The study of the effect of body mass index on long-term revision rate after total knee arthroplasty

doi:10.3969/.issn.1674-3245.2017.06.014

Abstract：Objective To explore the influence of body mass index on long-term revision of patients who had received total knee arthroplasty (TKA). Methods A retrospective study was carried out for the patients who received primary TKA in our hospital from January 2002 to December 2005. A total of 713 patients were recruited to this study. The patients were divided into three groups:normal weight (BMI<25 kg/m2),overweight (25 kg/m2≤BMI<30 kg/m2)and obese(BMI≥ 30 kg/m2). Statistical analysis was conducted to investigate the motive for early revision TKA and long-term revision TKA,and the differences of the revision rate and risk of revision TKA among the three groups was examined. Results Infection was the main motive for early revision TKA,and prosthetic damage or fracture and aseptic loosening were the main motives for long-term revision TKA. The percentage of primary TKA revisions at 5 years was 7.6% for the obese group,3.9% for the normal weight group and 3.6% for the overweight group,and there was no significant difference between the three groups (P=0.1060). The percentage of primary TKA revisions at 10 years was 15.1%for the obese group,6.5% for the normal weight group and 7.6%for the overweight group,and the difference between the three groups was statistically significant (P=0.0048). Ten years after the primary TKA,obese patients had an 84% increase(OR=1.84,95%CI,1.59-2.13)in the risk of revision versus the normal weight patients;overweight patients had a 14% increase (OR=1.14,95%CI, 0.63-1.91)in the risk of revision versus the normal weight patients. Conclusion Patient BMI level is associated with the long-term revision rate after TKA. Losing weight before or after TKA may decrease the long-term revision rate.