To compare the clinical outcomes of CAI patients with and without lateral ankle avulsion fracture after ligament repair/reconstruction, and to analyze the risk factors associated with the outcome.

80 patients with external ankle ligament injury without avulsion fracture and 40 patients with external ankle ligament injury combined with avulsion fracture were treated by surgery in our department. The outcomes included Karlsson score, VAS, AOFAS and Tegner score. The outcomes were compared between the two groups, and the risk factors were analyzed.

Inclusion Criteria:

1. Age 18-60 years old
2. Chronic pain or instability in the ankle, injury to the lateral collateral ligament of the ankle determined by MRI examination of the ankle, and distal avulsion fracture of the fibula indicated by CT examination.
3. Patients with poor results after more than 3 months of conservative treatment with rest/topical/oral non-steroidal anti-inflammatory drugs
4. Patients voluntarily participate in clinical trials, sign informed consent, and can cooperate with clinical follow-up

Exclusion Criteria:

1. Persons who have participated in clinical trials of other drugs or medical devices within the last 6 months
2. Malalignment of ankle joint force (varus or valgus >5 degrees)
3. Chronic specific synovitis (rheumatoid, pigmented villonodular synovitis, etc.)
4. Patients with joint fibrosis, joint stiffness, and obvious limited movemente. Moderate to severe osteoarthritis (Takakura stage III or IV)

f. Patients with contraindications to MRI g. Hemophiliacs h. Patients with systemic conditions that cannot tolerate surgery

Patients with chronic lateral ankle instability with or without lateral ankle avulsion fracture meeting surgical indications.