ObjectiveCertain exercises could overload the osteoarthritic knee. We developed an exercise program from yoga postures with a minimal knee adduction moment for knee osteoarthritis. The purpose was to compare the effectiveness of this biomechanically-based yoga exercise (YE), with traditional exercise (TE), and a no-exercise attention-equivalent control (NE) for improving pain, self-reported physical function and mobility performance in women with knee osteoarthritis.DesignSingle-blind, three-arm randomized controlled trial.SettingCommunity in Southwestern Ontario, Canada.ParticipantsA convenience sample of 31 women with symptomatic knee osteoarthritis was recruited through rheumatology, orthopaedic and physiotherapy clinics, newspapers and word-of-mouth.InterventionsParticipants were stratified by disease severity and randomly allocated to one of three 12-week, supervised interventions. YE included biomechanically-based yoga exercises; TE included traditional leg strengthening on machines; and NE included meditation with no exercise. Participants were asked to attend three 1-hour group classes/sessions each week.MeasurementsPrimary outcomes were pain, self-reported physical function and mobility performance. Secondary outcomes were knee strength, depression, and health-related quality of life. All were assessed by a blinded assessor at baseline and immediately following the intervention.ResultsThe YE group demonstrated greater improvements in KOOS pain (mean difference of 22.9 [95% CI, 6.9 to 38.8; p = 0.003]), intermittent pain (mean difference of -19.6 [95% CI, -34.8 to -4.4; p = 0.009]) and self-reported physical function (mean difference of 17.2 [95% CI, 5.2 to 29.2; p = 0.003]) compared to NE. Improvements in these outcomes were similar between YE and TE. However, TE demonstrated a greater improvement in knee flexor strength compared to YE (mean difference of 0.1 [95% CI, 0.1 to 0.2]. Improvements from baseline to follow-up were present in quality of life score for YE and knee flexor strength for TE, while both also demonstrated improvements in mobility. No improvement in any outcome was present in NE.ConclusionsThe biomechanically-based yoga exercise program produced clinically meaningful improvements in pain, self-reported physical function and mobility in women with clinical knee OA compared to no exercise. While not statistically significant, improvements in these outcomes were larger than those elicited from the traditional exercise-based program. Though this may suggest that the yoga program may be more efficacious for knee OA, future research studying a larger sample is required.Trial registrationClinicalTrials.gov (NCT02370667)

People with knee osteoarthritis may benefit from exercise prescriptions that minimize knee loads in the frontal plane. The primary objective of this study was to determine whether a novel 12-week strengthening program designed to minimize exposure to the knee adduction moment (KAM) could improve symptoms and knee strength in women with symptomatic knee osteoarthritis. A secondary objective was to determine whether the program could improve mobility and fitness, and decrease peak KAM during gait. The tertiary objective was to evaluate the biomechanical characteristics of this yoga program. In particular, we compared the peak KAM during gait with that during yoga postures at baseline. We also compared lower limb normalized mean electromyography (EMG) amplitudes during yoga postures between baseline and follow-up. Primary measures included self-reported pain and physical function (Knee injury and Osteoarthritis Outcome Score) and knee strength (extensor and flexor torques). Secondary measures included mobility (six-minute walk, 30-second chair stand, stair climbing), fitness (submaximal cycle ergometer test), and clinical gait analysis using motion capture synchronized with electromyography and force measurement. Also, KAM and normalized mean EMG amplitudes were collected during yoga postures. Forty-five women over age 50 with symptomatic knee osteoarthritis, consistent with the American College of Rheumatology criteria, enrolled in our 12-week (3 sessions per week) program. Data from 38 were analyzed (six drop-outs; one lost to co-intervention). Participants experienced reduced pain (mean improvement 10.1–20.1 normalized to 100; p<0.001), increased knee extensor strength (mean improvement 0.01 Nm/kg; p = 0.004), and increased flexor strength (mean improvement 0.01 Nm/kg; p = 0.001) at follow-up compared to baseline. Participants improved mobility on the six-minute walk (mean improvement 37.7 m; p<0.001) and 30-second chair stand (mean improvement 1.3; p = 0.006) at follow-up compared to baseline. Fitness and peak KAM during gait were unchanged between baseline and follow-up. Average KAM during the yoga postures were lower than that of normal gait. Normalized mean EMG amplitudes during yoga postures were up to 31.0% of maximum but did not change between baseline and follow-up. In this cohort study, the yoga-based strengthening postures that elicit low KAMs improved knee symptoms and strength in women with knee OA following a 12 week program (3 sessions per week). The program also improved mobility, but did not improve fitness or reduce peak KAM during gait. The KAM during the yoga postures were lower than that of normal gait. Overall, the proposed program may be useful in improving pain, strength, and mobility in women with knee osteoarthritis. Clinical efficacy needs to be assessed using a randomized controlled trial design.Trial RegistrationClinicalTrials.gov NCT02146105

Muscle strengthening may be difficult to achieve in knee osteoarthritis (OA) due to pain. A large knee adduction moment (KAM), representing medial relative to lateral knee load, may also relate with pain during strengthening exercise. The objective of this study was to examine relationships between knee pain status and electromyography (EMG) amplitude of knee muscles during squat and lunge exercises. We also evaluated relationships between pain and KAM during these exercises. Forty-two women with symptomatic knee OA participated. Knee pain intensity and frequency were captured with two reliable and valid questionnaires. Motion analyses of squat and lunge exercises were completed. Total average EMG amplitude across five muscles of the lower limb and average KAM were calculated from the static portion of these exercises. Multiple regression analyses examined the relationships between pain and total average EMG amplitude; and pain and average KAM during squats and lunges. Pain improved the model for KAM from the trailing leg of a lunge. Pain did not improve any other model. Overall, pain may not be a useful indicator of EMG amplitude or KAM during exercise in knee OA.

Methods: This is a secondary data analysis from a community-based study of changes in regional and widespread pain (WSP) among women with chronic pain in Arizona, USA. Eligibility requirements for this analysis included: 1) female; 2) physician-confirmed diagnosis of osteoarthritis of the hip, knee or spine; and 3) onset of symptoms within the last 5 years or a current pain rating of >40 on a 0e100 scale in the past month. Exclusion criteria were: 1) autoimmune or other comorbid disorders causing widespread pain, inflammation, and fatigue (e.g., fibromyalgia, ankylosing spondylitis;) 2) pending litigation regarding the pain condition; and 3) use of daily corticosteroids. Participants (n ¼ 31) completed daily diaries and collected three saliva samples daily (10 AM, 4 PM, and 8 PM) for 7 days. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale assessed severity of OA-related pain. Multilevel regression analyses estimated associations between OA pain and diurnal cortisol levels, controlling for body mass index, medication use, time and day. To assess the diurnal pattern of cortisol, a model with an interaction term of time x WOMAC pain subscale score was fitted as a function of time. Then the association of cortisol levels with OA pain was assessed without the interaction term. A t-test using the median split of the WOMAC pain subscale (¼9) was conducted to assess the affect of severity of OA pain. Mediation analyses using the product of the coefficient approach, examined daily pain intensity, positive and negative affect, fatigue, ratings of stressfulness and enjoyment of daily events as potential mediators of the association between OA pain and cortisol. Results: The mean age was 57 years and average BMI 31kg/m2. Mean WOMAC pain subscale score was 8.8. A non-significant time x WOMAC interaction indicated that WOMAC pain scores did not alter the trajectory of cortisol levels throughout the day [Unstandardized ß 0.009 (À0.04, 0.06) p ¼ 0.724]. However, analyses revealed that there was a significant main effect of WOMAC pain subscale scores on cortisol levels [Unstandardized ß 0.083 (0.02, 0.15) p ¼0.009] representing a 0.083 ng/dl increase in cortisol per one unit increase in WOMAC pain score. Women with WOMAC pain scores > 9 had higher cortisol levels than those with scores <9 [mean (sd) 4.20 (0.94) versus 3.83 (0.91) p < 0.001 respectively]. No significant mediated effects were found (Table). Conclusions: In women with OA, disease-related pain is associated with elevated cortisol production, particularly when pain severity is greater. These results are the first to demonstrate that women with OA have altered HPA axis function secondary to disease-related pain. The absence of mediated effects questions the negative affective consequences of pain as a mechanism between pain and ill health. As there are several factors common to OA and cortisol dysfunction including links with obesity, metabolic syndrome and inflammation, future studies should explore alternative variables (e.g.,...

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