Pain Scores After Total Knee Arthroplasty May Predict Chronic Opioid Use

Acute postoperative pain scores were found to be associated with chronic opioid use after total knee arthroplasty (TKA) in patients taking opioid medications prior to intervention, according to a study published in Regional Anesthesia and Acute Pain.

The preoperative and perioperative characteristics of 32,874 veterans who used opioid analgesics prior to TKA were examined. Study participants were categorized according to the acute pain scores they reported before surgery over a 3-day period (ie, ≤4 or >4 on a 0-10 scale). Rates of chronic opioid use (ie, mean >30 mg/day dose in morphine equivalents) starting 3 months after treatment, prescriptions at discharge, and postoperative vs preoperative dose category changes were examined.

In this cohort, 36% and 64% of patients reported high and low postoperative levels of acute pain, respectively. Chronic significant opioid use was identified in 21% of the cohort, and this rate was found to be greater in patients indicating high vs low postoperative acute pain scores. In the adjusted analysis, patients with lower vs higher acute pain scores had less chronic significant opioid use (12% vs 16%, respectively), smaller discharge prescriptions (P <.001), and greater opioid medications dose reductions (P <.001 for all).Hospital length of stay was found to be longer in patients with higher vs lower scores (51% vs 47%, respectively; P <.001). Dose escalation was found to be 15% less likely in patients reporting low vs high acute pain scores (odds ratio, 0.85; 95% CI, 0.80-0.91).

Limitations of the analysis include the high percentage of men in the cohort (>90%) and the use of patient data exclusively from Veterans Affairs, which may limit generalizability.

“[I]n a population exposed to preoperative opioid use, acute postoperative pain was associated with chronic opioid use after TKA, independent of discharge prescriptions. Scores reported by patients in the first few days after surgery can thus have prognostic value….[O]ur finding provides reasonable support for aggressive efforts to reduce acute postoperative pain,” concluded the study authors.

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Reference

Hsia H-L, Takemoto S, van de Ven T, et al. Acute pain Is associated with chronic opioid use after total knee arthroplasty [published online July 2, 2018]. Reg Anesth Pain Med. doi: 10.1097/AAP.0000000000000831