Polycaprolactone blends for fracture fixation in low load-bearing applications

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.