Calcium phosphate cements (CPCs) are clinically used as injectable materials to fill bone voids and to improve hardware fixation in fracture surgery. In vivo they are dynamically loaded; nonetheless little is known about their fatigue properties. The aim of this study was to, for the first time, investigate the fatigue performance of a high-strength, degradable (brushitic) CPC, and also evaluate the effect of cement porosity (by varying the liquid to powder ratio, L/P) and the environment (air at room temperature or in a phosphate buffered saline solution, PBS, at 37 °C) on the fatigue life. At a maximum compressive stress level of 15 MPa, the cements prepared with an L/P-ratio of 0.22 and 0.28 ml/g, corresponding to porosities of approximately 12% and 20%, had a 100% probability of survival until run-out of 5 million cycles, in air. When the maximum stress level, or the L/P-ratio, was increased, the probability of survival decreased. Testing in PBS at 37 °C led to more rapid failure of the specimens. However, the high-strength cement had a 100% probability of survival up to approximately 2.5 million cycles at a maximum compressive stress level of 10 MPa in PBS, which is substantially higher than some in vivo stress levels, e.g., those found in the spine. At 5 MPa in PBS, all specimens survived to run-out. The results found herein are important if clinical use of the material is to increase, as characterisation of the fatigue performance of CPCs is largely lacking from the literature.

磷酸钙骨水泥（CPC）在临床上被用作可注射材料，以填充骨空隙并改善骨折手术中的硬件固定。体内它们是动态加载的；然而，人们对其疲劳性能知之甚少。这项研究的目的是第一次研究高强度，可降解（硬质合金）CPC的疲劳性能，并评估水泥孔隙率的影响（通过改变液粉比L / P）和环境（室温下的空气或在37°C的磷酸盐缓冲盐溶液PBS中）对疲劳寿命的影响。在最大压缩应力水平为15 MPa时，L / P比为0.22和0.28 ml / g的水泥（孔隙率分别约为12％和20％）具有100％的生存率，直至耗尽。 500万次循环，在空中。当最大应力水平或L / P比增加时，生存的可能性降低。在37°C的PBS中进行测试会导致样品更快失效。体内压力水平，例如在脊柱中发现的水平。在PBS中压力为5 MPa时，所有标本都存活到耗尽。如果要增加材料的临床应用，此处发现的结果很重要，因为从文献上很难找到CPC的疲劳性能。