Medial opening-wedge high tibial osteotomy (HTO) has been used to treat osteoarthritis of the medial compartment of the knee. However, this makes the proximal tibia a highly unstable structure and causes the plate to be a potential source of mechanical failure. Consequently, proper design and material use of the fixation device are essential in HTO, especially for overweight or full-weight-bearing patients.
This study investigated the biomechanical effects of the TomoFix plate composed of conventional titanium (Ti) in comparison to plates composed of carbon short-fiber-reinforced (CSFR) polyetheretherketone (PEEK) and carbon long-fiber-reinforced (CLFR) PEEK, in medial opening-wedge HTO. A medial opening was simulated with various HTO plate models subjected to a 2500 N vertical load simulating the peak walking force using a validated knee-joint finite-element (FE) model. The stress on the plate and the bone, the contact stress on the menisci and articular cartilage, as well as wedge micromotion were measured.
The results of the FE analysis indicated that the Ti plate showed the best functional outcome in terms of micromotion. However, the CSFR PEEK plate showed a positive effect on relieving stress shielding. In addition, there was less contact stress on the meniscus and articular cartilage with the CSFR PEEK plate in comparison to CLFR PEEK and Ti plates.
These results can provide insights into the design of high-performing composite HTO plates to produce more desirable biomechanical effects.