Weight Loss Before Total Knee Arthroplasty Was Not Associated with Decreased Postoperative Risks.

Area of Science:

• Orthopedic surgery
• Obesity medicine
• Biostatistics

Background:

• Surgeons often advise weight loss for obese patients prior to total knee arthroplasty (TKA).
• The impact of preoperative weight loss on TKA outcomes remains unclear.
• This study aimed to assess weight change patterns and their effect on TKA results.

Purpose of the Study:

• Determine the prevalence of preoperative weight loss in patients with obesity undergoing TKA.
• Identify predictors of weight loss in this patient population.
• Evaluate the association between preoperative weight change and key postoperative outcomes.

Main Methods:

• Retrospective analysis of 3,665 obese patients (BMI ≥30 kg/m2) undergoing primary TKA (2002-2019).
• Weight change was measured between 1-24 months pre-surgery and at surgery.
• Statistical models (logistic regression, Cox hazards) analyzed predictors and outcomes (infections, complications, revisions).

Main Results:

• Only 26% of patients lost ≥5 pounds; 20% gained weight.
• Weight loss of 10-<20 pounds was linked to increased risks of revision and periprosthetic joint infection (PJI).
• Weight gain >5 pounds correlated with higher odds of extended hospital stay and complications.

Conclusions:

• Substantial preoperative weight loss is uncommon in obese TKA patients.
• Achieving typical weight loss goals did not improve TKA outcomes.
• While healthy weight is beneficial, pre-TKA weight loss may not be sufficient to enhance outcomes for most obese patients.