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Severe Obesity and Knee Replacements

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.

Toronto, Ontario

1 Comment

  1. One year of functional improvement may not the best endpoint. These new joint surfaces do wear out and the cement does loosen, we need the durrabilty measured somehow. The operation also requireds the knee the be hyperflexed intraperatively and this motion is often severly limited in the obese because of the soft tissue making the operaton much harder, needing more disection of the patella tendon. Then there is months of rehab to deal with. So they should have been able to provide more than 1 year of follow up.

    Bill Graber

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