The study is being conducted to evaluate the efficacy, safety of HR021618 and to explore the reasonable dosage of HR021618 for Pain Management after Orthopaedic surgery.

Inclusion Criteria:

1. Able and willing to provide a written informed consent
2. Subjects requiring elective Orthopaedic surgery
3. Male or female
4. Meet the weight standard
5. Conform to the ASA Physical Status Classification Postoperative randomization criteria Exclusion Criteria

1、 Sufficient pain to require IVanalgesia assessed by NRS ranging 2、 No evidence of organ insufficiency, or any other abnormality, during or following surgery

Exclusion Criteria:

1. History of major surgery
2. History of active or high-risk bleeding disorders
3. History of myocardial infarction or coronary artery bypass
4. History or clinical manifestations of significant renal, hepatic, cardiovascular, metabolic, neurologic, psychiatric, or other condition that would preclude participation in the study
5. Abnormal values in the laboratory
6. Have a known allergy to meloxicam or any excipient of HR021618, , aspirin, other non-steroidal anti-inflammatory drugs (NSAIDs) or to any peri- or postoperative medications used in this study
7. Use other drugs that affect the analgesic effect before randomization, and the time from the last use to randomization is shorter than 5 half-lives
8. Planned/actual admission to the intensive care unit
9. Pregnant or nursing women
10. No birth control during the specified period of time
11. Participated in clinical trials of other drugs (received experimental drugs)
12. The inestigators determined that other conditions were inappropriate for participation in this clinical trial