Local infiltration analgesia versus continuous interscalene brachial plexus block for shoulder replacement pain: a randomized clinical trial.

BACKGROUND: Shoulder replacement involves significant post-operative pain, which is often managed by continuous interscalene brachial plexus block. Catheter displacement and complications limit the beneficial effect of the block. Local infiltration analgesia (LIA) has provided good results in knee replacement. We aimed to assess the effectiveness of LIA for pain after shoulder replacement.

METHODS: Patients scheduled for primary shoulder replacement under general anaesthesia were randomized to receive either local infiltration analgesia (LIA) (150 ml ropivacaine 0.2 % with epinephrine intra-operatively) or interscalene brachial plexus catheter (ISC) (ropivacaine 0.75 %, 7 ml bolus followed by 48-h 5 ml/h infusion). The primary outcome was opioid consumption during the first 24 post-operative hours. Secondary outcomes were pain ratings, supplementary analgesics, and side effects for 3 days, and complications until 3 months after surgery.

RESULTS: Data were analysed for 61 patients (LIA 30, ISC 31). Twenty-four-hour opioid consumption was higher in the LIA group compared with the ISC group: median (IQR) 95 mg (70-150 mg) versus 40 mg (8-76 mg) (P = 0.0001). No significant difference in opioid consumption was found between groups during the following 3 days. The LIA group had higher pain scores at 0, 2, 4, and 8 h. Two patients in the ISC group had long-lasting complications.

CONCLUSIONS: The LIA technique cannot be recommended for shoulder replacement unless substantially modified. Occurrence of inadequate analgesia and complications following interscalene brachial plexus block prompt further studies into pain management after shoulder replacement.