This study is evaluating whether the timing of an interscalene nerve block affects pain control and recovery after arthroscopic rotator cuff repair surgery.

An interscalene block is commonly used to reduce pain after shoulder surgery. However, it is not known whether administering the block before surgery or after surgery provides better outcomes. Participants undergoing arthroscopic rotator cuff repair are assigned to receive the interscalene block either before the surgical incision or after completion of the procedure.

The study compares postoperative pain levels, opioid medication use, length of hospital stay, and ultrasound imaging quality during block administration between the two groups. Functional recovery is also assessed using patient-reported outcome measures during follow-up.

The investigators hypothesize that administration of the interscalene block before surgery may provide superior early pain control and reduce postoperative opioid requirements while maintaining similar functional outcomes compared with administration after surgery.

Postoperative pain remains a major challenge following arthroscopic rotator cuff repair despite advances in multimodal analgesia protocols. Inadequate pain control may delay rehabilitation, increase opioid consumption, prolong hospitalization, and negatively affect patient satisfaction. Ultrasound-guided interscalene block has become a cornerstone of perioperative pain management for shoulder surgery because of its proven analgesic efficacy and favorable safety profile.

Although interscalene block is routinely used in clinical practice, the optimal timing of administration remains controversial. Administration before surgical incision may provide preemptive analgesic effects by attenuating central sensitization and reducing nociceptive input during surgery. In contrast, administration after completion of surgery has been proposed as a strategy to extend the duration of postoperative analgesia. Existing literature provides limited and inconsistent evidence regarding the comparative clinical benefits of these approaches in patients undergoing arthroscopic rotator cuff repair.

This study was designed to evaluate the impact of interscalene block timing within a contemporary shoulder surgery pathway. In addition to its potential influence on perioperative analgesia, the timing of block administration may affect procedural workflow and ultrasound visualization of relevant anatomical structures. Improved understanding of these factors may contribute to optimization of perioperative management strategies and support evidence-based recommendations for regional anesthesia practices in arthroscopic shoulder surgery.

Inclusion Criteria:

• Adults aged 18 years or older.
• Patients undergoing primary arthroscopic rotator cuff repair.
• Presence of a repairable small-, medium-, or large-sized rotator cuff tear confirmed by clinical and imaging evaluation.
• Receipt of an ultrasound-guided interscalene nerve block as part of perioperative pain management.
• Ability to provide informed consent and comply with study follow-up requirements.

Exclusion Criteria:

• Irreparable rotator cuff tears.
• Partial-thickness rotator cuff tears not requiring repair.
• Revision rotator cuff repair procedures.
• Concomitant shoulder procedures that could substantially influence postoperative pain or functional outcomes (e.g., shoulder arthroplasty, fracture fixation).
• Previous surgery on the affected shoulder.
• Contraindications to interscalene nerve block, including local anesthetic allergy, infection at the injection site, or severe neurologic disease affecting the brachial plexus.
• Chronic opioid use or opioid dependence before surgery.
• Inability to complete study questionnaires or follow the postoperative rehabilitation protocol.
• Missing baseline or follow-up data required for outcome assessment.

Adult patients undergoing primary arthroscopic rotator cuff repair for repairable rotator cuff tears at a single tertiary referral center. Participants received ultrasound-guided interscalene nerve block either before surgical incision or after completion of surgery according to routine perioperative practice.

Individual participant data will not be made publicly available because of institutional and ethical restrictions related to participant confidentiality and privacy protection.