title: Obesity has no adverse effect on the outcome of unicompartmental knee replacement at a minimum follow-up of seven years.
abstract: The significance of weight in the indications for unicompartmental knee replacement (UKR) is unclear. Our hypothesis was that weight does not affect the long-term rate of survival of UKRs. We undertook a retrospective study of 212 UKRs at a mean follow-up of 12 years (7 to 22). The patients were distributed according to body mass index (BMI; < vs ≥ 30 kg/m(2)) and weight (< vs ≥ 82 kg). Kaplan-Meier survivorship analysis was performed and ten-year survival rates were compared between the sub-groups. Multimodal regression analysis determined the impact of the various theoretical contraindications on the long-term rate of survival of UKR. The ten-year rates of survival were similar in the two weight subgroups (≥ 82 kg: 93.5% (95% confidence interval (CI) 66.5 to 96.3); < 82 kg: 92.5% (95% CI 82.5 to 94.1)) and also in the two BMI subgroups (≥ 30 kg/m(2): 92% (95% CI 82.5 to 95.3); < 30 kg/m(2): 94% (95% CI 78.4 to 95.9)). Multimodal regression analysis revealed that weight plays a part in reducing the risk of revision with a relative risk of 0.387, although this did not reach statistical significance (p = 0.662). The results relating weight and BMI to the clinical outcome were not statistically significant. Thus, this study confirms that weight does not influence the long-term rate of survival of UKR.
authors.affiliation: CHU Rangueil, Institut de l'Appareil Locomoteur, 1 Avenue Jean Pouilhes, Toulouse, France. cavaignac.etienne@gmail.com
authors.forename: E
authors.initials: E
authors.lastname: Cavaignac
authors.forename: V
authors.initials: V
authors.lastname: Lafontan
authors.forename: N
authors.initials: N
authors.lastname: Reina
authors.forename: R
authors.initials: R
authors.lastname: Pailhé
authors.forename: M
authors.initials: M
authors.lastname: Wargny
authors.forename: M
authors.initials: M
authors.lastname: Warmy
authors.forename: J M
authors.initials: JM
authors.lastname: Laffosse
authors.forename: P
authors.initials: P
authors.lastname: Chiron
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods; D015992:Body Mass Index; D005260:Female; D062785:Hemiarthroplasty / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D053208:Kaplan-Meier Estimate; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D020370:Osteoarthritis, Knee / Q000601:surgery; D011475:Prosthesis Failure / Q000209:etiology; D012086:Reoperation; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome
keywords: Clinical outcome; Kaplan-Meier; Obesity; Survival; UKR; Weight