Injectable calcium phosphate cements (CPCs) are emerging as promising materials to replace nonbiodegradable poly(methyl methacrylate; PMMA) cements currently used for minimally invasive treatment of vertebral body fractures. Recent approaches towards the improvement of the mechanical properties of CPC, i.e. CPC modification with reinforcing poly(lactic-co-glycolic acid; PLGA) fibers, has proven successful to increase the strength of the cement and the breaking energy. The mechanical properties of such fiber-reinforced CPCs cements are still, however, not suitable for clinical applicability in partial or full load-bearing defects.

In this work, in order to further improve the mechanical properties of PLGA-reinforced CPC, PLGA fibers with different cross-sectional shape (circular and lobular) and different length (1 mm and 1.5 mm) were used. The CPC composites with PLGA fibers, independent of cross-sectional shape and length, showed a statistically significant increase in work of fracture and strength compared to pure CPC as well as to previously reported values.[1,2] Furthermore, the PLGA fibers with a circular cross-sectional shape had the strongest effect on the work of fracture, whereas fibers with lobular cross-sectional shape had a more prominent effect on CPC composites flexural and compression strength. The observed mechanical behavior was attributed to the different surface areas and critical fiber lengths.