Most patients experience moderate to severe pain after total knee arthroplasty (TKA). We hypothesized that intraoperative treatment of cut bone surfaces with local anesthetic (preimplantation immersion anesthesia, PIA) would lead to decreased postoperative pain and opioid consumption.
Records of 76 patients who underwent unilateral, cemented TKA were retrospectively reviewed. For PIA patients, surgical wounds were immersed in local anesthetic solution immediately prior to component implantation. Both PIA (n = 43) and control (n = 33) groups received multimodal pain management, including intra-articular local anesthetic injections. Endpoints were opioid consumption and mean pain scores for postoperative day (POD) 0, 1, and 2. Demographic, medical, and social factors were included in multivariate analyses.
PIA patients reported significantly lower mean pain scores than controls on PODs 0 and 1 (both P < .005). Pain scores on POD 2 were similar. PIA patients used 45%-33% less opioids on PODs 0, 1, and 2 (all P < .005). POD 0 pain scores showed a significant interaction between PIA treatment and preoperative opioid use (P = .013). On POD 1, PIA was the only factor associated with lower mean pain scores (P < .001). No factors were significant for POD 2. PIA was the only factor associated with lower postoperative opioid consumption on PODs 0 and 2 (both P < .005). For POD 1, PIA and increasing age (both P ≤ .005) were associated with lower postoperative opioid consumption.
PIA was associated with significant reductions in opioid use and mean pain scores after TKA.