Custom Peri-Articular Injection Cocktail Preparations are Associated with a Major Financial Burden in Total Joint Arthroplasty.

Introduction: Periarticular injections (PAI) are an important component in modern multimodal pain management protocols for total joint arthroplasty. There is a wide variety of formulas reported in the literature, from simple bupivacaine to surgeon-specific "cocktails" that include up to seven different components. Due to the broad lack of standardization in PAI formulations, this study aimed to evaluate the cost savings associated with our institution's transition to a standardized approach while ensuring no adverse impact on inpatient pain outcomes.

Methods: We identified 16 unique PAI formulations used by 20 arthroplasty surgeons at a single institution, each prepared by the institution's pharmacy and nursing staff. Costs associated with the PAI formulations included the cost of each medication comprising the "cocktail," and the labor cost associated with their preparation. These costs were compared to the in-operating room preparation of bupivacaine injections. An evaluation of the potential cost savings was extrapolated based on our annual total joint volume.

Results: The average surgeon-specific formulation costs $10.33 for ingredients alone, which is 435% higher than a bupivacaine injection and leads to an annual ingredient cost of $22,496.17 for PAIs. The preparation of these cocktails required a total labor cost of $93,600 annually. Taken together, the elimination of custom cocktails and the adoption of isolated bupivacaine translated into institutional savings of $116,096.17 per year. Inpatient pain scores were not significantly different between bupivacaine-only and surgeon-specific PAI formulations.

Conclusions: Surgeon-specific PAI formulations impose a large, somewhat hidden expense on hospital systems through the cost of sourcing medications and, in particular, the labor cost of preparing each unique combination. As bupivacaine-only PAI achieves satisfactory clinical outcomes for joint arthroplasty patients, the elimination of custom cocktails is of major benefit from a value-based care perspective.