Do obese patients benefit from a kinematic, appropriately designed total knee prosthesis?

Area of Science:

• Orthopedic surgery
• Biomedical engineering

Background:

• Modern total knee arthroplasty (TKA) often employs a bicruciate stabilized (BCS) technique, exemplified by the Journey 2 implant.
• The efficacy of BCS TKA across diverse patient weight classes remains an area requiring investigation.

Purpose of the Study:

• To evaluate the effectiveness of bicruciate stabilized TKA in patients across different body mass index (BMI) categories.
• To compare patient-reported outcome measures (PROMs) following BCS TKA in underweight, normal weight, overweight, obese, and severely obese individuals.

Main Methods:

• A retrospective study identified 292 patients who underwent primary BCS TKA between 2016 and 2017 with at least a 2-year follow-up.
• Patients were stratified into BMI groups: underweight/normal/overweight (<30 kg/m²), obese (30 to <35 kg/m²), and severely obese (≥35 kg/m²).
• PROMs, including Knee Society Score (KSS), Knee injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS JR), and Visual Analogue Scale (VAS), were analyzed using ANOVA and linear regression.

Main Results:

• No significant differences in baseline or follow-up PROMs were observed among the BMI groups (p > 0.10).
• Improvements in KSS and KOOS JR from pre-operative to post-operative states were comparable across all weight categories (p = 0.21 for KSS, p = 0.62 for KOOS JR).
• The mean age was 64.8 years, and the mean BMI was 32.3 kg/m², with distribution across groups as follows: 39.7% underweight/normal/overweight, 30.1% obese, and 30.1% severely obese.

Conclusions:

• Bicruciate stabilized TKA demonstrates consistent effectiveness regarding PROMs, irrespective of patient BMI.
• These findings support BCS TKA as a suitable and viable surgical option for patients across the entire spectrum of weight classes, from underweight to severely obese.