The polymer Polyactive as a bone-filling substance: an experimental study in rabbits

Area of Science:

• Biomaterials Science
• Orthopedic Research
• Polymer Science

Background:

• Polyactive (PA) is a biocompatible, osteoconductive, and resorbable polymer.
• Investigating novel materials for bone-graft substitution is crucial for orthopedic applications.

Purpose of the Study:

• To evaluate the efficacy of Polyactive (PA) as a bone-graft substitute in a rabbit femur model.
• To compare the performance of two PA formulations (PA70/30 and PA60/40), with and without bone marrow incubation.

Main Methods:

• A critical-sized bone defect model was created in rabbit femurs.
• Porous PA cylinders were implanted, with one femur serving as a control.
• Analyses included dual-energy X-ray absorptiometry (DXA) and histological evaluation at multiple time points (4, 8, 26, 52 weeks).

Main Results:

• DXA confirmed increased bone mineral density in PA-filled defects compared to controls.
• Histology revealed significant bone regeneration, with 80-90% pore occupancy by new bone within 8 weeks.
• PA70/30 demonstrated faster bone formation than PA60/40; incubation with bone marrow caused inflammation but did not impede bone growth.

Conclusions:

• Both PA70/30 and PA60/40 are effective bone-graft substitutes, promoting osteoconduction and bone regeneration.
• PA70/30 appears more advantageous due to accelerated bone formation.
• PA shows good integration and potential for clinical use in bone defect repair.