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

Abstract

Modern total knee arthroplasty (TKA) using the Journey 2 implant utilizes a bicruciate stabilized (BCS) technique. However, whether bicruciate stabilized TKA is equally effective across weight classes is unknown. We identified patients who underwent primary bicruciate stabilized TKA during 2016 and 2017, at a single institution. All included patients had, at minimum, 2-year follow-up. Patients were categorized into body-mass index (BMI) groups as follows: underweight, normal, or overweight (<30 kg/m²), obese (≥30 to <35 kg/m²), and severely obese (≥35 kg/m²). Patient reported outcome measures (PROMs) were measured at baseline. Both KSS and KOOS JR, along with the Visual Analogue Scale (VAS), were also recorded at follow-up. Pre-operative, post-operative, and pre-to post-operative changes in PROMs were analyzed using analysis of variance (ANOVA) and linear regression. The 292 patients had a mean age of 64.8 years and mean BMI of 32.3 kg/m². There were 116 (39.7%) patients in the underweight, normal, or overweight group, 88 (30.1%) in the obese category, and 88 (30.1%) in the severely obese group. There were no differences between PROMs at baseline or at follow-up (p > 0.10 for all comparisons). There were also no differences in the improvement from pre-to post-operative KSS (p = 0.21) and KOOS JR (p = 0.62). Bicruciate stabilized TKA has similar effects on PROMs across BMI groups. These results suggest that bicruciate stabilized TKA is a viable treatment option both for low-weight and high-weight patients.