Polymethylmethacrylate Combine With Gelatin Microparticle Construct For Reduce Permeability For Cement Infiltration Of Osteoporotic Cancellous Bone

Objective: To evaluate the Polymethylmethacrylate combine with gelatin foam toreduce the permeability for cement infiltration of osteoporotic cancellous bone. Thesecondary objective is to demonstrate gelatin foam effect for PMMA cement biomechanics.Method: First, we use sieves divided the gelatin particle into three groups,0-125μm,125-250μm and250-500μm. And we mixed gelatin with PMMA in different weight.Second, compressive and bending test mold is made at room temperature (size isaccordance in ISO5833:2002). Third, the dynamic viscosity of PMMA was measured by arotational rheometer in the room temperature (20℃). Forth, twenty-two fresh bovinevertebral body from one calf were cut into cylinder by a trephine. The cylinders weredefatted with trichloroethylene, and decalcified with EDTA-Na2, and each specimen wasevaluated the porosity before test. The pressure was tested by a mechanical test machine.And permeability was calculated using Darcy’s law. Fifth, bone cement-gelatin particlemixture was observed by electron microscopy.Result: Compared with solid Polymethylmethacrylate bone cement, with the increasingof the gelatin particle diameter and the density. However there is no significant difference ofcompressive strength (P>0.05), but there is significant difference between1%with250-500μm and the control group (P<0.05). The permeability for cement infiltration of osteoporoticcancellous bone is decreased with the increasing of the added gelatin particle diameter andthe density. The same diameters gelatin particles in different density of each group, thepermeability decreases with the quality increases, and there is significant difference between2-3%with0-125μm with the solid PMMA (P<0.05); also the same density but differentdiameters gelatin particles in each group of bone cement, the permeability decreases with thedensity increases, and there is also significant difference between1%with125-500μm withsolid PMMA (P<0.05).Conclusion: Gelatin sponge particles added into the acrylic resin bone cement canreduce the permeability of the bone cement infiltrated into the cancellous bone, and compressive and flexural strength of the bone cement is not a significant impact after addingthe gelatin particles.