Postoperative outcomes of mepivacaine vs. bupivacaine in patients undergoing total joint arthroplasty with spinal anesthesia

BACKGROUND: Spinal anesthesia (SA) has been previously associated with improved outcomes after total joint arthroplasty (TJA). The purpose of this study was to compare outcomes between various local anesthetics. METHODS: This was a retrospective study of 1,328 patients undergoing primary TJA with SA from September 2020–2021 at a single institution. Patients were grouped based on TKA or THA and further separated and analyzed in terms of anesthetic agents—mepivacaine (M), hyperbaric bupivacaine (HB), or isobaric bupivacaine (IB). Subgroup analysis of same-day-discharge (SDD) patients and low- (<11 mg) and high-dose bupivacaine was performed. Statistical significance was assessed at P<0.05. RESULTS: Mepivacaine use was associated with younger age, lower ASAs, and lower Charlson Comorbidity Index (CCI) scores in both THAs and TKAs. Postoperatively, significant differences were found between HB, IB, and M in LOS, the first PT ambulation distance and rates of SDD, and home discharge in both THAs and TKAs. No significant differences in outcomes were observed between high- and low-dose bupivacaine in THAs or TKAs. In SDD patients, a significant difference was found only in the first 6-clicks mobility scores. After controlling for age, BMI, sex, ASA, and procedure type, mepivacaine was found to be associated with shorter LOS, increased likelihood of SDD, home discharge, POD-0 ambulation, and, further, the first ambulation distance. No significant differences were observed in 6-clicks mobility scores, urinary retention, 30-day ED returns or 30-day readmissions. CONCLUSIONS: Both bupivacaine and mepivacaine are safe and effective local anesthetics for patients undergoing TJA as evidenced by low, similar rates of urinary retention and 30-day ED returns and readmissions. Mepivacaine does appeared to facilitate early ambulation, shorter LOS and home discharge and should be considered as the local anesthetic of choice for patients undergoing rapid recovery TJA.