title: Body mass index as a predictor of outcome in total knee replacement.
abstract: The clinical and radiographic outcomes of 326 total knee replacements (TKR) in 285 osteoarthritic patients with body mass index (BMI) greater than 30 kg/m2 were compared with the results of a matched group of 425 TKR in 371 patients with BMI less than 30 kg/m2. At an average follow-up of 75.9 (48-144) months the Knee Society score (KSS) in the obese patients had increased by 41.9 points, and the joint score by 43.7. In the non-obese group the KSS rose by 40.2 points and the joint score by 42.6 points. Although patients with BMI greater than 40 kg/m2 achieved a lower final KSS the 'absolute improvement' appeared to be independent of BMI. Of the obese patient group 4.9% underwent a revision of their TKR, compared with 3.1% of the non-obese group. Although linear osteolysis (radiolucency) rates were comparable, focal osteolysis rates were 5 times those of control subjects when the BMI exceeded 40 kg/m2. Ten-year survivorship figures were similar for both obese and non-obese patients.
authors.affiliation: Orthopaedic Department, St Mary's Hospital, Praed St, London W2 1NY, UK. DDMSpicer@AOL.COM
authors.forename: D D
authors.initials: DD
authors.lastname: Spicer
authors.forename: D L
authors.initials: DL
authors.lastname: Pomeroy
authors.forename: W E
authors.initials: WE
authors.lastname: Badenhausen
authors.forename: L A
authors.initials: LA
authors.lastname: Schaper
authors.forename: J I
authors.initials: JI
authors.lastname: Curry
authors.forename: K E
authors.initials: KE
authors.lastname: Suthers
authors.forename: M W
authors.initials: MW
authors.lastname: Smith
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods / Q000401:mortality; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011237:Predictive Value of Tests; D011336:Probability; D011475:Prosthesis Failure; D018570:Risk Assessment; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D015996:Survival Rate; D016896:Treatment Outcome