Center for Musculoskeletal Surgery and Julius Wolff Institute, Charité Campus Virchow Klinikum-Forum 4, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
Clin Orthop Relat Res. 2011 Nov;469(11):3102-10. doi: 10.1007/s11999-011-1914-y.
Gender and stability of fixation independently influence bone regeneration but their combined effects are unclear.
QUESTIONS/PURPOSES: In a pilot study we determined the combined influence of gender and fixation stability on the callus of middle-aged rats regarding (1) biomechanical properties; (2) bridging over time; (3) callus formation; and (4) callus size, geometry, mineralization, and microstructure.
We osteotomized the left femur of 32 Sprague-Dawley rats (12 months old). Femurs were externally fixed with a gap of 1.5 mm in four groups of eight animals each: female semirigid, male semirigid, female rigid, and male rigid. Qualitative and quantitative in vivo radiographic analyses were performed twice weekly. Six weeks postoperatively, harvested femora were evaluated using micro-CT and biomechanical testing.
Torsional stiffness and maximum torque at failure were higher in male and in semirigidly fixed fractures. Radiographic analysis revealed earlier bridging and callus formation in both male groups. Micro-CT analysis showed a larger callus size, altered geometry, and microstructure in males and semirigidly fixed animals, whereas mineralization was similar in all animals.
Our data suggest female gender represents an independent risk factor for bone healing in middle-aged rats. Although healing in females was delayed compared with males, they exhibited a similar response (superior callus properties) to a more semirigid fixation.
While female gender appears to reflect a risk for impaired bone healing in middle-aged female rats, clinical studies would be required to confirm the finding in humans.
性别和固定的稳定性独立影响骨再生，但它们的综合影响尚不清楚。
问题/目的：在一项初步研究中，我们确定了性别和固定稳定性对中年大鼠骨痂的综合影响，涉及：(1)生物力学特性；(2)随时间的桥接；(3)骨痂形成；以及(4)骨痂大小、几何形状、矿化和微结构。
我们对 32 只 Sprague-Dawley 大鼠（12 个月大）的左侧股骨进行了截骨。股骨在四个组中分别用 1.5mm 的间隙进行外部固定，每组有 8 只动物：雌性半刚性、雄性半刚性、雌性刚性和雄性刚性。每周进行两次定性和定量的体内放射学分析。术后 6 周，对采集的股骨进行 micro-CT 和生物力学测试。
扭转刚度和破坏时的最大扭矩在雄性和半刚性固定骨折中较高。放射学分析显示，在两性组中均较早出现桥接和骨痂形成。micro-CT 分析显示，雄性和半刚性固定动物的骨痂大小更大、几何形状和微结构发生改变，而所有动物的矿化相似。
我们的数据表明，女性性别是中年大鼠骨愈合的一个独立危险因素。尽管女性的愈合较男性延迟，但她们对更半刚性固定的反应（更好的骨痂特性）相似。
虽然女性性别似乎反映了中年女性大鼠骨愈合受损的风险，但需要进行临床研究来证实这一发现。
