Poster 235: The Role of Symptom Duration in Shaping Outcome Expectations of Patients Initiating Nonoperative Treatment for Meniscal Tear

OBJECTIVES: Nonoperative treatment represents a safe, guideline-based approach for meniscal injuries, but it is unclear why or how it works. It is often assumed that nonoperative treatments (e.g., physical therapy) exerts their effects (e.g., symptom relief) via technical procedures (e.g., exercise regimen) but a variety of nonspecific factors (e.g., expectations for treatment and its credibility) commonly part of any treatment (e.g., physical therapy, surgery, pharmacotherapy, behavior therapy, etc.) also influence outcomes. In general, patients who believe a treatment is believable, convincing or logical (credibility) and will be useful for relieving the symptoms for which they seek treatment (outcome expectancy) are more likely to achieve clinically meaningful change than patients with negative expectancies. Patients with low treatment credibility and outcome expectancies not only may be less likely to achieve treatment goals but may also be at greater risk for dropout. Despite evidence supporting their role in pharmacotherapy and behavior therapy, little research has been carried out in understanding the role of treatment credibility and expectancies in shaping successful treatment of rehabilitative treatments for meniscal tears. Utilizing baseline data collected from the Treatment of Meniscal Tears in Osteoarthritis trial we sought to assess treatment credibility and treatment expectancies for improvement of knee symptoms and their clinical and sociodemographic correlates. Given the strong influences of cognitive processes on pain as it persists, our a priori hypothesis was that expectations for symptom improvement would be greater for patients with shorter duration of knee symptoms than those with persistent knee symptoms. METHODS: Participants included 126 patients (58 years old (range: 45-75), 51% women, 91% white) who rated credibility of treatment to which they were assigned and expectations for symptom improvement using a modified version of the Credibility Expectancy Questionnaire (CEQ-Meniscus Treatment) based on a psychometrically validated measure two weeks post randomization. Ratings were obtained after rationale for treatment was provided but before the full scope of therapy was implemented so as not to contaminate them by treatment response. Credibility ratings were calculated by taking the mean of the first three items of the CEQ to create an overall credibility rating (9-point scale). We adopted the practice of measuring expectancy by using the CEQ-MT that asks patients to rate, on a 0 to 100% scale (in 10-point increments), “By the end of treatment, how much improvement in knee symptoms do you think will occur?” We also examined expectancy items from the Musculoskeletal Outcomes Data Evaluation and Management Scale (MODEMS) that assess pretreatment expectations for relief of knee symptoms and their impact on activities of living (e.g., housework, sleep). Each item had a possible range of 1 (not likely) to 5 (extremely likely). Overall MODEMS symptom expectancy scores were calculated by taking the mean of the first 5 items. RESULTS: Ninety-three percent of the participants completed the survey. On the CEQ-MT, average treatment credibility (Mean = 6.5) and expectancy ratings (Mean = 70%) were high. Similarly, the MODEMS expectancies were high, on average (Mean = 4.0). Expectancies for improvement and the extent to which treatment was deemed credible moderately correlated with each other (r range 0.30 - 0.52, p<.05). Credibility but not outcome expectancy varied by race, with participants identifying as white reporting higher treatment average credibility scores, 5.2 and 6.5, p=.03, respectively. Credibility scores did not vary by knee pain duration. Patients experiencing knee pain for 0-2 months (i.e., acute) expected, on average, that a 76% improvement would occur by the end of therapy, compared with 64% for patients experiencing pain persisting 3 months and longer (i.e., chronic), p=.002. Similarly, mean MODEMS expectancy scores varied by pain duration, with acute patients reporting stronger expectancies of symptom reduction than their chronic counterparts (4.2 and 3.8, p=.002). CONCLUSIONS: To our knowledge, this is the first study that has sought to assess systematically baseline levels of perceived treatment credibility and expectations for improvement in a cohort of patient undergoing nonoperative therapy for meniscus tears. Our primary findings are treatment credibility varied by race and that treatment outcome expectancies differed significantly by pain duration (acute vs chronic). Understanding beliefs patients have about treatment is a clinically relevant research focus because they are among the most powerful “common factors” (i.e., those that are not specific to any one treatment but are shared across all) that can influence treatment outcomes above and beyond technical components of a therapy. Their role in contributing to the management of meniscus tear is unknown. Data from this study suggest that common factors such as treatment expectancy may be particularly operative in patients whose knee symptoms following meniscus injuries persists beyond the acute phase.