The Stability of Three Commercially Available Implants Used in Medial Opening Wedge High Tibial Osteotomy

Abstract

This biomechanical study tested three commercially available fixation devices for medial opening wedge high tibial osteotomy (HTO). A medial opening wedge HTO model was created on replicate tibias. Fixation was achieved with one of three fixation devices: VS Osteotomy plate (EBI, Parsippany, NJ), Arthrex Osteotomy plate (Arthrex, Naples, Fla), and OsteoTrac plate (DJ Orthopedics Inc, Vista, Calif). For each fixation system, seven specimens were cyclically loaded in compression and torsion under physiologic loads on a servohydraulic machine. Mean axial stiffness was 2425 N/mm, 2358 N/mm and 2258 N/mm, respectively, for the EBI, Arthrex, and Alaron surgical plates. Mean torsional stiffness was 4.5 Nm/degree, 4.1 Nm/degree and 4.0 Nm/degree, respectively, for the EBI, Arthrex, and DJ Orthopedics surgical plates. Though the differences are not statistically significant between the three fixation devices (P=.74 for mean axial stiffness and P=.10 for mean torsional stiffness), there is insufficient statistical power to rule out a true difference. Using this replicate tibia model, all three fixation devices tested appear to successfully stabilize the osteotomy site with regards to physiologic axial and torsional loads.