Pain catastrophizing and opioid use prior to knee arthroplasty

Opioid misuse, overdose and addiction has become a global public health crisis. According to the National Institute on Drug Abuse, more than 115 people in the USA die every day following an opioid overdose. Patients taking these powerful medications to manage chronic pain are no exception to opioid-related risks.

Whilst it may be assumed that patients who catastrophized pain prior to knee arthroplasty (KA) may report highest levels of opioid use post operation, a new study published in the Journal of Pain Research entitled Opioid use prior to knee arthroplasty in patients who catastrophize about their pain: preoperative data from a multisite randomized clinical trial, shows that this may not be the case.

The study sample consisted of participants 45 years or older with knee osteoarthritis and scheduled for a knee arthroplasty between 1 and 8 weeks. Participants were subject to a cognitive screen and had scored more than 16 on the Pain Catastrophizing Scale (PCS), and more than 5 on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale.

Patients with revision or bilateral knee osteoarthritis, inflammatory arthritis, fracture, malignancy, infection or with the intention of undergoing arthroplasty within 6 months of the index surgery were excluded from the study.

Riddle et al. reported that knee arthroplasty patients have the highest rate of postoperative opioid use compared with other major procedures. The authors highlight the risks of opioid use in this patient group including addiction, overdose and death.

Riddle et al. found that two factors are key indicators of persistent opioid use: preoperative opioid use and pain catastrophizing.

According to the authors “people who catastrophize about their pain prior to KA did not demonstrate significantly increased opioid use compared with estimates from heterogeneous KA samples previously studied. However, variation in the prevalence of opioid use across study sites was substantial. Patients at a greater risk of preoperative opioid use had a higher comorbidity burden, were younger, and more likely to be African American.”

Although the authors quantified the extent of the variation across the clinical sites and found these to be substantial, they were not able to determine the causes of this variation. The authors call for further studies to explore the issue of site variation in opioid use rates and the factors that drive this variation.

The authors also mentioned that “among patients who catastrophize about their pain, opioid use does not appear to be higher than the general population of patients who undergo knee replacement surgery.”

Dr Michael Schatman, Editor-in-Chief of the Journal of Pain Research, added “the authors' excellent investigation brings question to what may be a myth regarding catastrophization resulting in more opioid use. The authors should be commended for recognizing that opioid utilization patterns are far too complex to be explained by a single variable, as too many recent studies have suggested.”

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_{Keywords: knee arthroplasty opioid use pain catastrophizing pain pain management journal of pain research}