Pain medication purchases before and after total hip and knee arthroplasty: a register study of 329,743 arthroplasties

Abstract

Background and purpose: Total hip (THA) and knee (TKA) arthroplasty are effective pain treatment in osteoarthritis; however, there are patients with long-term pain and in need of analgesics. We studied purchases of paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), opioids, and neuropathic pain medication before and after THA or TKA.
Patients and methods: We searched all THA (n = 149,158) and TKA (n = 180,585) cases in Finland between the years 1998 and 2018 and the drug purchases made by patients during 1997–2018 using linked Finnish register data. Drug purchases were studied in 3-month periods.
Results: The purchases of all analgesics increased from 3 years before operation to 3 months before operation. Around the time of THA or TKA, the purchases of all analgesics spiked to 7–56%, depending on drug. The purchases of all analgesics decreased rapidly during the first 6 months postoperatively. Purchases of paracetamol, NSAIDs, and opioids at 6 months postoperatively (6–23%) were lower than they were at 3 months preoperatively. At 3 years postoperatively, only paracetamol purchases were lower (15–18%) postoperatively than they were 3 years before arthroplasty. NSAID, opioid, and neuropathic pain medication purchases remained higher (4–14%).
Interpretation: THA and TKA stop and reduce the preoperative increases in purchases of paracetamol, NSAIDs, and opioids. The purchases of pain medications by THA and TKA patients 1 year after operation are close to those in the general population.