Shea J E, Vajda E G, Bloebaum R D
Bone and Joint Research Laboratory, VA Medical Center, Salt Lake City, UT 84148, USA.
J Anat. 2001 Feb;198(Pt 2):153-62. doi: 10.1046/j.1469-7580.2001.19820153.x.
Femoral neck fractures are a major cause of morbidity and mortality in elderly humans. In addition to the age-related loss of cancellous bone, changes to the microstructure and morphology of the metaphyseal cortex may be a contributing factor in osteoporotic hip fractures. Recent investigations have identified a hypermineralised tissue on the neck of the femur and trochanteric region that increases in fractional area with advancing age in both males (Boyce & Bloebaum, 1993) and females (Vajda & Bloebaum, 1999). The aim of this study was to determine if the hypermineralised tissue previously observed on the proximal femur is calcified fibrocartilage. Regional variations in the fractional area of hypermineralised tissue, cortical bone, and porosity of the cortical bone along the neck of the femur and lesser trochanter were also quantified. Comparison of back scattered electron and light microscope images of the same area show that regions of hypermineralised tissue correlate with the regions of calcified fibrocartilage from tendon and capsular insertions. The hypermineralised tissue and calcified fibrocartilage had similar morphological features such as the interdigitations of the calcified fibrocartilage into the bone, lacunar spaces, and distinctly shaped pores adjacent to the 2 tissues. Regions of the neck that did not contain insertions were covered with periosteum. There were no regional differences (P > 0.05) on the superior and inferior femoral neck in terms of the percentage area of hypermineralised calcified fibrocartilage, cortical bone, or cortical bone porosity. The lesser trochanter exhibited regional differences in the fractional area of hypermineralised calcified fibrocartilage (P = 0.007) and cortical bone (P = 0.007) but not porosity of the cortical bone (P > 0.05). The effects of calcified fibrocartilage on femoral neck periosteal expansion, repair, and mechanics are unknown, but may play a role in osteoporotic fractures and intracapsular fracture healing.
股骨颈骨折是老年人发病和死亡的主要原因。除了与年龄相关的松质骨流失外，干骺端皮质骨的微观结构和形态变化可能是骨质疏松性髋部骨折的一个促成因素。最近的研究已经在股骨颈和转子区发现了一种矿化过度的组织，随着年龄的增长，男性（博伊斯和布洛鲍姆，1993年）和女性（瓦伊达和布洛鲍姆，1999年）的该组织所占面积比例都会增加。本研究的目的是确定先前在股骨近端观察到的矿化过度组织是否为钙化纤维软骨。还对沿股骨颈和小转子的矿化过度组织、皮质骨的面积分数以及皮质骨孔隙率的区域差异进行了量化。同一区域的背散射电子图像和光学显微镜图像的比较表明，矿化过度组织的区域与来自肌腱和关节囊附着处的钙化纤维软骨区域相关。矿化过度组织和钙化纤维软骨具有相似的形态特征，如钙化纤维软骨向骨内的交错、腔隙以及与这两种组织相邻的形状独特的孔隙。不含附着处的颈部区域覆盖有骨膜。在股骨颈上下部，矿化钙化纤维软骨、皮质骨或皮质骨孔隙率的面积百分比方面没有区域差异（P>0.05）。小转子在矿化钙化纤维软骨（P = 0.007）和皮质骨（P = 0.007）的面积分数上表现出区域差异，但在皮质骨孔隙率方面没有差异（P>0.05）。钙化纤维软骨对股骨颈骨膜扩张、修复和力学的影响尚不清楚，但可能在骨质疏松性骨折和囊内骨折愈合中起作用。
