Obesity and joint replacement

The size of the problem

Obesity is a global epidemic affecting upwards of 2.1 billion people.^1,2The obese are known to have an increased risk of coronary artery disease, hypertension, diabetes, peripheral vascular disease, obstructive sleep apnoea, hyperlipidemia, gastro-oesophageal reflux, gallstones, urinary stress incontinence, peripheral vascular disease, colon, breast and ovarian cancer, depression and other psychiatric disorders.^3,4 Our concern as orthopaedic surgeons is with the potential for increased incidence of osteoarthritis in the obese, the additional hazards of joint replacement surgery in this population and the associated medical ethics. Weight-bearing joints are abnormally and excessively loaded in obesity, causing articular cartilage failure. The metabolic influence of obesity potentiates this mechanical failure with an increased incidence of osteoarthritis and subsequently a more rapid degeneration.^4,5 The dilemma for the orthopaedic surgeon is when to offer surgery in the face of a reversible condition; if obesity is treated this may obviate joint replacement and reduce the risk and severity of obesity-related disease.

Obesity, joint disease and treatment

Total joint replacement (TJR) in the obese attracts more complications, poorer outcomes and higher revision rates.^6,7 Despite this, the vast majority of obese patients who undergo TJR are satisfied with these poorer than average outcomes and a strong argument can be made for arthroplasty treatment where effective obesity treatments are absent. The long list of comorbid diseases and increased surgical risks in obese patients demands multidisciplinary management. This is a demand rarely met. Diet and exercise programmes may be successful and results are sustained in a small proportion of patients, but modest temporary weight loss is more usual. About 340 000 bariatric operations are performed worldwide every year, providing rapid, effective and sustained weight loss and reduction in joint pain.⁸ However, bariatric surgery is expensive and often inaccessible to non-privately funded patients. Although obesity in the developed world represents a problem comparable with smoking,^1,9 the political will to drive an effective public health programme and generate cultural change seems conspicuously absent. While these conditions prevail, orthopaedic surgeons will continue to be faced with the dilemma of either performing surgery in suboptimal conditions or allowing pain and disability to continue uncorrected as obesity is treated with mixed results.