There are a number of validated unidimensional and multidimensional tools used to measure pain levels. The present widely used in clinical practice standard measure of pain relief in patients experiencing acute or chronic pain is a change in the numerical rating scale (NRS) score. NRS is a unidimensional scale that requires patients to mark their pain level from 0 (no pain) to 10 (worst pain). The NRS provides practitioners with pain levels pre-and-post treatment and is used as an indication of treatment efficacy. A significant limitation of the NRS, however, is that it provides an estimation of a single dimension of pain, pain intensity. Pain and pain relief, on the other hand, may have many dimensions including pain intensity, duration and magnitude of pain relief. Current multidimensional measures fail to capture duration of pain relief, thus there is a necessity to improve pain assessment tools. The integral of pain relief (IPR) is a novel two-dimensional measure of pain relief and duration of pain relief following treatment and may provide a more accurate depiction of post-treatment pain as well as intervention effectiveness. In this prospective cohort study, we intend to assess the validity of the IPR using validated measures of change in pain intensity (NRS), and the Patients' Global Impression of Change (PGIC) as well as The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in patients treated with corticosteroid injections for the osteoarthritis of knee joint.~The primary objectives of this study include:~Compare pre- and post-treatment scores of the i) IPR dimensions (post-treatment), ii) NRS (pre- and post-treatment), iii) PGIC (post-treatment), and iv) WOMAC (pre- and post-treatment) in patients with knee osteoarthritis treated with intra-articular corticosteroid injections.~Provide preliminary validation for the Integral of Pain Relief as a clinical assessment tool of post-treatment pain relief and treatment efficacy.~Secondary objectives of this study include:~Assess whether baseline patient characteristics such as pre-treatment pain intensity score, disease-associated pain duration, age, gender, co-morbidity with diabetes, symptoms of either depression or anxiety, or both, litigation status, occupation, and level of education are important predictors to responses on the four pain outcome measures.~Assess patients' impression of their usage of the daily pain diary versus providing the percentage and duration of pain relief at follow up time points.
The purpose of this study is to provide evidence for the empirical and clinical utility of a novel pain relief measure, the IPR, dimensions of which will be validated against the present gold standards for pain measurement.