the cartilage, and Cheng et al. further developed the arthroscopic staging of osteochondral injuries of the talus. Stage C: fibrosis or cartilage formation with fissures; Stage D: appearance of osteochondral lamellae or exposed bone; Stage E: separation of osteochondral lamellae without displacement; Stage F: separation and displacement of osteochondral lamellae. However, this evaluation of bone damage is still inadequate. Arthroscopic articular cartilage on the surface of the talus is flap-like (grade D) V. Treatment Clinical treatment strategies for osteochondral injuries of the talus vary greatly. From non-surgical treatment to biorepair and regeneration of cartilage, many recommend treatment based on the staging of the injury. Others recommend treatment based on the extent of the injury: injuries greater than 1.5 cm require surgical treatment. 1. Non-surgical treatment. For Berndt and Harty’s stage 1 patients, there is no disagreement about conservative treatment. Non-operative treatment consists of rest or avoidance of strenuous physical activity. Initially, non-weight bearing and bracing is required. Some reports suggest that stage 1 and 2 patients with Berndt and Harty need conservative treatment for more than 1 year before deciding on surgical treatment. 2. Surgical treatment. Surgery may be considered in patients who have failed conservative treatment or in stages 2-5 of Berndt and Harty. Surgical treatment of osteochondral injuries of the talus includes surgical excision with treatment to stimulate fibrocartilage growth, such as microfracture, grinding, or drilling through the cartilage. If the osteochondral fragments are large, drilling, bone grafting or internal fixation to protect the apex of the talus may be performed. Other methods are cancellous bone grafting or osteochondral grafting, which can be performed by autologous, allogeneic or cell culture. 3. Extracorporeal shock wave therapy. Extracorporeal shock wave therapy is mainly used to treat certain skeletal and soft tissue diseases in the sports department, such as delayed fracture healing, non-healing, femoral head necrosis, and tendon end disease such as calcific supraspinatus tendonitis, plantar fasciitis, Achilles tendonitis, etc. It has the advantages of being minimally invasive, safe, effective and inexpensive. Professor Xing Jianyan was the first to use extracorporeal shock wave therapy (ESWT) in combination with ankle arthroscopy to treat osteochondral injuries of the talus with very satisfactory results. Currently, ESWT has been used in our department to treat early femoral head necrosis, humeral epicondylitis and other sports system diseases, and has achieved satisfactory results. VI. Summary Early diagnosis of osteochondral injury of the talus requires some indications. Chronic ankle pain or dysfunction can be the result of damage to the subchondral bone of the talus and degeneration of the joint surface. The incidence of talar osteochondral injuries is still not well understood and is generally associated with trauma. Inversion of the ankle joint with dorsiflexion will damage the lateral aspect of the talar apex, and inversion with plantarflexion will damage the medial aspect of the talar apex. Early stable injuries (stage 1 or 2) can be treated conservatively, while (stages 3-5) require surgical treatment.