Arthroscopic shoulder surgery is a commonly performed minimally invasive surgery in which a camera (an arthroscope) is inserted inside the shoulder joint.

This surgery is responsible for moderate to severe pain. It may require the use of opioid analgesics in the acute phase. One of the components of this pain may be the postoperative hematoma.

Pain is one of the main causes of patient satisfaction failure after shoulder surgery. Finding ways to reduce this pain is a primary principle in the management of this surgery. Until now, this management requires the frequent use of morphine. However, this use of morphine may conduct to adverse effects (nausea/vomiting, constipation, malaise, sweating), and even public health problems such as addiction.

It is therefore interesting to look for ways to increase the patient's analgesia by other means, which will thus increase patient satisfaction and make his management more fluid. The effect on pain of hematoma reduction is rarely described in the scientific literature.

The hypothesis of this study is that the intraoperative administration of intravenous (IV) tranexamic acid can reduce the hematoma and thus decrease postoperative pain.The aim of this study is to demonstrate that the use of IV tranexamic acid intraoperatively, compared to a placebo (sodium chloride 0.9%), reduces postoperative pain after arthroscopic shoulder surgery.

Inclusion Criteria:

1 - Male or female aged 18 years old or more; 2- Patient requiring shoulder arthroscopy; 3 - Patient affiliated to a social security scheme; 4 - Patient informed on the study and who has signed the informed consent form.

Exclusion Criteria:

1. - Tranexamic acid contraindications (Hypersensitivity to the active substance or to any of the excipients, Acute venous or arterial thrombosis, Severe renal impairment, History of convulsions);
2. - Pregnant or breastfeeding patient;
3. - Patient under legal protection;
4. - Patient taking part simultaneously to another clinical trial.

The study will be conducted in a double-blind setting. The patient and the investigating surgeon will be blinded. The injection of the product will be performed by the anesthetist that will be aware of the injected product (tranexamic acid or sodium chloride).