Thordarson D B, Hedman T P, Yetkinler D N, Eskander E, Lawrence T N, Poser R D
Department of Orthopaedic Surgery, University of Southern California School of Medicine, Los Angeles 90033, USA.
J Bone Joint Surg Am. 1999 Feb;81(2):239-46. doi: 10.2106/00004623-199902000-00011.
Twenty-six paired, fresh-frozen cadaveric feet were disarticulated at the ankle joint, and the dome of the talus was potted. Stress-risers were placed along the medial, lateral, and posterior aspects of the calcaneus, and the specimen was loaded rapidly to failure in a testing machine to produce a type-IIB displaced intra-articular fracture according to the classification system of Sanders et al. One specimen of each pair was treated with standard internal fixation with bone-grafting (the control group), and the other was treated with similar fixation but with SRS (Skeletal Repair System) calcium phosphate bone cement placed in any osseous defect. All of the specimens were cured for twenty-four hours in a bath of saline solution at 37 degrees Celsius. The specimens were tested cyclically for ten cycles from zero to 100 newtons at one hertz and for 1010 cycles from zero to 350 newtons at one hertz. The deformation per cycle (millimeters per cycle), first-cycle deformation (millimeters), number of cycles to failure, and number of specimens withstanding the cyclical testing were calculated. The specimens were examined radiographically before and after fracture and after reconstruction and testing. A large difference in the results of the cyclical testing was noted. The specimens that had been augmented with the SRS bone cement had an average deformation of 0.00195 millimeter per cycle compared with 1.013 millimeters per cycle in the control group (p < 0.005). A similar magnitude of difference was noted when the results were stratified for good and poor-quality bone. Visual examination and radiographs demonstrated that a type-IIB displaced intra-articular fracture had been created reproducibly, and computed tomographic scans showed that nearly anatomical reconstruction had been achieved in all of the specimens. The computerized tomographic scans revealed good filling of the osseous voids and no evidence of failure of the cement after cyclical loading.
将26对新鲜冷冻的尸体足在踝关节处离断，将距骨穹隆部植入花盆。在跟骨的内侧、外侧和后侧放置应力集中器，然后将标本在试验机中快速加载直至破坏，以根据桑德斯等人的分类系统产生IIB型关节内移位骨折。每对标本中的一个采用标准内固定并植骨治疗（对照组），另一个采用类似的固定方法，但在任何骨缺损处放置SRS（骨骼修复系统）磷酸钙骨水泥。所有标本在37摄氏度的盐溶液浴中固化24小时。标本先从0到100牛顿以1赫兹的频率循环测试10个周期，然后从0到350牛顿以1赫兹的频率循环测试1010个周期。计算每个周期的变形量（毫米/周期）、第一周期变形量（毫米）、破坏时的周期数以及经受循环测试的标本数量。在骨折前、骨折后、重建后和测试后对标本进行X线检查。注意到循环测试结果存在很大差异。用SRS骨水泥增强后的标本平均每个周期变形0.00195毫米，而对照组为每个周期1.013毫米（p<0.005）。当根据骨质量的好坏对结果进行分层时，也发现了类似程度的差异。肉眼检查和X线片显示可重复性地产生了IIB型关节内移位骨折，计算机断层扫描显示所有标本几乎都实现了解剖重建。计算机断层扫描显示骨缺损填充良好，循环加载后没有骨水泥失效的迹象
