Laitinen O, Törmälä P, Taurio R, Skutnabb K, Saarelainen K, Iivonen T, Vainionpää S
Department of Clinical Sciences, College of Veterinary Medicine Hämeentie, Helsinki, Finland.
Biomaterials. 1992;13(14):1012-6. doi: 10.1016/0142-9612(92)90152-e.
To evaluate the mechanical properties of absorbable braided poly(L-lactide) (PLLA) fibre implants, 2.0 and 3.2 mm in diameter, maximum load defined as tensile load carrying capacity, elongation and axial rigidity were investigated after immersion in phosphate-buffered distilled water at 37 degrees C and pH 6.1 and after subcutaneous implantation in rabbit. The results confirm earlier indications that PLLA degrades faster in vivo than in vitro. The non-sterilized 2.0 mm implants lost 69% of initial tensile load carrying capacity in 46 wk in vitro. In vivo the loss of tensile load carrying capacity of the 2.0 and 3.2 mm implants was most marked between 6 to 12 wk. After 48 wk in vivo 2.0 and 3.2 mm implants retained 3 and 4% of initial tensile load carrying capacity respectively. Both in vitro and in vivo, elongation diminished in the same way as the maximum load. In vitro, mean axial rigidity of unsterilized 2.0 mm implants was 64 N during the first 34 wk but fell to 31 N at 46 wk. In vivo the initial mean axial rigidity of the 2.0 and 3.2 mm implants was 29 and 95 N respectively. At 24 wk the mean axial rigidity was 2 N in both implants.
为评估直径2.0毫米和3.2毫米的可吸收编织聚L-丙交酯（PLLA）纤维植入物的机械性能，研究了其在37摄氏度、pH值6.1的磷酸盐缓冲蒸馏水中浸泡后以及在兔皮下植入后的最大负荷（定义为拉伸负荷承载能力）、伸长率和轴向刚度。结果证实了早期的迹象，即PLLA在体内比在体外降解得更快。未灭菌的2.0毫米植入物在体外46周内失去了69%的初始拉伸负荷承载能力。在体内，2.0毫米和3.2毫米植入物拉伸负荷承载能力的损失在6至12周最为明显。在体内48周后，2.0毫米和3.2毫米植入物分别保留了初始拉伸负荷承载能力的3%和4%。在体外和体内，伸长率的降低方式与最大负荷相同。在体外，未灭菌的2.0毫米植入物在前34周的平均轴向刚度为64牛，但在46周时降至31牛。在体内，2.0毫米和3.2毫米植入物的初始平均轴向刚度分别为29牛和95牛。在24周时，两种植入物的平均轴向刚度均为2牛。
