Yoon Jung-Ro, Ko Young-Rok, Shin Young-Soo
Department of Orthopedic Surgery, Veterans Health Service Medical Center, Seoul, Republic of Korea.
Medicine (Baltimore). 2018 Apr;97(17):e0558. doi: 10.1097/MD.0000000000010558.
Although many factors are known to influence the polymerization time of bone cement, it remains unclear which bone cement shape predicts the precise polymerization time. The purpose of this study was to investigate whether different cement shapes influenced polymerization time and to identify the relationship between cement shape and ambient operating theater temperature, relative humidity, and equilibration time.
Samples were gathered prospectively from 237 patients undergoing primary total knee arthroplasty. The cement components were made into 2 different shapes: lump and pan. The time at which no macroscopic indentation of both cement models was possible was recorded as the polymerization time.
There was no significant difference between hand mixing (lump shape: 789.3 ± 128.4 seconds, P = .591; pan shape: 899.3 ± 152.2 seconds, P = .584) and vacuum mixing (lump shape: 780.2 ± 131.1 seconds, P = .591; pan shape: 909.9 ± 143.3 seconds, P = .584) in terms of polymerization time. Conversely, the polymerization time was significantly shorter for Antibiotic Simplex (lump shape: 757.4 ± 114.9 seconds, P = .001; pan shape: 879.5 ± 125.0 seconds, P < .001) when compared with Palacos R+G (lump shape: 829.0 ± 139.3 seconds, P = .001; pan shape: 942.9 ± 172.0 seconds, P < .001). Polymerization time was also significantly longer (P < .001) for the pan shape model (904 ± 148.0 seconds) when compared with the lump shape model (785.2 ± 129.4 seconds). In addition, the polymerization time decreased with increasing temperature (lump shape: R = 0.334, P < .001; pan shape: R = 0.375, P < .001), humidity (lump shape: R = 0.091, P < .001; pan shape: R = 0.106, P < .001), and equilibration time (lump shape: R = 0.073, P < .001; pan shape: R = 0.044, P < .001).
The polymerization time was equally affected by temperature, relative humidity, and equilibration time regardless of bone cement shape. Furthermore, the pan shape model better reflected the cement polymerization time between implant and bone compared with the lump shape model. The current findings suggest that, clinically, constant pressure with the knee in <45° of flexion needs to be applied until remaining pan shaped cement is completely polymerized.
尽管已知许多因素会影响骨水泥的聚合时间，但尚不清楚哪种骨水泥形状能准确预测聚合时间。本研究的目的是调查不同的骨水泥形状是否会影响聚合时间，并确定骨水泥形状与手术室环境温度、相对湿度和平衡时间之间的关系。
前瞻性收集237例行初次全膝关节置换术患者的样本。将骨水泥成分制成两种不同形状：块状和盘状。记录两种骨水泥模型均无法出现宏观压痕的时间作为聚合时间。
在聚合时间方面，手工搅拌（块状：789.3±128.4秒，P = 0.591；盘状：899.3±152.2秒，P = 0.584）和真空搅拌（块状：780.2±131.1秒，P = 0.591；盘状：909.9±143.3秒，P = 0.584）之间无显著差异。相反，与帕拉科斯R+G（块状：829.0±139.3秒，P = 0.001；盘状：942.9±172.0秒，P < 0.001）相比，抗生素单纯型骨水泥（块状：757.4±114.9秒，P = 0.001；盘状：879.5±125.0秒，P < 0.001）的聚合时间显著更短。与块状模型（785.2±129.4秒）相比，盘状模型（904±148.0秒）的聚合时间也显著更长（P < 0.001）。此外，聚合时间随温度升高（块状：R = 0.334，P < 0.001；盘状：R = 0.375，P < 0.001）、湿度升高（块状：R = 0.091，P < 0.001；盘状：R = 0.106，P < 0.001）和平衡时间延长（块状：R = 0.073，P < 0.001；盘状：R = 0.044，P < 0.001）而缩短。
无论骨水泥形状如何，聚合时间均同样受温度、相对湿度和平衡时间的影响。此外，与块状模型相比，盘状模型能更好地反映植入物与骨之间的骨水泥聚合时间。目前的研究结果表明，临床上，在膝关节屈曲<45°时需持续施加压力，直至剩余的盘状骨水泥完全聚合。
