Local Infiltration Analgesia Is a Mixed Bag

Less costly local infiltration analgesia offers similar pain relief as interscalene block in the first 24 hours after shoulder arthroplasty, but more pain after 8 hours and more intraoperative opioid consumption, according to a new study.

The study, “Local Infiltration Analgesia Versus Interscalene Block for Pain Management,” was published online on July 1, 2022, in The Journal of Bone and Joint Surgery.

“While providing effective analgesia following shoulder arthroplasty, an interscalene block has known complications. Local infiltration analgesia using ropivacaine has been successfully employed in other joint arthroplasties, but its efficacy in shoulder arthroplasty has not been studied extensively,” the researchers wrote.

Their study compared pain and opioid consumption between local infiltration analgesia and an interscalene block following primary shoulder arthroplasty. Seventy-four patients were randomized to one of the two research arms. The interscalene block used liposomal bupivacaine and the local infiltration analgesia injection included ropivacaine, epinephrine, ketorolac, and normal saline solution.

The researchers compared postoperative Visual Analog Scale pain scores, opioid consumption in morphine milligram equivalents and complications for the two groups. They used the mean pain scores during the first 24 hours postoperatively to test noninferiority of local infiltration analgesia against an interscalene block.

Data showed no significant difference between the two groups with respect to pain scores at any particular time point, except at the 8-hour time point. At this time point, the injection group had a higher pain score (p = 0.01). There was no significant difference in opioid consumption after surgery between the groups at all; however, intraoperative opioid consumption was higher in the injection group (p < 0.001).

Complications reported included one patient in the bloc group who developed transient phrenic nerve palsy and one patient in the injection group who developed dislocation after reverse arthroplasty due to noncompliance.

The noninferiority test showed that the injection group was noninferior to the block group. The mean procedure hospital charge was $1,718 for an interscalene block and $157 for local infiltration analgesia.

“Local infiltration analgesia and an interscalene block provided similar analgesia during the first 24 hours after primary shoulder arthroplasty. Local infiltration analgesia was associated with worse pain at 8 hours postoperatively and more intraoperative opioid consumption but was also substantially less costly,” the researchers wrote.

The clinical trial investigators included Michael Ewing, M.D., Haley Huff, B.S., Sally Heil, B.S., Matthew J. Smith, M.D., and H. Mike Kim, M.D., all from the Missouri Orthopaedic Institute of the University of Missouri in Columbia, Missouri. Robert R. Borsheski, D.O, of the department of Anesthesiology at the University of Missouri also contributed to the study.