The connection between patient pain and clinical orthopaedic outcomes has received much attention lately. Here are relevant findings from two recent studies:
–An in-press study of 48 patients (average age of 72 years) who underwent TKA found that those with low pain thresholds prior to surgery (as measured with VAS scores while a blood-pressure cuff was inflated over the proximal forearm) were more likely to have lower Knee Society pain and function scores two years after surgery than those with moderate or high pain thresholds. The authors use this test in preoperative workups, and they advise patients who grade the cuff stimulus as severe that “their clinical outcomes are expected to be inferior to [those of] other patients,” encouraging such patients to take that into account before consenting to surgery.
–Among more than 1,100 patients (average age of 67 years) who participated in the Multicenter Osteoarthritis Study (MOST), inflammation, as evidenced by synovitis and effusion, was associated with reduced pain thresholds. However, resolution of established inflammation did not deliver a significant change in pain thresholds over two years, leading the authors to conclude that “early targeting of inflammation is a reasonable strategy to test for prevention of sensitization and…reduction of pain severity.”
Most patients with hip osteoarthritis dream of a nutritional supplement that will improve their clinical symptoms. Findings from a new study of a soybean-avocado supplement suggest they’ll have to keep dreaming. However, relative to placebo takers, those taking 300 mg a day of a proprietary soybean-avocado supplement over three years were 20% less likely to experience a loss of joint-space width of 0.5 mm or more. Alas, there were no significant differences between the two groups in important patient-centered outcomes such as pain and the use of analgesics or NSAIDs. The industry-funded study of nearly 400 patients initially set out to determine changes in joint-space narrowing (JSN) between the two groups, but researchers amended the protocol to measure progression because JSN was found not to be a “quantitative linear normally distributed parameter.”