The effect of body weight on progression of knee osteoarthritis is dependent on alignment. Arthritis Rheum

Boston University Clinical Epidemiology Research and Training, Boston, Massachusetts, USA.
Arthritis & Rheumatology (Impact Factor: 7.87). 12/2004; 50(12):3904-9. DOI: 10.1002/art.20726
Source: PubMed

ABSTRACT Whereas obesity increases overall loading of the knee, limb malalignment concentrates that loading on a focal area, to the level at which cartilage damage may occur. This study evaluated whether the effect of body weight on progression of knee osteoarthritis (OA) differs depending on the degree of limb malalignment.
The study population comprised 228 veterans and community recruits with symptomatic knee OA (pain on most days and radiographic disease) who volunteered to participate in a natural history study and from whom baseline radiographs were obtained to assess alignment; 227 (99.6%) completed a 30-month followup. Of 403 knees assessed at baseline, 394 (97.8%) were followed up. Participants' body mass index (BMI) was assessed at each examination. The main outcome measure was progression of knee OA, defined as narrowing of the tibiofemoral joint space by 1 grade (semiquantitative scale 0-3) on radiographs of the fluoroscopically positioned knee. The association between BMI and the risk of knee OA progression was assessed after adjusting for age, sex, and limb alignment, using logistic regression and generalized estimating equations.
Of 394 knees, 90 (22.8%) showed disease progression, and limb alignment was strongly associated with progression risk. The risk of progression increased with increasing weight (for each 2-unit increase in BMI, odds ratio [OR] for progression 1.08, 95% confidence interval [95% CI] 1.00-1.16). However, among those knees with neutral alignment (0-2 degrees ), increases in BMI had no effect on risk of progression (OR 1.00), and in those with severe malalignment (> or =7 degrees ), the effect was similarly null (OR 0.93). The effect of BMI on progression was limited to knees in which there was moderate malalignment (OR per 2-unit increase in BMI 1.23, 95% CI 1.05-1.45).
Although elevated BMI increases the risk of knee OA progression, the effect of BMI is limited to knees in which moderate malalignment exists, presumably because of the combined focus of load from malalignment and the excess load from increased weight. This has implications for clinical recommendations and for trials testing weight loss in those with knee OA.

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    • "Obesity accelerates the progression of knee osteoarthritis in the presence of moderate knee malalignment [5] [6] [7] [8] [9]. Based on a systematic review of 25 studies, Butterworth and colleagues noted an association between higher body mass index (BMI) and higher rates of chronic heel pain, non-specific foot pain, and tendonitis [10]. "
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    ABSTRACT: Objective To investigate the effects of weight reduction on foot structure, gait, and dynamic plantar loading in obese adults. Design In a 3-month randomized-controlled trial, participants were randomized to receive either a weight loss intervention based on portion-controlled meals or a delayed-treatment control. Participants 41 adults (32 F, 9 M) with a mean + SD age of 56.2 + 4.7 years and a BMI of 35.9 + 4.2 kg/m2. Measurements Arch Height Index (AHI), Malleolar Valgus Index (MVI), spatial and temporal gait parameters, plantar peak pressure (PP) and weight were measured at baseline, 3, and 6 months. Results The intervention group experienced significantly greater weight loss than did the control group (5.9 ± 4.0 kg versus 1.9 ± 3.2 kg, p = 0.001) after 3 months. There were no differences between the groups in anatomical foot structure or gait. However, the treatment group showed a significantly reduced PP than the control group beneath the lateral arch and the metatarsals 4 (all P values < .05) at 3 months. The change in PP correlated significantly with the change in weight at the metatarsal 2 (r = 0.57, p = 0.0219), metatarsal 3 (r = 0.56, p = 0.0064) and the medial arch (r = 0.26, p < 0.0001) at 6 months. Conclusion This was the first RCT designed to assess the effects of weight loss on foot structure, gait, and plantar loading in obese adults. Even a modest weight loss significantly reduced the dynamic plantar loading in obese adults. However, weight loss appeared to have no effects on foot structure and gait.
    Gait & Posture 09/2014; 41(1). DOI:10.1016/j.gaitpost.2014.08.013 · 2.30 Impact Factor
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    • "In persons vulnerable to the development of knee OA, local mechanical factors, such as abnormal joint congruity, malalignment (varus or valgus deformity), muscle weakness, or alterations in the structural integrity of the joint environment (such as meniscal damage or ligament rupture), facilitate the progression of OA. Loading can also be affected by obesity and joint injury (either acutely as in a sporting injury or after repetitive overuse, such as occupational exposure), both of which can increase the likelihood of development or progression of OA [6]. Lower extremity muscle weakness may play an important role in knee OA. "
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    ABSTRACT: Objective: To evaluate the effectiveness of Electromyographic-biofeedback as an add-on therapy with isometric exercise on quadriceps strengthening in patient with osteoarthritis of knee. Design: Randomized case controlled design. Setting: Outpatient physiotherapy department, Majeedia Hospital, New Delhi, India. Participants: Thirty three (10 men and 23 women) patients with osteoarthritis of knee participated in the study. Patients were randomly placed into two groups: a biofeedback group (n�17) and a control group (n�16). The criteria for inclusion were: radiological evidence of primary osteoarthritis with grade 2 on the Kellgren Lawrence scale; age between 40-65 years; unilateral or bilateral involvement. Intervention: The biofeedback group received electromyographic-biofeedback guided isometric exercise program for 5 days a week for 5 weeks, whereas the control group received an exercise program only. Main Outcome measure: The isometric strength of quadriceps femoris was used as the outcome measure of this study. Measurements were taken at baseline (before treatment), at the end of 2nd week, 3rd week and 5th week using electronic strain gauge device. Results: At the end of the 2nd week, the between-group difference in quadriceps muscle strength remained non-significant (p�0.33, 95% CI�2.12 to 0.73), but became statistically significant at the end of the 3rd week (p�0.047, 95% CI�2.93 to 0.01). The difference in quadriceps muscle strength between the two groups remained significant at the end of the treatment period (5th week) (p�0.004, 95% CI�3.70 to .76). Conclusion: The addition of electromyographic biofeedback to a 5-week isometric exercise program appeared to increase quadriceps muscle strength, compared to the exercise program alone for people with knee OA. The finding, however, should be interpreted with caution due to limitations of the study design Key Words: Biofeedback; Exercise; Arthritis; Arthropathy; Strength; Rehabilitation.
    Archives of Physical Medicine and Rehabilitation 10/2011; 92(10):1733. · 2.44 Impact Factor
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    • "Local mechanical factors mediate the impact of more systemic factors such as obesity on the knee [Felson et al. 2004]. Obesity is the single most important risk factor for development of severe OA of the knee and more so than other potentially damaging factors including heredity "
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    ABSTRACT: The pathogenesis of osteoarthritis (OA) appears to be the result of a complex interplay between mechanical, cellular, and biochemical forces. Obesity is the strongest risk factor for disease onset and mechanical factors dominate the risk for disease progression. This narrative review focuses on the influence of biomechanics and obesity on the etiology of OA and its symptomatic presentation. We need to revisit the way we currently manage the disease and focus on the modifiable, primarily through nonpharmacologic intervention. Greater therapeutic attention to the important role of mechanical factors and obesity in OA etiopathogenesis is required if we are to find ways of reducing the public health impact of this condition.
    Therapeutic advances in musculoskeletal disease 02/2009; 1(1):35-47. DOI:10.1177/1759720X09342132
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