Patient-reported pain and function can vary widely during the years prior to knee replacement. New multicenter research decided to tease out several details.
The study, “Pain Medication Reporting and Patient-Reported Outcomes in the Years Prior to Knee Replacement: Challenges to Assessing Symptomatic Experiences,“ appears in the April 2018 edition of Osteoarthritis and Cartilage.
The authors wrote, “OAI [Osteoarthritis Initiative] participants who underwent KR [knee replacement] during 108 months follow-up were selected if they met common eligibility for knee OA DMOAD [disease-modifying osteoarthritis drug] RCTs [randomized controlled trials] prior to KR, including at least one knee with Kellgren and Lawrence grade of 2 or 3, medial minimal joint space width ≥2.5mm, and knee pain at worst in the past 30 days (4-9 on a 10 point scale, or 0-3 with pain medication)….”
C. Kent Kwoh, M.D., director of the University of Arizona Arthritis Center and co-author on the study, told OTW, “Our prior work on patient-reported measures of pain and function indicated that, on an individual patient level, there was substantial variability in these measures in the years leading up to knee replacement.”
“The reasons for variability were unclear.”
“Analgesics have the potential to modify patients’ reporting of pain and function and may contribute to the variability seen in patients’ reports of pain and function. In addition, patterns of analgesic use prior to joint replacement have been understudied.”
“In guidelines for the management of knee osteoarthritis, opioids are recommended as a last resort after other conservative measures have failed. We were interested in the patterns of usage of opioids in the years leading up to knee replacement.”
“The Osteoarthritis Initiative (OAI) is an observational cohort study on patients with and at risk of developing symptomatic knee osteoarthritis that includes detailed information on patient-reported measures of pain and function and medication use that is collected at annual visits. We used the publicly available OAI database to conduct this study.”
“Although there was an indication of an increase in use of opioids in the years prior to knee replacement, there was also marked variability in use of analgesics in the years leading up to joint replacement.”
“For some patients, at times there was switching to a stronger analgesic, while for others there was switching to a weaker analgesic.”
“On an individual patient level, there was also marked year-to-year variation in the use of stronger versus weaker analgesics. Also of interest was that one-third of individuals reported no use of analgesics in the OAI visit in the year prior to knee replacement. In addition, there was little relationship between the strength of the analgesic and the level of pain reported.”
Asked about the most difficult thing to tease out with regard to analgesic use and symptom reporting, Dr. Kwoh told OTW, “When patients are taking analgesics and report symptoms, it is unclear whether patients are reporting average pain while on the analgesic or breakthrough pain prior to the next dose of the analgesic.”
