Patients with more severe knee OA were less likely to show response to steroid injection after 6 months
Among patients with osteoarthritis, those with more severe knee damage on MRI were less likely to respond in the longer-term to an intra-articular steroid injection, according to a recent analysis.
Terence O'Neill, MD, from the University of Manchester in the United Kingdom, and colleagues included 188 patients with knee osteoarthritis (OA) and either moderate knee pain for at least 48 hours for the prior 2 weeks or a KOOS score of at least 7 out of 32. Researchers excluded patients with gout, septic arthritis, inflammatory arthritis, any life-threatening illness and those who had hyaluronic acid or steroid injections within the prior 3 months, knee surgery within the prior 6 months or any contraindication to MRI. For each patient, one knee was injected with 80 mg of methylprednisolone acetate without anesthetic. Researchers defined response as either a 20% positive change in KOOS pain score or a “slightly” better score on the 5-point Likert scale for pain, or a 50% change in KOOS. A musculoskeletal radiologist scored patients using the Kellgren-Lawrence (KL) scale and measured joint space narrowing (JSN) on a score of 0 to 3, with 3 being the most severe reduction in joint space. A maximal score was defined as the worst scoring of any region in the knee. Those who responded within 2 weeks were followed with regular phone calls and given the same response criteria. Those whose pain increased to within 20% of baseline pain were defined as “relapsers” and seen for another follow-up. Those who pain level did not return to this level after 6 months were considered to be “longer-term responders,” which comprised 20.1% of the patient population.
Investigators found greater MRI meniscal damage (ratio = 0.74), a higher KL maximal grade (ratio = 0.43) and increased JSN maximal score (ratio = 0.6) were linked with a reduced risk for being a longer-term responder to intra-articular steroid injection (IAIS). For longer-term responders, the likelihood of being a responder to IASI decreased from 38% to 12% when the overall JSN maximal scores increased from 0 to 3. In addition, the likelihood of being a responder to IASI decreased from 28% to 6% when the maximal meniscal score increased from 0 to 6. However, investigators found no significant drop for short-term responders, which comprised 73.4% of the patient population. In addition, they found no link between baseline synovitis and response. – by Will A. Offit
Disclosures: O’Neil reports no relevant financial disclosures. Please see the full study for a list of all other relevant disclosures.