Regional Nerve Blocks for Primary Total Knee Arthroplasty in Chronic Opioid Patients

Postoperative pain control after total knee arthroplasty (TKA) remains challenging, particularly in patients utilizing chronic opioids preoperatively. Our study aimed to evaluate the effect of regional nerve blockade on perioperative pain control outcomes after TKA in patients using or not using chronic preoperative opioids. A retrospective review of our institutional database identified 434 chronic opioid patients defined as documented ongoing use greater than 3 months prior to contemporary TKA. Patients were 1:1 matched to nonopioid users based upon age, sex, body mass index, and regional block type (single-shot adductor canal block [ACB, 29%], 3-day ACB catheter [31%], or no block [41%]). All patients underwent primary TKA using periarticular injections and contemporary multimodal pain management. Immediate and 90-day postoperative outcomes, including Knee Osteoarthritis Outcome Score, Junior (KOOS, Jr), were compared via univariate analysis among the matched cohort and regional block type among chronic opioid patients. Chronic opioid patients demonstrated higher inpatient opioid use than controls (90 vs. 65 oral morphine equivalents [OMEs], respectively, p < 0.01), but no significant differences existed in length of stay (LOS), discharge pain scores, 90-day readmission or KOOS, Jr (all p ≥ 0.05). When comparing chronic opioid patients according to block type, those receiving no block had the highest LOS (1.6 days, p < 0.01), discharge pain score (5.0, p < 0.01), and inpatient opioid use (80 OMEs, p < 0.01) compared with either ACB. The subgroup receiving an ACB catheter demonstrated a significantly higher 90-day readmission rate (9%, p < 0.05). Patients utilizing chronic opioids preoperatively require more opioids in the immediate postoperative period after TKA compared with nonopioid users despite contemporary modalities. Nonetheless, the use of any type of ACB provides improved pain control in these patients.