The Addition of Diclofenac to a Multimodal Pain Control Regimen Decreases Postoperative Pain and Opioid Consumption

Total knee arthroplasty (TKA) is a commonly-performed orthopaedic procedure in the United States. However, inadequate postoperative pain management following TKA has been associated with a number of negative consequences, including chronic postoperative pain requiring long-term opioid use. Multimodal pain control is a recently-popularized means of maximizing analgesia and postoperative outcomes. We aimed to evaluate the outcomes of a multimodal pain regimen incorporating diclofenac, including: 1) length of stay (LOS); 2) pain intensity; and 3) opioid consumption in primary TKA patients.

A prospective cohort study was performed. All patients scheduled for primary TKA by a single surgeon between March 1, 2017 and August 31, 2017 were screened for study involvement, yielding 46 consecutive patients (52 TKAs). This study group was treated with a postoperative regimen of intravenous (IV) diclofenac, in addition to a perioperative pain control regimen including adductor canal blockade (ACB) and periarticular multimodal drug injection (PMDI). Postoperative outcomes in this group were compared to those of a matched cohort of 78 patients (88 primary TKAs) who had previously been treated with the same perioperative pain control regimen.

Patients prescribed a postoperative diclofenac regimen had lower mean LOS (2.10 vs. 2.33 days; p=0.053) and lower 24-hour postoperative pain intensity (76 vs. 104; p=0.056) as compared to the untreated group. The diclofenac-treated group had a significantly lower opioid consumption in the first 24 hours postoperatively than did their untreated counterparts (39.8 vs. 53.1 morphine milligram equivalents [MME]; p=0.041). In addition, 17 patients (18 TKAs, 35%) in the diclofenac group had zero opioid requirements during the first 12 hours postoperatively, and 12 of these patients (13 TKAs, 25%) continued to not require any opioids through the first 24 hours postoperatively.

In the midst of the rapidly-increasing rates of TKA in the US, multimodal pain control has emerged as an extremely effective means of maximizing postoperative patient outcomes. To our knowledge, this is the first study to evaluate the postoperative outcomes of TKA patients treated with a regimen of IV diclofenac. We demonstrate shorter LOS, decreased 24-hour pain intensity, and significantly decreased 24-hour opioid consumption in patients treated with adjunctive IV diclofenac compared to patients managed with our institution's standard perioperative regimen.