Background. This article reviews four commonly used approaches to assess patient responsiveness to a treatment or therapy [Return To Normal (RTN), Minimal Important Difference (MID), Minimal Clinically Important Difference (MCID), OMERACT-OARSI (OO)], and demonstrates how each of the methods can be formulated in a multi-level modelling (MLM) framework. Methods. Data from the Arthroplasty Pain Experience (APEX) cohort study was used. Patients undergoing total hip and knee replacement completed the Intermittent and Constant Osteoarthritis Pain (ICOAP) questionnaire prior to surgery and then at 3, 6 and 12 months after surgery. We compare baseline scores, change scores, and proportion of individuals defined as “responders” using traditional and multi-level model (MLM) approaches to patient responsiveness. Results. Using existing approaches, baseline and change scores are underestimated, and the variance of baseline and change scores overestimated in comparison to MLM approaches. MLM increases the proportion of individuals defined as responding in RTN, MID, and OO criteria compared to existing approaches. Using MLM with the MCID criteria reduces the number of individuals identified as responders. Conclusion. MLM improves the estimation of the standard deviation of baseline and change scores by explicitly incorporating measurement error into the model, and avoiding regression to the mean when making individual predictions. Using refined definitions of responsiveness may lead to a reduction in misclassification when attempting to predict who does and does not respond to an intervention, and clarifies the similarities between existing methods. Approvals. The APEX trials were registered as an International Standardised Randomised Controlled Trial (96095682), approved by Southampton and South West Hampshire Research Ethics Committee (09/H0504/94) and all participants provided informed written consent

Background. Chronic pain after joint replacement is common, affecting approximately 10% of patients after total hip replacement (THR) and 20% of patients after total knee replacement (TKR). Heightened generalised sensitivity to nociceptive input could be a risk factor for the development of this pain. The primary aim of this study was to investigate whether preoperative widespread pain sensitivity was associated with chronic pain after joint replacement. Methods. Data were analysed from 254 patients receiving THR and 239 patients receiving. TKR. Pain was assessed preoperatively and at 12 months after surgery using the Western Ontario and McMaster Universities Osteoarthritis Pain Scale. Preoperative widespread pain sensitivity was assessed through measurement of pressure pain thresholds (PPTs) at the forearm using an algometer. Statistical analysis was conducted using linear regression and linear mixed models, and adjustments were made for confounding variables. Results. In both the THR and TKR cohort, lower PPTs (heightened widespread pain. sensitivity) were significantly associated with higher preoperative pain severity. Lower PPTs were also significantly associated with higher pain severity at 12 months after surgery in the THR cohort. However, PPTs were not associated with the change in pain severity from preoperative to 12 months postoperative in either the TKR or THR cohort. Conclusions. These findings suggest that although preoperative widespread pressure pain sensitivity is associated with pain severity before and after joint replacement, it is not a predictor of the amount of pain relief that patients gain from joint replacement surgery, independent of preoperative pain severity. Level of Evidence. 2. Approvals. The APEX trials were registered as an International Standardised Randomised Controlled Trial (96095682), approved by Southampton and South West Hampshire Research Ethics Committee(09/H0504/94) and all participants provided informed written consent

Background. Osteoarthritis (OA) pain treatment has limitations in terms of serious adverse effects and low efficacy. We aimed to evaluate efficacy and safety of naproxen sodium/codeine phosphate combination in these patients. Methods. In this prospective, randomised, double blind, placebo controlled clinical trial, 135 patients with osteoarthritis, who were 40–65 years; applied to our institution's orthopaedics outpatient clinic; had grade 1, 2, or 3 primary osteoarthritis diagnosed in last 1 year; and had Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score≥40, and Visual Analogue Scale score≥40, were enrolled. Subjects were randomised (1:1) to placebo (n= 67) or combination (n= 68) arms, in which 550 mg naproxen sodium/30mg codeine phosphate was given orally twice a day for 7 days. Rescue medicine was 500 mg paracetamol (max= 6 tablets/day). Demographic characteristics, medical history, adverse events, VAS and WOMAC scores were collected in study visits performed within 10 days. The study was approved by local institutional ethics committee and written informed consents were obtained from all participants. Results. Patients were evenly matched in both arms. The mean age was 52.3±6.6 years (89.7% female). WOMAC and VAS scores decreased significantly within each group (p<0.001 for all). For the study group (n=43) the mean (+ SD) and median (min-max) VAS Score was −29.8 (+21.0) and −30 (−70−0), respectively. In contrast, for the control group (n=36) the mean and median (min-max) VAS Score was −16.1 (+24.4) and −12.5 (−65−40), respectively. WOMAC score was decreased more in combination group (p= 0.044). Changes in VAS scores between visits were significantly different (more in combination receivers) between groups (p= 0.018). Ratio of patients requiring no rescue medicine was higher among combination receivers than controls (64.8% vs. 35.2%, respectively). Most common adverse events were constipation, dyspepsia, and somnolence; no fatality was encountered. Conclusions. Naproxen sodium/codeine phosphate combination is effective and safe in osteoarthritis patients. Level of Evidence. Level 1

Objectives

In this study, we compared the pain behaviour and osteoarthritis (OA) progression between anterior cruciate ligament transection (ACLT) and osteochondral injury in surgically-induced OA rat models.