Femoral Nerve Block vs Periarticular Bupivacaine Liposome Injection After Primary Total Knee Arthroplasty: Effect on Patient Outcomes.

CONTEXT Patients receiving femoral nerve blocks for total knee arthroplasty (TKA) have been shown to have a high incidence of postoperative falls, which has been attributed to weakening of the quadriceps muscles. Local injection of analgesic medication that allows for full motor function of the quadriceps and, therefore, better progress through inpatient physical therapy and decreased hospital stay, has been suggested as an option for postoperative pain relief. OBJECTIVE To compare the number of inpatient physical therapy sessions and hospital days needed in patients receiving periarticular injection of extended-release bupivacaine liposome vs femoral nerve block after TKA. METHODS Data were retrospectively reviewed from the records of patients who underwent bilateral primary TKA, in which femoral nerve block was administered at the first operation and periarticular injection of an extended-release bupivacaine liposome mixture at the second operation. An average of 2.3 years had passed between the 2 procedures. The number of inpatient physical therapy sessions and hospital days needed were compared between both procedures for each patient. RESULTS Sixteen patients (14 women) were included in the study, with a mean (SD) age of 63.8 (6.7) years. Compared with femoral nerve block, periarticular injection of analgesic medication resulted in fewer inpatient physical therapy sessions (femoral nerve block: mean [SD], 3.5 [1.3] sessions; periarticular injection: mean [SD], 2.3 [1.0] sessions; P=.002) and fewer hospital days (femoral nerve block: mean [SD], 1.9 [0.6] days; periarticular injection: mean [SD], 1.5 [0.6] days; P<.032). CONCLUSION Compared with femoral nerve block, periarticular injection of analgesia was found to quicken postoperative recovery in patients hospitalized for TKA. The use of periarticular injections in patients undergoing TKA could yield substantial cost savings given the high frequency of this procedure.