Biology is complicated. New research from France has reinforced that old truism. Researchers looked into implant survival rates for more than 1,600 patients and found that body mass index (BMI) and body weight are poor predictors of implant failure.
Their study, “Inconsistent relationship between body weight/body mass index prior to total knee arthroplasty and the 12-year survival,” appears in October 18, 2019 edition of The Knee.
Co-author Professor Jean-Yves Jenny, an orthopedic surgeon at the University Hospital Strasbourg in France, explained why he tackled this somewhat controversial subject to OTW, “We had the feeling that patients with revision TKA [total knee arthroplasty] were not clinically different than patients for primary TKA.”
Thus, they conducted a multicenter national retrospective study and, eventually, looked at data for 1,604 TKA patients.
The authors were able to collect 10-year follow-up data and found that the influence of body weight and body mass index on the implant survival rate was not well correlated. The researchers found that while there WAS a significant influence of the body weight on the 12-year implant survival rate for any reason, including infection, the influence did NOT correlate proportionally to either body weight or BMI. The research team found that BMI did not influence the 12-year implant survival rate for any reason, whether for any mechanical reason or for infection.
Professor Jenny told OTW, “BMI is a poor prognostic factor when considering long term survival of mobile bearing TKAs. Body weight had a significant impact for incident of revision for infection, but it was not proportional; probably there are confounding factors. There is no reason NOT to implant TKA in obese patients when considering long-term survival.”
