Both osteoarthritis (OA) and metabolic syndrome (MetS) are associated with obesity and it may therefore not be unexpected to see increased prevalence of OA in patients with MetS and vice versa.

On the other hand, given the negative impact of OA on physical activity levels, it may also not be unreasonable to assume that individuals with OA may be more likely to present with weight gain and features of the MetS.

Finally, both OA and obesity have been associated with low levels of systemic inflammation, another factor that may promote metabolic abnormalities in these patients.

But how close is the relationship between OA and MetS in the general population?

This question was recently addressed by Rajitkanok Punepatom and colleagues from Chadds Ford, PA, in a paper just published in Postgraduate Medicine.

This study examined whether having OA predicts the presence of MetS in the National Health and Nutrition Examination Survey (NHANES) III, a representative sample of the general US population. The data set included 7714 subjects, of whom 975 subjects had OA.

Metabolic syndrome was present in 59% of the OA population and 23% of the population without OA with each of the 5 cardiovascular risk factors that comprise MetS being more prevalent in the OA population: hypertension (75% vs 38%), abdominal obesity (63% vs 38%), hyperglycemia (30% vs 13%), elevated triglycerides (47% vs 32%), and low high-density lipoprotein cholesterol (44% vs 38%).

The association between OA and MetS was strongest in younger subjects, where having OA at age 44 years was associated with an over 5-fold increased risk of MetS - a relationship that remained significant despite adjustment for body weight and other confounders.

This, not entirely unexpected association between OA and MetS, particularly in younger individuals, has a number of important clinical implications:

1) Cardiovascular risk factors should be routinely assessed and addressed in younger individuals presenting with OA.

2) Vice versa, assessment of joint health should perhaps be a routine part of assessment in younger patients presenting with signs of MetS.

3) It is likely that the common presentation of OA in patients presenting with MetS can be a significant barrier to increasing physical activity and weight management and therefore likely needs to be specifically addressed with appropriate physical and medical treatments.

AMS
Ottawa, Ontario

The musculoskeletal consequences of overweight and obesity are perhaps by far the most disabling and costly sequelae of excess weight. Although they may be less likely to kill you than heart disease or stroke (also consequences of obesity), obesity related pains in your muscle, bones and joints can reduce your quality of life to a level where having a heart attack may seem like taking the easy way out.

So what is the best conservative treatment for weight-related knee pain?

This question was addressed now in a randomised controlled trial published last month in the British Medical Journal. Specifically, Claire Jenkinson and colleagues from the University of Nottingham, UK examined the effects of dietary intervention and quadriceps strengthening exercises on pain and function in overweight people with knee pain.

The study was performed in five general practices in Nottingham and involved 389 men and women aged 45 and over with a body mass index equal or greater than 28.0 and self reported knee pain.

Participants were randomised to dietary intervention plus quadriceps strengthening exercises; dietary intervention alone; quadriceps strengthening exercises alone; or and advice leaflet only (control group).

Dietary intervention consisted of individualised healthy eating advice that would reduce normal intake by 600 kcal a day. Interventions were delivered at home visits over a two year period.

In the 289 (74%) participants who completed the trial, patients in the knee exercise groups reported greater reduction in knee pain than in the non-exercise groups at 24 months, although the effect size was moderate (number needed to treat for a 30% improvement in knee pain was 9).

As expected the dietary intervention group lost some weight (around 3 Kg), but this degree of weight loss did not have any meaningful effect on knee pain or function but was associated with a reduction in depression.

The authors conclude that a home based, self managed programme of simple knee strengthening exercises over a two year period can significantly reduce knee pain and improve knee function in overweight and obese people with knee pain.

Although a moderate sustained weight loss is achievable with dietary intervention and is associated with reduced depression, it is not enough to influence pain or function.

As knee pain is a common problem in patients presenting with excess weight, which if not addressed, will ultimately result in immobility and increasing weight gain, exercise prescriptions should be routinely implemented in patients presenting with this problem.

AMS
Edmonton, Alberta

Excess weight markedly increases the risk for a wide range of health problems including diabetes, heart disease, gall bladder stones, back pain, hip and knee problems and certain cancers. It is therefore reasonable to hypothesize that obesity is associated with increased need for hospitalization. This question is important because hospitalization accounts for a substantial proportion of health care costs.

Han and colleagues from the University of North Carolina, Chapel Hill, NC examined the relationship between obesity and hospitalization in the around 15,000 participants of the ARIC (Atherosclerosis Risk in Communities) Study, prospectively followed for 13 years - the results were published online in the International Journal of Obesity last week.

The study examined associations between weight status and all-cause and cause-specific hospitalizations (for cardiovascular and a few selected non-cardiovascular conditions). Analyses were adjusted for numerous factors including race, gender, age, physical activity, education level, smoking status, alcoholic beverage consumption and health insurance at baseline.

The average number of all-cause hospitalizations increased from 1316 per 1000 in normal weight individuals to 1543 in overweight and 2025 in obese participants. While normal weight women had significantly fewer hospitalizations than normal weight men (1173 versus 1515 per 1000), but the increase associated with being obese on the number of all-cause hospitalizations was larger in women than men (791 versus 589 per 1000).

While obesity was associated with increased hospitalization rates for all cardiovascular disease-related primary causes (e.g. myocardial infarction, congestive heart failure, stroke, etc.), the biggest relative impact of obesity was seen on hospitalization for osteoarthritis (9 per 1000 in normal weight vs. 79 per 1000 - an almost 8-fold increase!).

Based on this clear evidence that overweight and obesity substantially increases the number of hospitalizations, the authors emphasize that continued research on obesity treatment and prevention (I would add: as well as increasing access to obesity treatments) is essential.

AMS
Edmonton, Alberta

Yesterday, I came across a recent article on osteoarthirits by Simon Juang from the University of British Columbia, published in the latest issue of Parkhurst Exchange.

Given that osteoarthritis (OA) is probably the most common cause of pain and disability in patients with obesity, as a non-expert, I found the article most informative and relevant.

The following are some of the key pieces of information I gleaned from this overview:

First of all, I was surprised to learn that OA is not always painful, but on the other hand, that not all joint pain, simply because there may be radiological signs of OA, is actually due to OA. In fact, quite often the pain may result from the structures around the joint, i.e. the muslces, ligaments, tendons, bursae, osteophytes, injury, etc. As the course of treatment may well be different, proper diagnosis of the actual source of pain is essential.

The 4 pillars of OA management include:
- patient education
- non-pharmacological interventions
- drug therapy
- appropriate referral

The 4 goals of treatment are:
- reducing pain
- maintaining range and strength
- preserving function
- dercreasing the rate of progression

As expected, the basic joint health program starts with “optimal weight”, whereby however, Huang automatically assumes that this can be fixed by “proper diet”, best achieved by referral to a dietitian (readers of these pages will likely appreciate that if obesity management was indeed that simple, we would probably not have a crisis).

Other aspects of the joint program involve physiotherapists (exercises, heating pads, nerve stimulation, etc.), occupational therapists (activities of daily living), but also orthoticists, or podiatrists.

The article also lists a number of useful resources for patients, which I list here:

- The Athritis Society
- Arthritis Resource Guide for BC
- OASIS (OsteoArthritis Service Integrated System, Vancouver Coastal Health)
- Joint Health, Arthritis Consumer Experts
- Alberta Bone and Joint Institute
- Canadian Orthopedic Foundation

Remember, while managing pain and increasing mobility will not automatically result in weight loss, impaired mobility is certainly a major barrier to any weight management program.

AMS
Edmonton, Alberta

Based on the number of patient who have told me that their orthopedic surgeons require them to lose unrealistic amounts of weight before they will be considered for knee surgery, I would assume that surgical outcomes in patients with severe obesity are so miserable that few surgeons are willing to risk surgery.

But is this really true?

This question was addressed by Rajgopal and colleagues from Western University, London, Ontario just out in the Journal of Arthroplasty.

This study evaluated the 1-year outcomes in 550 patients who underwent primary total knee arthroplasty between 1987 and 2004 with a primary diagnosis of osteoarthritis. Outcomes were measured using the Western Ontario and McMaster Osteoarthritis Index [WOMAC].

Although 1-year outcomes were indeed slightly worse for patients with a BMI >40, compared to patients with lower BMIs, it was the severely obese patients that actually showed greater improvement in function compared with normal weight or less obese patients.

This data is quite consistent with previous reports that obesity per se should neither be a contraindication for joint replacement surgery nor is it a predictor of less satisfaction or pain relief in these patients, despite somewhat less mobility.

Denying patients joint replacements because of their weight or expecting them to lose unrealistic amounts of weight prior to surgery is not evidence-based medicine.

AMS
Toronto, Ontario