Synchronization of calcium sulphate cement degradation and new bone formation is improved by external mechanical regulation

Abstract

A major challenge faced in the bone materials of weight-bearing without internal fixture support is the mismatch of material degradation and new bone formation, leading to weakening or even failure of the overall bony structure. This study demonstrated in the rat femur model that calcium sulphate cement degradation and new bone formation could be better synchronized by external mechanical force. An ascending force in line with calcium sulphate cement degradation could achieve bone healing in 37 days with ultimate load to failure of 87.00 AE 7.30 N, similar to that of intact femur (80.46 AE 2.79 N, p ¼ 0.369). In contrast, the healing process under either a constant force or no force illustrated significant residual defect volumes of 1.47 AE 0.44 and 4.08 AE 0.89 mm 3 (p < 0.001), and weaker ultimate loads to failure of 69.56 AE 4.74 and 59.17 AE 7.48 N, respectively (p < 0.001). Our results suggest that the mechanical regulation approach deserves further investigation and may potentially offer a clinical strategy to improve synchronization. ß

Poly(lactic-co-glycolic acid)-based composite bone-substitute materials

“…In order to meet the demands, artificial bone-substitute materials require a variety of properties to maintain bone strength at the area of bone defects and promote bone regeneration, including similar mechanical strength to bone tissue, excellent biocompatibility and biodegradability, as well as a porous network structure for cells to grow in [ [19] , [20] , [21] , [22] , [23] ]. The existing bone-substitute materials are summarized in Table 1 .…”

Analysis of the Osteogenic Effects of Biomaterials Using Numerical Simulation

“…The defect was assumed to be 1 cm × 1 cm and involved 36 elements, including the cortical and cancellous bone. This size has been used in many prior animal experiments [25, 29, 30]. …”

“…The extents of biomaterial degradation and osteogenesis were scanned in vivo at three time points (7, 17, and 27 days) with a micro-CT scanner (SkyScan 1176, Bruker-microCT, Kontich, Belgium). The CSC, instrument parameters, and scanning methods were the same as the control animal experiment described in Zhang et al [25], which restricted the rats in 47 × 35 × 20 cm 3 cages.…”

“…The implant material properties used were as follows: elastic moduli of 7000 and 2000 MPa and Poisson's ratio of 0.3 for two parts of the cortical bone; an elastic modulus of 900 MPa and Poisson's ratio of 0.3 for the cancellous bone; and an elastic modulus of 800 MPa and Poisson's ratio of 0.3 for the implant material. The joint force was assumed as 0.65 N, which is about one-third of an average rat body weight (204 g) [25]. For the material degradation time in the simulation, an iteration step length was 1 day.…”

“…Although constructing an experimental animal model has advantages such as intuitiveness and subjectivity [25], the need for long testing periods and susceptibility to numerous extraneous factors can be disadvantageous. This may limit the ability of researchers to observe any quantitative relationships between the implantation material and the bones.…”