The influence of obesity on the complication rate and outcome of total knee arthroplasty: a meta-analysis and systematic literature review.
BACKGROUND
The increase in the number of individuals with an unhealthy high body weight is particularly relevant in the United States. Obesity (body mass index ≥ 30 kg/m2) is a well-documented risk factor for the development of osteoarthritis. Furthermore, an increased prevalence of total knee arthroplasty in obese individuals has been observed in the last decades. The primary aim of this systematic literature review was to determine whether obesity has a negative influence on outcome after primary total knee arthroplasty.


METHODS
A search of the literature was performed, and studies comparing the outcome of total knee arthroplasty in different weight groups were included. The methodology of the included studies was scored according to the Cochrane guidelines. Data extraction and pooling were performed. The weighted mean difference for continuous data and the weighted odds ratio for dichotomous variables were calculated. Heterogeneity was calculated with use of the I2 statistic.


RESULTS
After consensus was reached, twenty studies were included in the data analysis. The presence of any infection was reported in fourteen studies including 15,276 patients (I2, 26%). Overall, infection occurred more often in obese patients, with an odds ratio of 1.90 (95% confidence interval [CI], 1.46 to 2.47). Deep infection requiring surgical debridement was reported in nine studies including 5061 patients (I2, 0%). Deep infection occurred more often in obese patients, with an odds ratio of 2.38 (95% CI, 1.28 to 4.55). Revision of the total knee arthroplasty, defined as exchange or removal of the components for any reason, was documented in eleven studies including 12,101 patients (I2, 25%). Revision for any reason occurred more often in obese patients, with an odds ratio of 1.30 (95% CI, 1.02 to 1.67).


CONCLUSIONS
Obesity had a negative influence on outcome after total knee arthroplasty.
Department of Orthopedic Surgery, Orthotrauma Research Center Amsterdam, University of Amsterdam, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. g.m.kerkhoffs@amc.nl
Gino M M J
GM
Kerkhoffs
Elvire
E
Servien
Warren
W
Dunn
Diane
D
Dahm
Jos A M
JA
Bramer
Daniel
D
Haverkamp
D019645:Arthroplasty, Replacement, Knee; D015992:Body Mass Index; D001835:Body Weight; D006801:Humans; D009765:Obesity / Q000150:complications*; D020370:Osteoarthritis, Knee / Q000150:complications / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology*; D011475:Prosthesis Failure; D016896:Treatment Outcome