The impact of pre-operative obesity on weight change and outcome in total knee replacement: A prospective study of 529 consecutive patients

Michelle M Dowsey, D. Liew, James D. Stoney, P. F. Choong

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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 postoperatively. The patients were grouped according to their pre-operative body mass index (BMI) as follows: non-obese (BMI < 30 kg/m2), obese (BMI 3 30 to 39 kg/m2) and morbidly obese (BMI > 40 kg/m2). 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 ≥ 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).

Original languageEnglish
Pages (from-to)513-520
Number of pages8
JournalThe Journal of Bone and Joint Surgery, British Volume
Issue number4
Publication statusPublished - Apr 2010

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