There is a need to replace surgical plates and screws in orthopedic surgery. Absorbable polymers are an alternative to metal where load bearing is of a less concern. Polycaprolactone (PCL) is biocompatible, yet it has low mechanical strength and its surface chemistry does not promote cell adhesion. The objective of this work was to create PCL adhesive blends with poly(glycolic) acid (PGA), thermoplastic starch (TPS), chitosan, and tricalcium phosphate (TCP) to be used as potential fracture fixation devices. The differential scanning calorimetry (DSC) data showed that the primary melting points (T m1 C) of blends were often lower than PCL, with the exception of chitosan blends, which may indicate an improvement for surgical use. PCL/PGA blends showed secondary and tertiary melting points (T m ) and enthalpies (ΔH m ) indicating poor miscibility of PGA in the blends. The binary PCL/TCP mixture has a higher enthalpy compared to the binary PCL/PGA blend, but the secondary melting temperature is lower in ternary mixtures. Ternary blends of PCL/PGA/TCP, however, retained the adhesive strength of the parent PCL adhesive while having an improvement in hydrophilicity. These blends are recommended for fracture fixation devices especially in low load-bearing applications such as maxillofacial surgery, orthopedics, and neurosurgery.

Understanding the cement injection behaviour during vertebroplasty and accurately predicting the cement placement within the vertebral body is extremely challenging. As there is no standardized methodology, we propose a novel method using reproducible and pathologically representative flow models to study the influence of cement properties on injection behaviour. The models, confined between an upper glass window and a lower aluminium plate, were filled with bone marrow substitute and then injected (4, 6 and 8 min after cement mixing) with commercially available bone cements (SimplexP, Opacity+, OsteopalV and Parallax) at a constant flow rate (3 mL/min). A load cell was used to measure the force applied on the syringe plunger and calculate the peak pressure. A camera was used to monitor the cement flow during injection and calculate the following parameters when the cement had reached the boundary of the models: the time to reach the boundary, the filled area and the roundness. The peak pressure was comparable to that reported during clinical vertebroplasty and showed a similar increase with injection time. The study highlighted the influence of cement formulations and model structure on the injection behaviour and showed that cements with similar composition/particle size had similar flow behaviour, while the introduction of defects reduced the time to reach the boundary, the filled area and the roundness. The proposed method provides a novel tool for quick, robust differentiation between various cement formulations through the visualization and quantitative analysis of the cement spreading at various time intervals.

No abstract

No abstract

No abstract