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Background Prescription of analgesics is complex in patients with knee OA and severe pain. We developed a protocol for the standardized prescription of analgesics based on the World Health Organization analgesic ladder (1) and the Beating osteoARTritis (BART) strategy for stepped care in hip and knee OA (2). Objectives The aim of this study was to evaluate the feasibility and outcome of the analgesic protocol. Methods Forty-nine patients with knee OA and severe knee pain (NRS≥7; range 0-10) were included. Analgesics were prescribed following an incremental protocol (Figure 1) for a period of six weeks. Pain intensity was evaluated every two weeks. When there was insufficient pain reduction (NRS-pain>5), a consultation at the rheumatologist was planned to offer an analgesic of the next step. Analgesics of the next step were added to analgesics of the previous step(s). Analgesic use was recorded. Knee pain (NRS-pain) and activity limitations (WOMAC-PF) were measured. Data were collected at baseline and after six weeks. Subsequently, patients started with exercise therapy. Results At baseline 84% of the patients used analgesics. Of all patients, 77% used acetaminophen, 36% used NSAIDs and 16% used weak opioids. At baseline, analgesics were used irregularly and at an suboptimal dose. Analgesic use after six weeks is described in Figure 1. The maximal daily dosage was used in 93% of the patients that used acetaminophen, in 66% of the patients that used NSAIDs, and in 44% of the patients that used weak opioids. Combinations of analgesics were common. No serious adverse events occurred. In 39% of the patients NRS-pain was ≤5 after six weeks. Despite NRS-pain>5, a further step in the analgesic protocol was not accepted by the patient (n=14) or not prescribed by the rheumatologist (n=13), the latter mostly due to contra-indications or side effects. Statistically significant and clinically relevant mean improvements from baseline were 19% (p Conclusions After six weeks, patients used analgesics regularly and often at a preferential dose. Prescription of analgesics following an incremental protocol reduces pain and activity limitations in patients with knee OA and severe pain. References World Health Organization. Cancer pain relief: with a guide to opioid availability. Available at: http://whqlibdoc.who.int/publications/9241544821.pdf (accessed 14 January 2014). Smink AJ, et al. Clin Rheumatol 2011;30:1623-9. Disclosure of Interest None declared

Background Severe pain in patients with knee OA hampers the ability to exercise. A protocol for the optimization of analgesics in combination with exercise therapy was developed. The purpose of this protocol is to reduce pain and thereby allowing the patient to participate in exercise therapy. Objectives The objective of the present study was to evaluate the feasibility and outcome of the protocol. Methods Forty-nine patients with knee OA and severe knee pain (NRS-pain≥7, range 0-10) were included in this study. Analgesics were prescribed following an incremental protocol. The incremental steps were (1) acetaminophen, (2) NSAIDs, (3) weak opioids and (4) intra-articular steroid injections. After six weeks of analgesic use a supervised exercise therapy program for 12 weeks was added, consisting of muscle strengthening exercises and training of daily activities. Knee pain was assessed with NRS-pain and activity limitations were assessed with WOMAC-PF. Data were collected at baseline, after six weeks, and after 18 weeks. Results In intention-to-treat analyses statistically significant improvements in pain and activity limitations were found after six weeks of analgesic use and after the complete intervention. Mean improvements from baseline were 30% (p Conclusions The combined intervention of analgesics and exercise therapy allows most patients with knee osteoarthritis and severe pain to participate in exercise therapy, leading to reduction of pain and activity limitations. These promising results need to be confirmed in a randomized controlled trial. Disclosure of Interest None declared

Background Osteoarthritis (OA) of the knee is a leading cause of activity limitations (e.g. stair-climbing, walking) in Western countries (1), and an important physical determinant of activity limitations is muscle strength (2;3). Recent evidence points out that proprioception and varus-valgus laxity moderate (i.e. alter the strength of) the association between muscle strength and activity limitations (2;3). In early OA the moderating roles of proprioception and laxity have not yet been examined. Objectives To establish whether proprioception and varus-valgus laxity moderate the association between muscle strength and activity limitations in patients with early symptomatic knee OA. Methods A cross-sectional study was conducted in a sample of 151 participants with early symptomatic knee OA from the Cohort Hip and Cohort Knee (CHECK) study. Regression analyses were performed to establish the associations between muscle strength, proprioception (knee joint motion detection threshold in the anterior-posterior direction), varus-valgus laxity and activity limitations (self-reported and performance based). Interaction terms were used to establish whether proprioception and laxity moderated the association between muscle strength and activity limitations. Results Proprioception moderated the association between muscle strength and activity limitations: the negative association between muscle strength and activity limitations was stronger in participants with poor proprioception than in participants with accurate proprioception (performance based activity limitations, p=0.02; self-reported activity limitations, p=0.08). Varus-valgus laxity did not moderate the association between muscle strength and activity limitations: the interaction between muscle strength and varus-valgus laxity was not significantly associated with activity limitations. Conclusions The results of the present study support the theory that in the absence of adequate motor control through poor proprioceptive input, lower muscle strength affects a patient’s level of activities to a greater degree than in the presence of adequate motor control. References Michaud CM, McKenna MT, Begg S, Tomijima N, Majmudar M, Bulzacchelli MT et al. The burden of disease and injury in the United States 1996. Popul Health Metr 2006; 4:11. van der Esch M, Steultjens M, Knol DL, Dinant H, Dekker J. Joint laxity and the relationship between muscle strength and functional ability in patients with osteoarthritis of the knee. Arthritis Rheum 2006; 55(6):953-959. van der Esch M, Steultjens M, Harlaar J, Knol D, Lems W, Dekker J. Joint proprioception, muscle strength, and functional ability in patients with osteoarthritis of the knee. Arthritis Rheum 2007; 57(5):787-793. Disclosure of Interest None Declared

Background Although biomechanical factors of the knee joint like muscle strength, proprioceptive accuracy and laxity play an important role in knee osteoarthritis (OA), only limited evidence exists on associations with specific tissue abnormalities. Furthermore, findings from physical examination have never been studied in relation to tissue abnormalities of the knee joint. Objectives To explore associations between tissue abnormalities assessed by conventional radiography and high resolution MRI, biomechanical factors and physical examination findings in patients with knee OA. Methods Explorative cross-sectional study in 105 patients with knee OA. Knees were imaged using radiography and 3.0 Tesla MRI. Multivariable regression analyses were used to explore associations between tissue abnormalities, visualised by radiography or MRI, biomechanical factors (quadriceps and hamstrings muscle strength, proprioceptive accuracy and varus-valgus laxity) and physical examination findings (bony tenderness, crepitus, bony enlargement and palpable warmth). Results MRI based synovitis, MRI based cartilage loss and radiographic based joint space narrowing were found to be associated with quadriceps weakness. Radiographic features (joint space narrowing and osteophyte formation) were related to varus-valgus laxity. Multiple tissue abnormalities, but only those detected by MRI, were associated with physical examination findings (crepitus and palpable warmth). Neither MRI features nor radiographic features were found to be associated with hamstrings muscle strength, proprioceptive accuracy, bony tenderness and bony enlargement. Conclusions In conclusion, a discordance between tissue abnormalities, biomechanical factors and physical examination findings in knee OA was observed, for both conventional radiography and high resolution MRI. Relevant new findings include a highly significant association between MRI based synovitis and quadriceps weakness and a superiority of MRI over conventional radiography in association with physical examination findings. Disclosure of Interest None Declared

Background Exercise therapy is a cornerstone treatment in knee OA, but effects on pain and activity limitations are only moderate at best. Objectives To test our hypothesis that an exercise program, initially focusing on knee joint stabilization and subsequently on muscle strength and performance of daily activities is more effective in reducing activity limitations in patients with knee osteoarthritis (OA) and instability of the knee joint, compared to an exercise program focusing on muscle strength and performance of daily activities only. Methods A single-blind, randomized, controlled trial involving 159 knee OA patients with self-reported and/or biomechanically assessed knee instability, randomly assigned to two treatment groups. Both groups received a supervised exercise program for 12 weeks, consisting of muscle strengthening exercises and training of daily activities, but only in the experimental group exercises initial knee stabilization training was provided. Outcome measures included activity limitations (WOMAC physical function, primary outcome), pain, global perceived effect and knee stability. Results Both treatment groups demonstrated large (~20-40%) and clinically relevant reductions in activity limitations, pain and knee instability, which were sustained six months post treatment. No differences in effectiveness between experimental and control treatment were found on WOMAC physical function (B (95% CI) = -0.01 (-2.58-2.57)) or secondary outcome measures, except for a higher global perceived effect in the experimental group (p=.04). Subgroupanalyses revealed a significant interaction between baseline upper leg muscles strength and group effect on WOMAC, physical function (p=.02). Conclusions Both exercise programs were highly effective in reducing activity limitations and pain and restoring knee stability. Addition of specific knee joint stabilization training does not seem to be necesarry in the targeted group of knee OA patients suffering from knee instability, although subgroupanalyses suggest that those persons that have stronger upper leg muscles at baseline may benefit more from an exercise program that additionally focuses on knee joint stabilization. Disclosure of Interest None Declared