Risk Factors and a Predictive Nomogram for Acute Moderate-to-severe Postoperative Pain After Achilles Tendon Surgery

Inclusion Criteria: 1. Age ≥ 18 years; American Society of Anesthesiologists (ASA) physical status classification Ⅰ\~Ⅲ; 2. Clinically diagnosed with Achilles tendon rupture, Achilles tendinopathy, insertional Achilles tendinitis, Haglund's deformity, or other Achilles tendon disorders; 3. Undergoing open or arthroscopic Achilles tendon surgery; 4. Conscious and able to cooperate in surgery and postoperative pain assessment; 5. Complete and accessible case data related to surgery, anesthesia, and postoperative pain assessment; 6. Completion of at least 24 hours of standardized pain monitoring and clinical follow-up after surgery Exclusion Criteria: 1. Missing or incomplete key clinical data such as pain assessment, surgery and anesthesia; 2. Failure to complete 24-hour standardized pain monitoring after surgery; Perioperative unplanned secondary surgery or transfer to the intensive care unit (ICU); 3. Patients with mental illness, cognitive dysfunction, or language communication barrier; History of alcohol or drug addiction Pain due to other acute or chronic diseases; 4. Bilateral Achilles tendon surgery Concurrent surgery for other lower extremity injuries