The goal of this clinical trial is to evaluate the effectiveness and safety of autologous costal osteochondral transplantation in the treatment of Hepple Stage V talar osteochondral lesions, compared with autologous osteoperiosteal transplantation. The main question it aims to answer is:

• Whether autologous costal osteochondral transplantation can achieve better clinical outcomes and cartilage repair quality with lower donor site morbidity than autologous osteoperiosteal transplantation in the treatment of Hepple Stage V talar osteochondral lesions.

Participants will be randomly assigned to the intervention group (undergoing autologous costal osteochondral transplantation) or the control group (undergoing autologous osteoperiosteal transplantation). Both groups of participants will receive the same postoperative rehabilitation process and follow-up evaluation.

Inclusion Criteria:

• Symptomatic Hepple stage V talar osteochondral lesions with a lesion depth ≥5 mm and an AOFAS score ≤80 points;
• Failed conservative treatment for at least 6 months;
• Unilateral talar osteochondral lesions without corresponding lesions on the tibial side;
• Willingness to participate in this clinical trial and signing an informed consent form.

Exclusion Criteria:

• Combined with lower limb deformity.
• Combined with hip or knee joint diseases.
• Combined with ipsilateral ankle arthritis with joint space narrowing .
• Diagnosis of gouty arthritis of the ankle joint.
• Combined with osteoporosis (T score <-2.5).
• Other conditions considered inappropriate for participation in this clinical trial by the researchers.