The Relationship Between Patient Expectations And Outcomes Of Injections For Knee Osteoarthritis

Abstract

PURPOSE: Patient expectations have been shown to be related to outcomes after surgery. The relationship between expectations and outcomes after less invasive treatments, such as injections for knee osteoarthritis (OA), has not been studied. The objective of this prospective study was to assess the relationship between expectations and outcome of injections for knee OA. METHODS: We measured knee injection (intra-articular steroid or hyaluronic acid) expectations using a modified version of the Knee Replacement Expectations Scale (KRES) and Roland-Morris Disability Questionnaire. Patients were re-evaluated at 4 weeks post-injection for pain and disability outcomes. A multiple regression linear analysis was applied to model expectation entry scores; association between change in outcomes and expectation scores were studied through linear regression models, controlling for baseline scores as covariates. RESULTS: Forty-nine (n = 49) knee OA patients completed the study with improvement in knee weakness being the highest symptomatic improvement expected (mean score 4.8/5). Patients had the lowest expectations of pain relief and ability to walk (mean 1.3 and 1.1/5). Multivariate linear regression modeling did not show an association between demographic/clinical variables and global expectation scores. Injection treatment did significantly reduce pain (mean pain reduction 2.3, p < 0.001, and disability (p < 0.001)). Baseline expectation score had a low but significant association with change in pain and disability (NPRS R2 = 0.1, p = 0.056 and R2 = 0.14, p = 0.02). CONCLUSION: Knee injections improved pain and disability in this cohort of patients, and expectations before treatment had a small but significant association with patient reported outcomes. Studying a larger number of subjects and incorporating physical and psychological outcomes may further advance knowledge in this area.