The impact of pre-operative obesity on weight change and outcome in total knee replacement: a prospective study of 529 consecutive patients.
We carried out a prospective, continuous study on 529 patients who underwent primary total knee replacement between January 2006 and December 2007 at a major teaching hospital. The aim was to investigate weight change and the functional and clinical outcome in non-obese and obese groups at 12 months post-operatively. The patients were grouped according to their pre-operative body mass index (BMI) as follows: non-obese (BMI < 30 kg/m(2)), obese (BMI (3) 30 to 39 kg/m(2)) and morbidly obese (BMI > 40 kg/m(2)). The clinical outcome data were available for all patients and functional outcome data for 521 (98.5%). Overall, 318 (60.1%) of the patients were obese or morbidly obese. At 12 months, a clinically significant weight loss of > or =5% had occurred in 40 (12.6%) of the obese patients, but 107 (21%) gained weight. The change in the International Knee Society score was less in obese and morbidly obese compared with non-obese patients (p = 0.016). Adverse events occurred in 30 (14.2%) of the non-obese, 59 (22.6%) of the obese and 20 (35.1%) of the morbidly obese patients (p = 0.001).
Dowsey
M M
MM
Universityof Melbourne,Melbourne, Australia.
Liew
D
D
Stoney
J D
JD
Choong
P F
PF
D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000534:rehabilitation*; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000503:physiopathology; D009767:Obesity, Morbid / Q000150:complications / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000601:surgery; D011184:Postoperative Period; D011446:Prospective Studies; D011788:Quality of Life; D020127:Recovery of Function; D016896:Treatment Outcome; D015430:Weight Gain; D015431:Weight Loss