The Radiographic Prepatellar Fat Thickness Ratio Correlates with Infection Risk following Total Knee Arthroplasty




Hogan, Sean
Bates, Christopher
Burge, Ross
Sanchez, Hugo
Wagner, Russell


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  1. Purpose Obesity has been associated with complications following a total knee arthroplasty (TKA). Surgical Site Infection (SSI) following TKA is one of the feared complications as it increases revision rates, costs, and stress to the patient. There is conflicting evidence in the literature regarding BMI and risk of infection after TKA and some studies have suggested that site-specific fat distribution may be a better metric for determining risk of postoperative infections. Here we investigate the correlation of soft tissue distribution about the knee to surgical site infection following TKA.
  2. Methods We retrospectively review 572 patients who underwent primary TKA at a single institution from 2006 to 2010. We introduce the Prepatellar Fat Thickness Ratio (PFTR) as a radiographic means to quantitatively assess fat distribution about the knee and evaluate this measurement’s ability to assess the risk of developing a SSI following TKA.
  3. Results The PFTR was shown to be a better predictor of SSI than BMI in both the univariate (p=0.05) and multivariate (p=0.01) analyses.
  4. Conclusions While BMI cannot fully account for variations in adipose distribution, the PFTR may account for this variability and may be a helpful tool for assessing a patient’s preoperative risk of SSI after TKA.


Research Appreciation Day Award Winner - 2018 UNT Health Science Center, 2018 Resident Research Award - 1st Place