Measuring Patellofemoral Forces and Pressures in a Simulated Operating Room Environment

Abstract 

The purpose of this study was to use a validated capacitive pressure (Novel Electronics, Inc, St Paul, Minn) in the measurement and distribution of patellofemoral forces and pressures during simulated operative procedures. Six fresh frozen cadaver knees were evaluated through a range of motion and observations recorded in native knees (NKNP) with sequential resurfacing of tibiofemoral (RKNP) and patellofemoral (RKRP) articulations with standard and gender (GKRP) components. Significant lateral-medial maximum force differentials were observed for all conditions. Significant lateral-medial peak pressure differentials were observed in RKNP and RKRP. A significant decrease in lateral maximum force from RKRP to GKRP (P = .01) was observed. Significant increases in lateral peak were seen from NKNP to RKNP (P = .04) and RKNP to RKRP (P = .047), whereas a significant decrease was seen from RKRP to GKRP (P < .01). Achieving a quantitative intraoperative assessment of patellar tracking and soft tissue balancing may offer benefits in terms of intraoperative decision making. This is the first reported study to simulate quantitative, intraoperative assessments of patellofemoral pressure and force.

Keywords: total knee arthroplasty, patellofemoral joint, contact area, pressure, force-sensing device