In Silico Modeling Validation and Contact Pressure Distribution Comparison Analysis of Conventional and Robotic-Assisted Unicompartmental Knee Arthroplasty.

Abstract

Unicompartmental knee arthroplasty (UKA) improves recovery, but optimizing load remains challenging. This study measures tibiofemoral contact pressures after conventional and robotic UKA in cadavers and validates a finite element (FE) model against experimental data. Sixteen fresh-frozen cadaveric lower limbs underwent medial UKA with conventional cutting guides (n = 8) or CORI robotic assistance (n = 8). Medial (implanted) and lateral (native) compartment pressures were recorded from 0° to 90° using pressure film sensors. The FE model replicated and was validated against these measurements. Medial compartment pressure decreased significantly from 1.864 MPa at 0° to 0.252 MPa at 90° (p < 0.05). The lateral compartment showed a similar significant decrease from 0.733 MPa to 0.320 MPa (p < 0.05). No significant differences were observed between conventional and robotic-assisted techniques (p > 0.05). The FE model demonstrated strong agreement with the measured data, with r² values of 0.9994 (medial) and 0.9962 (lateral). Conventional and robotic-assisted UKA techniques demonstrated similar contact pressure profiles. However, increased force and area in the native lateral compartment may predispose to postoperative degeneration. The FE model reliably predicted contact behavior and may be especially useful in refining conventional UKA techniques. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.