Background Exercise is a core recommended treatment for knee osteoarthritis (OA), yet adherence declines, particularly following cessation of clinician supervision. Objective This study aims to evaluate whether a 24-week SMS intervention improves adherence to unsupervised home exercise in people with knee OA and obesity compared with no SMS. Methods A two-group superiority randomized controlled trial was performed in a community setting. Participants were people aged 50 years with knee OA and BMI ≥30 kg/m2 who had undertaken a 12-week physiotherapist-supervised exercise program as part of a preceding clinical trial. Both groups were asked to continue their home exercise program unsupervised three times per week for 24 weeks and were randomly allocated to a behavior change theory–informed, automated, semi-interactive SMS intervention addressing exercise barriers and facilitators or to control (no SMS). Primary outcomes were self-reported home exercise adherence at 24 weeks measured by the Exercise Adherence Rating Scale (EARS) Section B (0-24, higher number indicating greater adherence) and the number of days exercised in the past week (0-3). Secondary outcomes included self-rated adherence (numeric rating scale), knee pain, physical function, quality of life, global change, physical activity, self-efficacy, pain catastrophizing, and kinesiophobia. Results A total of 110 participants (56 SMS group and 54 no SMS) were enrolled and 99 (90.0%) completed both primary outcomes (48/56, 86% SMS group and 51/54, 94% no SMS). At 24 weeks, the SMS group reported higher EARS scores (mean 16.5, SD 6.5 vs mean 13.3, SD 7.0; mean difference 3.1, 95% CI 0.8-5.5; P=.01) and more days exercised in the past week (mean 1.8, SD 1.2 vs mean 1.3, SD 1.2; mean difference 0.6, 95% CI 0.2-1.0; P=.01) than the control group. There was no evidence of between-group differences in secondary outcomes. Conclusions An SMS program increased self-reported adherence to unsupervised home exercise in people with knee OA and obesity, although this did not translate into improved clinical outcomes. Trial Registration Australian New Zealand Clinical Trials Registry 12617001243303; https://tinyurl.com/y2ud7on5 International Registered Report Identifier (IRRID) RR2-10.1186/s12891-019-2801-z

Objective: Different exercise types may yield different outcomes in osteoarthritis (OA) subgroups. The objective was to directly compare effectiveness of two exercise programs for people with medial knee OA and co-morbid obesity. Design: We performed a participant-and assessor-blinded randomized controlled trial. 128 people !50 years with medial knee OA and body mass index !30 kg/m 2 were recruited from the community. Interventions were home-based non-weight bearing (NWB) quadriceps strengthening or weight bearing (WB) functional exercise for 12 weeks. Primary outcomes were change in overall knee pain (numeric rating scale, range 0e10) and difficulty with physical function (Western Ontario and McMaster Universities Osteoarthritis Index, 0e68) over 12 weeks. Secondary outcomes included other pain measures, physical function, quality-of-life, global changes, physical performance, and lower-limb muscle strength. Results: 123 (96%) participants were retained. There was no evidence of a between-group difference in change in pain (mean difference 0.73 units (95% confidence intervals (0.05,1.50)) or function (2.80 units (À1.17,6.76)), with both groups reporting improvements. For secondary outcomes, the WB group had greater improvement in quality-of-life (À0.043 units (À0.085,-0.001)) and more participants reporting global improvement (overall: relative risk 1.40 (0.98,2.01); pain 1.47 (0.97,2.24); function 1.43 (1.04,1.98). Although adverse events were minor, more NWB group participants reported !1 adverse event (26/66 (39%) vs 14/62 (23%), p ¼ 0.04). Conclusions: Both exercise types similarly improved primary outcomes of pain and function and can be recommended for people with knee OA and obesity. WB exercise may be preferred given fewer adverse events and potential additional benefits on some secondary outcomes.

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Background Knee osteoarthritis (OA) is a highly prevalent condition. People with knee OA often have other co-morbidities such as obesity. Exercise is advocated in all clinical guidelines for the management of knee OA. It is often undertaken as a home-based program, initially prescribed by a physiotherapist or other qualified health care provider. However, adherence to home-based exercise is often poor, limiting its ability to meaningfully change clinical symptoms of pain and/or physical function. While the efficacy of short message services (SMS) to promote adherence to a range of health behaviours has been demonstrated, its ability to promote home exercise adherence in people with knee OA has not been specifically evaluated. Hence, this trial is investigating whether the addition of an SMS intervention to support adherence to prescribed home-based exercise is more effective than no SMS on self-reported measures of exercise adherence. Methods We are conducting a two-arm parallel-design, assessor-and participant-blinded randomised controlled trial (ADHERE) in people with knee OA and obesity. The trial is enrolling participants exiting from another randomised controlled trial, the TARGET trial, where participants are prescribed a 12-week home-based exercise program (either weight bearing functional exercise or non-weight bearing quadriceps strengthening exercise) for their knee by a physiotherapist and seen five times over the 12 weeks for monitoring and supervision. Following completion of outcome measures for the TARGET trial, participants are immediately enrolled into the ADHERE trial. Participants are asked to continue their prescribed home exercise program unsupervised three times a week for 24-weeks and are randomly allocated to receive a behaviour change theory-informed SMS intervention to support home exercise adherence or to have no SMS intervention. Outcomes are measured at baseline and 24-weeks. Primary outcomes are self-reported adherence measures. Secondary outcomes include self-reported measures of knee pain, physical function, quality-of-life, physical activity, self-efficacy, kinesiophobia, pain catastrophising, participant-perceived global change and an additional adherence measure. Discussion Findings will provide new information into the potential of SMS to improve longer-term exercise adherence and ultimately enhance exercise outcomes in knee OA. Trial registration Prospectively registered with the Australian New Zealand Clinical Trials Registry. Reference: ACTRN12617001243303 Date/version: August 2019/two

To explore challenges associated with implementing a home-based strengthening exercise program for individuals with knee osteoarthritis and comorbid obesity.Methods. This is a qualitative study embedded within a randomized controlled trial comparing 2 home-based strengthening programs (weight-bearing functional exercise versus non-weight-bearing quadriceps strengthening exercise) for individuals with knee osteoarthritis and comorbid obesity. Patients in both exercise programs attended 5 consultations with a physical therapist and undertook a home-based exercise program for 12 weeks. After trial completion, semistructured individual telephone interviews were conducted with 22 patients and all 7 physical therapists who delivered trial interventions. Interviews were recorded, transcribed verbatim, and thematically analyzed using an inductive approach.Results. Three themes arose: 1) psychological challenges (false assumptions about exercise; fear of pain; disliking exercise; mental effort of the weight-bearing functional program; underestimating capability); 2) physical challenges (complexity of the weight-bearing functional program; cuff weights and straight leg raise being problematic in nonweight-bearing quadriceps program; other health conditions); and 3) overcoming challenges (incentives to exercise; accountability; education and reassurance; tailoring the exercise program).Conclusion. Patients and physical therapists experienced numerous psychological and physical challenges to exercise, including a fear of pain, having false assumptions about exercise, difficulties with exercise performance, application of cuff weights, and adverse impacts of other health conditions.