Effects of a Three-Month Low Calorie Diet Weight Loss Intervention on Knee Replacement Outcomes

A Pilot Study Investigating the Effects of a Three-Month Low Calorie Diet Weight Loss Intervention on Knee Replacement Outcomes

Total Knee Replacement (TKR) significantly improves function, pain, and overall quality of life in patients with end-stage arthritis of the knee. However, studies show that obesity increases complications and costs associated with TKR. The American Academy of Orthopaedic Surgeons (AAOS) clinical guidelines recommend that patients with a BMI > 25kg/m2 lose 5% of their body weight prior to surgery. Consequently, although it is not clear how to patients or providers achieve weight loss in this population, some providers and hospitals decline to perform TKR in patients with obesity. Low Calorie meal replacement diets (LCD) are a feasible way to safely promote short-term weight loss of 8-15% at 3-6 months prior to some elective surgeries.

This is a pilot efficacy study to test whether a short-term program using a 3-month LCD leads to weight loss and improved patient reported and functional outcomes. 75 patients eligible for knee replacement surgery and willing to undergo non-operative weight management treatment at NYU Langone Comprehensive Obesity Center. This study will establish feasibility and weight loss outcomes in preparation for a multicenter effectiveness trial.

Inclusion Criteria:

• BMI 35-45 kg/m2
• Any ethnicity
• Able to speak, read, and write in English
• Have knee replacement surgery already planned by the surgeon
• Plan to undergo knee replacement surgery within 3-6 months post LCD intervention
• Willing to commute to NYU Langone Weight Management Clinic at the start of the dietary intervention, midway through, and end of intervention

Exclusion Criteria:

• Uncontrolled type 2 diabetes, defined as HbA1c > 9%
• If smokes cigarettes, must go through a 6 week cessation program first
• Type 1 diabetes
• Whey protein allergies
• Soy allergies
• Anyone in whom rapid weight loss is not indicated (e.g., ESRD or cirrhosis, metabolic cancer, abnormal 3 times UL liver enzyme labs)
• Current untreated or uncontrolled eating disorder (e.g., binge eating, bulimia)
• Rheumatoid arthritis
• In case a previous knee replacement surgery was done, the participant should wait at least 1 year from previous date of surgery
• Undergoing simultaneous bilateral knee replacement
• Enrolled in a formal weight loss program
• Taking anti-obesity medications
• Coexisting psychotic conditions requiring hospitalization or more intense treatment (e.g., bipolar mood disorder, severe depression)
• Abnormal CBC, and uric acid, must be treated prior to start of intervention
• Higher than 5.5 mU/L or lower than 0.3 mU/L TSH must be treated prior to start of LCD intervention