Arya M. Sharma, MD

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

Feet are remarkably complex structures exquisitely designed to buffer and carry the weight of our bodies. Whether standing, running, jumping, hopping, skipping - the feet do it all. Not surprisingly, painful feet affect the whole organism.

Interestingly, not much is known about the impact of increased body weight on foot architecture in kids. This knowledge is of course of great importance for orthopaedic and paediatric physicians with regard to prevention, clinical treatment and management of foot problems but also of obesity.

Now, Marlene Mauch and colleagues from the University of Tuebingen, Germany, studied the foot morphology of normal, underweight and overweight children in 1450 boys and 1437 girls aged 2-14 years (Int J Obesity). Foot morphology was measured using a three-dimensional (3D) foot scanner (Pedus, Human Solutions Inc., Germany) in a bipedal upright position. Twelve relevant 3D foot measures were recorded, as well as the children’s age, gender, height and mass.

Five foot types were identified: flat, robust, slender, short and long feet. While normal weight children displayed an almost equal distribution of all foot types throughout childhood, overweight and obese children were more likely to have flat and robust feet, whereas underweight children tended to have slender and long feet.

The authors not only conclude that excess weight may have a significant effect on foot morphology but may also increase the risk for foot discomfort as a result of various musculoskeletal disorders. This in turn may keep the overweight children from being active thereby further promoting weight gain.

Clearly, the role of foot morphology and the maintenance of foot health in overweight and obese kids deserves more attention and further study.

I would add that careful analysis of foot morphology and recommendation of proper footwear, orthotics and exercises should be part of every assessment of an overweight kid - damage to feet resulting from well-meant but ill-advised physical activity at an early age could precipitate lifelong foot problems and prove a major obstacle to long-term weight management.

AMS
Edmonton, Alberta

On Saturday (June 7), I presented at a session on How Obesity Affects Orthopaedic Care at the 2nd joint meeting of the American and Canadian Orthopaedic Associatons in Quebec City.

Despite being on the last day of this meeting, the session was surprisingly well attended, probably a reflection of the increasing awareness of issues around orthopaedic care for patients with severe obesity.

While I presented my usual take on how obesity is now a widespread chronic disease, I did take away some interesting aspects related to orthopaedic care of patients with obesity that I was unaware of.

For example, George Russell (Jackson, Mississippi) in his talk mentioned the issue that in severely obese patients immobilization of fractures with a plaster cast poses a significant problem due to the “cushioning” effect of the surrounding adipose tissue. This results in an increased risk of “non-union”, often requiring additional internal or external fixation to ensure healing.

Russell also presented an interesting view of how differences in body fat distribution pose specific problems in orthopedic surgery on hips and knees. Thus, in patients with the “large belly - thin limb” phenotype, the operation on the limbs is relatively easy, but, given the association between large bellies and cardiometabolic risk, these patients are at greater risk for poor wound healing and cardiovascular problems. In contrast, patients with “large limbs - thin bellies” present problems related to the size of the limbs resulting in a greater risk for bleeding and wound infections. Obviously, patients with “large bellies - large limbs” are at increased risk for both types of complications.

In a talk on orthopaedic problems in childhood obesity, Benjamin Alman (Sick Kids, Toronto) mentioned the issue of “relatively” (i.e. in relationship to their body mass) lower bone density in children with overweight and obesity, an issue that may increase the likelihood of traumatic fractures in these kids - again, something I had not previously thought much about.

Bassam Masri (UBC, Vancouver) confirmed that despite slightly greater risk and less functionality following joint replacement in patients with severe obesity, their satisfaction is no smaller than that or non-obese patients - clear indication that obese patients should not be denied surgery simply because of their size. But don’t expect to see spontaneous weight loss after surgery - in fact weight sometimes even goes up in overweight patients following surgery (I have blogged on this before).

I was particularly happy to note that all three surgeons called upon their colleagues to show compassion and deliver care with the same professional attitudes with which they approach their non-obese patients.

Overall, a most interesting session. I am delighted to see the orthopaedic surgeons taking this great interest in this (unfortunately) increasingly important issue.

AMS
Edmonton, Alberta

Overweight and obesity are well-established risk factors for osteoarthritis and a major factor in driving the increasing demand for hip and knee replacements.

How does being overweight or obese affect functional outcomes of hip surgery?

This question was addressed by André Busato and colleagues from the Institute for Evaluative Research in Orthopaedic Surgery, University of Berne, Switzerland in a paper just out in Obesity Surgery.

Busato and colleagues quantified the role of high preoperative BMI on long-term pain status and functional outcome after total hip replacements in a multi-center cohort of 20,553 primary hip replacements (18,968 patients) and 43,562 postoperative clinical examinations for a follow-up period of up to 15 years.

Despite equal pain relief in obese and lean patients, there was an almost perfect dose-effect relationship between preoperative BMI and decreased ambulation during the follow-up period.

This means that despite improvement in pain, patients with higher BMIs tend to regain less mobility following the hip replacement.

While the authors suggest that lifestyle management and pre- or post-surgical weight loss will improve outcomes, this has yet to be demonstrated in a large randomized trial.

It may well be that other factors unrelated to pain may be affecting mobility in heavier patients. In fact many factors that may have led to the weight gain in the first place may not be resolved simply by having a hip replacement.

This observation is not different from that of a previous study that I recently blogged on which reported that back surgery for pain relief in patients with spinal stenosis does not automatically result in increased mobility or weight loss.

Obesity is a multifactorial chronic disease and the long-term impact of educational and behavioural interventions is modest at best.

When present, obesity has to be addressed with the same interdisciplinary acumen and persistence as any other chronic disease.

AMS
Edmonton, Alberta