Continuous vs Liposomal Bupivacaine Interscalene Block for Proximal Humeral Fracture (CLIP)

Restricted range of shoulder motion following ORIF is a potential complication that severely affects the patients\' functional outcome and should be actively avoided by means of adequate pain control in addition to early mobilization and physiotherapy. Peripheral nerve blocks, which can be given as a single injection or continuous infusion via an indwelling catheter, are analgesic options to be considered. Interscalene Block (ISB) is the regional analgesia of choice for the shoulder and proximal humerus region. While continuous infusion (aka continuous nerve block) offers the advantage of a longer duration of analgesia compared to a single injection of standard local anaesthetic, it is associated with an inherent risk of catheter displacement, dislodgement, obstruction, and infection. Compared to Standard Bupivacaine (SB), Liposomal Bupivacaine (LB) is a formulation designed to prolong the duration of action to up to 72 hours by slow release of bupivacaine from the multi-vesicular liposomes. Several studies have demonstrated satisfactory analgesic effects of liposomal bupivacaine given as local surgical site infiltration over placebo. However, the effects of single injection of liposomal bupivacaine given via local surgical site infiltration compared to continuous nerve block have been inconsistent. Administrating liposomal bupivacaine directly to peripheral nerve blocks is a potentially effective approach that has not been extensively studied. ISB with single shot liposomal bupivacaine has been shown to provide superior postoperative analgesia compared to ISB with injection of standard bupivacaine or placebo. ISB with liposomal bupivacaine could perhaps prolong and improve postoperative analgesia without the potential problems with continuous nerve blocks. The analgesic effect of ISB with single shot liposomal bupivacaine versus continuous ISB with standard bupivacaine has not been previously investigated. The aim of this study is to compare the analgesic effect of these two analgesic modalities for plate fixation of proximal humerus fractures.