Osteochondral lesions (OCLs; Osteochondral lesions) are injuries to the subchondral bone and cartilage of the joint, and their causes include multiple roles: injury, ligamentous laxity instability, ischemic necrosis, force line abnormalities, endocrine disorders, and others. Because its natural history is unknown, the disease has been historically referred to by various names: exfoliative osteochondritis, osteochondral fracture, exfoliative fracture, etc. So far there is no evidence of inflammation and the term exfoliative osteochondritis has been eliminated, while the names osteochondral fracture and exfoliative fracture only imply injury due to traumatic factors without reference to other causes of the lesion (e.g. osteonecrosis), so “osteochondral injury” is considered the most appropriate name at present. OCLs are most common in the lower extremity joints of the knee and ankle, with ankle lesions accounting for 4% of all osteochondral injuries1 and usually occurring at a younger age (734 patients, mean age 26.9 years)2 and most commonly at the anterolateral and posterior medial aspect of the talar apex. This can seriously affect quality of life and motor function. In recent years, the diagnosis of OCLs has gradually increased due to the availability of modern tests, including CT, joint CT, MRI, and SPECT-CT. With the abundance of examinations, treatment options have also started to improve. Ankle arthroscopy techniques allow for minimally invasive treatment operations (debridement, drilling, microfracture, etc.) along with diagnosis, and depending on the extent and scope of the lesion, also under direct vision after incision (mosaic cartilage grafting, autologous chondrocyte transplantation, etc.). Despite the large body of literature on OCLs (evidence levels II-IV), there is still a lack of authoritative guideline literature and orthopaedic surgeons must consider a combination of factors to choose a treatment modality, such as: age, lesion size, location, etc. In addition to physical symptoms, the clinical diagnosis should be based on weight-bearing orthopantomographies of the ankle joint. The traditional staging of OCLs is the imaging staging of osteochondral injuries of the talus proposed by Berndt and Harty3: Grade I: small area of compression; Grade II: incompletely stripped fracture mass; Grade III: completely stripped fracture without displacement; Grade IV: completely stripped fracture with intra-articular displacement. Other examinations such as CT, MRI, SPECT-CT and arthroscopy can also be used. The etiology of OCLs can be divided into traumatic and non-traumatic, with traumatic factors accounting for more than 80%.4, 5 The vast majority of acute OCLs are located at the anterolateral aspect of the talar apex, with severe inversion sprains, chronic ankle instability (CAI), or fractures being the most common traumatic factors.6 However, overall, OCLs are more common on the posterior medial aspect of the talus than on the anterolateral aspect. Because the mechanism of non-traumatic factors such as repeated microfractures, ischemic necrosis, genetic defects, endocrine disease, or systemic lesions leading to chronic OCLs (disease duration greater than two months) is unclear, patients should be noted clinically for the presence of imaging changes on the hindfoot force line. Many OCLs with unclear traumatic factors are referred to as “idiopathic” lesions. Treatment options are conservative (exercise restriction, nonsteroidal anti-inflammatory analgesics) limited to grade I and II lesions, but the literature reports variable results (0% to 100%).2 A META analysis synthesized the clinical outcomes of conservative treatment in 201 OCLs, with an efficiency rate of 45%7; for chronic lesions, the efficiency ranged from 41%2 (cast braking) to 59%8, 9 (allowing ankle motion ); conservative treatment appears to be somewhat more effective in younger patients, with the Bruns study showing an 85% effectiveness rate for conservative treatment in young adults compared with 65% for adults overall (level IV10 evidence). Most lesions in OCLs worsen if treated only conservatively, and Brndt and Harty reported that the final outcome of patients treated non-operatively was mostly poor, whereas 84% of patients treated surgically improved function3 (level IV evidence). Surgical treatment modalities include incisional and arthroscopic surgery, with operations including free body removal, lesion debridement, drilling and fabrication of microfractures, and osteochondral grafting. Incisional surgery sometimes requires an internal or external ankle osteotomy for adequate exposure, and arthroscopic surgery as a minimally invasive treatment can avoid the disadvantages associated with osteotomy. Primary fixation of acute osteochondral injuries 73% of acute injuries can be fixed with satisfactory results using buried screws, resorbable materials or other methods of fixing exfoliated fractures11. Debridement, lesion cleaning by removing necrotic tissue and free bodies from the lesion, and joint irrigation can manage small lesions with satisfactory short-term clinical results. The only secondary evidence in the literature states12: 33 patients who underwent arthroscopic debridement, microfracture and autologous osteochondral grafting, respectively, showed no difference in clinical outcome at 12 and 24 months. Reverse drilling for grade I and II lesions, reverse drilling of the articular surface from the tarsal sinus can drill through sclerotic and cystic changes in the subchondral bone and induce bone marrow cell growth and revascularization, resulting in the formation of new healthy subchondral bone and the fibrocartilage tissue on its surface. Level IV evidence suggests an efficiency of 81%.13, 14 Kono 14 reported that in early OCLs, reverse drilling was superior to cis-drilling (Level IV evidence). Microfracture creation by drilling enables bone marrow stem cells to enter the lesion area and gradually differentiate into chondroblasts, chondrocytes, and fibroblasts, resulting in a hyaluronic acid-free fibrocartilage matrix that lacks the viscoelastic qualities of hyaline cartilage. The limitations of the microfracture technique are: lesions less than 1.5 cm in extent and lesion depth less than 7 mm.15 The current efficiency of the microfracture technique ranges from 77% to 96%.16, 17 (all Level IV evidence). The combination of microfracture technique and lesion debridement is superior to lesion debridement alone.4 Autologous osteochondral grafting For grade III and IV OCLs, full-thickness autologous osteochondral bone can be taken from the donor area (lateral epicondyle or intercondylar fossa of the femur) for grafting. Level IV evidence studies have shown excellent treatment outcomes (89%-100%).18, 19 However, osteochondral bone obtained from the donor area does not exactly match the cartilage of the talus in terms of morphologic contour, biology, and mechanical properties, and the technique required to restore articular surface curvature and continuity at the talar lesion defect is very demanding.Gobbi20 (Level II evidence) and Draper21 (Level III evidence) concluded that There is no significant difference in clinical outcomes between autologous osteochondral grafting and drilling to create microfracture techniques. Allogeneic osteochondral grafts may be attempted for large OCLs. Prospective long-term studies have concluded that fresh allogeneic osteochondral grafts of the knee yield satisfactory results (85% femoral, 80% tibial Grade II evidence).21 Fewer reports have been made on allogeneic osteochondral grafts of the talus, with Gross reporting a survival rate of 66% at 11-year follow-up (Grade III evidence).22 Autologous chondrocyte transplantation is performed by obtaining autologous chondrocytes, which are cultured in vitro for 2-5 weeks and then implanted back into the site of the cartilage defect. The current standard procedure for this technique is to cover the transplanted chondrocytes with a double layer of collagen membrane and fixate them in the cartilage defect area with fibrin glue after the lesion has been cleaned and drilled to form a microfracture. In cases of combined force line abnormalities or chronic ankle instability, surgery should be performed simultaneously to correct these factors. The indications for this technique are: lesion size greater than 1.5 cm and patient age less than 55 years.23 Osteoarthritis or corresponding defects in the tibial talar contact surface (Kissing tibia-talor lesions) are contraindications. The results of the intermediate follow-up are encouraging, with Whittaker reporting an excellent rate of 90%24 and Koulalis25 even reporting a success rate of 100% (both as level IV evidence). However, this technique requires a longer recovery time and is very costly compared with other methods. CONCLUSION: Overall, conservative treatment can be attempted first for early lesions (grades I and II), and surgical intervention is recommended for grade III and IV lesions or grade I and II lesions that fail conservative treatment. For acute exfoliation fractures should be fixed. The following options are available for the management of cartilage lesions: autologous chondrocyte graft, microfracture, and autologous osteochondral graft; and for the management of subchondral bone lesions: autologous osteochondral graft, autologous bone graft, and reverse drilling. Since the literature on talar OCLs is updated almost every month, physicians are advised to obtain continuing education from sources such as high-grade literature, reviews and META analysis, and advanced forums.