1. Treatment of rotator cuff tear The rotator cuff tear is the most demanding part of the shoulder surgery. Rotator cuff degeneration is thought to be the largest cause of rotator cuff tear.

   As the field of shoulder surgery evolves, the diagnosis and surgical treatment of the rotator cuff tear was increased. Repair and reconstruction of the rotator cuff tear annually more than 300,000 have been performed according to US statistics.

   Rotator cuff repair is a successful procedure, both objectively and subjectively, with regard to pain relief and functional outcome.

2. postoperative pain management after rotator cuff repair Shoulder surgeries are associated with a level of postoperative pain requiring opioid use for several days. The opioid requirements after shoulder surgery have been reported to be similar to those required after gastrectomy or thoracotomy, which might cause several opioid-related side effects, such as nausea and vomiting, pruritus, urinary distention, and constipation. Although the introduction of arthroscopy has reduced postoperative pain, a considerable proportion of patients suffer from moderate to severe acute postoperative pain, as its benefit is typically apparent after a few days. Consequently, proactive pain control is also required during the first 24-48 h after arthroscopic shoulder surgeries, just like in open surgeries. Adequate pain management during the immediate postoperative period is not only important for patient satisfaction and well-being, but also for facilitating postoperative rehabilitation and preventing persistent postsurgical pain.

Recently preoperative intravenous vitamin C has shown to increase the analgesic effect after otorhinolaryngologic surgery and thoracic surgery. Vitamin C is a water-soluble and known to have anti oxidant action, and fewer side effects.

However, there is no report about the analgesic effect of vitamin C after arthroscopic rotator cuff repair.

The purpose of this trial was to compare the effects of a intravenous vitamin C injection on postoperative pain and opioid consumption versus non-treated group after arthroscopic rotator cuff repair.

Inclusion Criteria:

• Rotator cuff tear patients undergoing arthroscopic rotator cuff tear

Exclusion Criteria:

• age <45 or >80
• allergies to medications used in the study
• history of renal diseases, a coagulation abnormality, a hepatic disease, or drug abuse
• definite radiographic evidence of osteoarthritis of the glenohumeral joint
• inflammatory arthritis including rheumatoid arthritis
• a history of acute trauma
• systemic conditions associated with chronic pain
• a history of infection
• an inability to understand the questionnaires