The Radiographic Prepatellar Fat Thickness Ratio Correlates With Infection Risk After Total Knee Arthroplasty

Area of Science:

• Orthopedic Surgery
• Radiology
• Infectious Disease

Background:

• Obesity is linked to complications following total knee arthroplasty (TKA).
• Surgical site infection (SSI) is a significant complication of TKA, increasing revision rates and healthcare costs.
• Existing research on body mass index (BMI) and TKA infection risk is conflicting; site-specific fat distribution may be a more accurate predictor.

Purpose of the Study:

• To investigate the correlation between soft tissue distribution around the knee and SSI after TKA.
• To introduce and evaluate the prepatellar fat thickness ratio (PFTR) as a quantitative radiographic measure for assessing infection risk.

Main Methods:

• Retrospective review of 572 patients undergoing primary TKA between 2006 and 2010.
• Introduction of the prepatellar fat thickness ratio (PFTR) as a novel radiographic metric.
• Evaluation of PFTR's ability to predict SSI risk compared to BMI.

Main Results:

• The PFTR demonstrated a statistically significant association with SSI risk.
• PFTR was a superior predictor of SSI compared to BMI in both univariate (P = .05) and multivariate (P = .01) analyses.

Conclusions:

• The PFTR may offer a more accurate assessment of SSI risk after TKA than BMI by accounting for variations in adipose tissue distribution.
• This radiographic measurement could serve as a valuable tool for preoperative risk stratification in TKA candidates.